Class 11 Medical Biology - Transport In Plants

Differentiate between absorption and adsorption.

Absorption is a process in which anion or molecule gets into a cell or body through a membrane. Whereas adsorption is a process in which the accumulation of molecules occurs at the contact surface. It never gets into a cell or body through membrane.
Absorption is not surface phenomenon and intermolecular forces do not occur, whereas in adsorption the molecules in contact are held by intermolecular forces.
Absorption helps in the uptake of minerals and water in plants, whereas adsorption helps in the imbibition of water and enzyme activity. Absorption is sometimes an endothermic process whereas adsorption is an exothermic process.

Loss of water as droplets from the margins of certain leaves is called ?

Loss of water as droplets from the margins of certain leaves is called guttation.

Differentiate between Guttation and bleeding.

Guttation	Bleeding
The water appears as tiny drops along the margins or the tips of the leaves, especially in the early mornings. This loss of excessive water is called guttation.	Loss of water through a cut stem or wound is called bleeding

Differentiate between guttation and bleeding in plants.

Guttation

Bleeding

The leaves of certain plants exhibit droplets of water along their margins in the morning. This particular happens in plants growing in warm humid conditions.

Water escapes from specialized structures called hydathodes.

This happens only due to injury. The plant sap escapes from the ruptured or cuts surfaces of a plant. The root pressure generated by a plant assists in bleeding.

Osmosis is a special kind of diffusion, in which water diffuses across the cell membrane. The rate and direction of osmosis depends upon both _____.

Osmosis is a special kind of diffusion, in which water diffuses across the cell membrane. The rate and direction of osmosis depends upon both pressure gradient and concentration gradient

The $$C_4$$ plants are twice as efficient as $$C_3$$ plants in terms of fixing $$CO_2$$ but lose only as much water as $$C_3$$ plants for the same amount of $$CO_2$$ fixed.

The $$C_4$$ plants are twice as efficient as $$C_3$$ plants in terms of fixing $$CO_2$$ but lose only half as much water as $$C_3$$ plants for the same amount of $$CO_2$$ fixed.

Diffusion is a slow process and is not dependent on a system. Why?

Diffusion across two surfaces depends upon the permeability of the interface. This interface can be any thing and living structure or non living structure and cell membrane is an interface between the extra cellular and intracellular space however the diffusion does not depend on living system because it depends only on gradient and diffusion can occur in body living and non living systems unlike active transport which only occurs in living systems.

What are apoplast and symplast?

There are two types of transport pathway for the conduction of the water from one region to the other. The path followed by the water can be symplast or apoplast pathway. The symplast is the pathway in which the water molecules moves through the plasmodesmata region in the cells. The symplast is the living region present between two cells which connects one cell with the other. The apoplast pathway is the path in which the water is moving between the intercellular spaces. The apoplast includes the non living spaces between the cells and the cell membranes.

Osmosis is an example of active transport. True or False? Explain.

Active transport involves:

1. Use of energy

2. Movement against concentration gradient

3. Special membrane components.

Osmosis involves :

1. No use of energy

2. Movement along the concentration gradient

3. Any semi permeable membrane

These two are not the same things and osmosis is not an example of active transport.

So, the correct answer is 'False'.

"Transpiration is necessary evil". Explain.

Transpiration is the process in which there is a loss of water in the form of water vapour from the stomatal openings. It is beneficial to the plants due to its role in the ascent of sap, absorption, and translocation of mineral salts and in the regulation of the temperature of plant tissues.
However, transpiration also causes loss of water unnecessarily. Due to the process of transpiration, there is pressure on the plant for the absorption of water. Therefore, the process of transpiration is called a necessary evil.

Which process takes place in the water purifier?

This process is the exact reversal of osmosis. This is a very common method in households and other places for purification of water.

This process is known as 'Reverse osmosis'.

Give reasons for this sentence:
A plant cell when kept in a hypertonic salt solution for about $$30$$ minutes turns flaccid.

When a living cell, such as the cell of a leaf of an aquatic plant, is placed in freshwater, it remains in a fully distended condition. Its plasma membrane remains in close contact with the cell wall and presses against it just like a rubber bladder of a football pushing against the leather casing. If this plant cell is now kept in a hypertonic solution for 30 minutes, it will lose its distended appearance, the cytoplasm will shrink and the plasma membrane will withdraw from the cell wall, this is called plasmolysis and the cells in this state are said to be limp or flaccid.

Differentiate between.
Facilitated diffusion and active transport

The facilitated diffusion takes place along the concentration gradient and does not require energy. On the other hand, in active transport molecules move against the concentration gradient and this process requires energy

Explain the symplastic movement and apoplastic movement of water in the cell.

Water passes into the root hair from the soil along a water potential gradient. In the symplastic movement, the water moves along the same water potential gradient, but across the inter-connected cytoplasm (symplast) of the cells of the root system. On the other hand, in apoplastic movement, the movement of water is through adjacent cell walls (apoplast) from the root hair cell to the xylem.

Why do molecules diffuse down their concentration gradients?

A concentration gradient is the difference in concentration of a substance from one location to another. A molecule diffuses down its concentration gradient by moving from one region of higher concentration to a region of lower concentration

The water potential of pure water changes when solute is added to it

The water potential is the potential energy per unit volume in the solution which is 100% for pure water, when solute is added to pure water, the potential decreases as the solute particles lead to interfere with the potential of pure water.

Define chemiosmosis.

Chemiosmosis is the movement of ions across a semipermeable membrane, down their electrochemical gradient. ATP synthase is the enzyme that makes ATP by chemiosmosis. It allows protons to pass through the membrane and uses the free energy difference to phosphorylate adenosine diphosphate (ADP), making ATP. The generation of ATP by chemiosmosis occurs in mitochondria and chloroplasts, as well as in most bacteria and archaea, an electron transport chain pumps H+ ions in the thylakoid spaces through thylakoid membranes. The energy from the electron movement through electron transport chains cross through ATP synthase which allows the proton to pass through them and use this free energy difference to photophosphorylate ADP making ATP.

Define guttation.

Guttation is the loss of water in the form of water droplets from hydathodes (small pores) on the leaf margin of a small herbaceous plant. Guttation is not to be confused with dew, which condenses from the atmosphere onto the plant surface.

What is imbibition?

Imbibition is process of diffusion where the water is absorbed by the colloids of the solid substance and increase in their volume. For example when the dry wood or stem of a tree is soaked in water the colloids present in the wood absorb the water and the volume of the wood increases which was used by the ancient man for splitting stones and rocks.
Also the germination of the seeds that takes place is due to imbibition where the water is absorbed by the seed and it helps them emerge out of the soil to germinate into a plant.

Briefly explain the following:
i) Osmosis
ii) Allele
iii) Pulse
iv) Reflex action
v) Synapse

Osmosis is the movement of the solvent through a semipermeable membrane down the concentration gradient.

The alternate forms of a gene are called as alleles.

Pulse refers to the vibration felt in arterial walls due to the expansion of the aorta after ventricular contraction.

An automatic, quick and innate response to particular stimuli that is mediated by the reflex arc is known as a reflex action.

Two neurons are never physically connected to each other and synapse is the gap between two neurons are in close proximity to allow the flow of information from one neuron is transmitted to the next one.

Which of the following has highest water potential ?
(i) 1 M Salt solution
(ii) 1 M Sugar solution
(iii) Distilled water
(iv) 1 M Sugar solution with 2-3 bars pressure

Distilled water always has the highest water potential since it has no solute dissolved in it as well as the pressure on the system is zero.

As we go on adding a solute to water, it's water potential decreases. Solute potential has a negative value and increases in solute will lower down the water potential of the solution.

Hence the highest water potential will be of pure water.

The figure given below represents experimental set up with a weighing machine to demonstrate a particular process in plants. The experimental set up was placed in bright sunlight. Study the diagram and answer the following questions:
What is the purpose of keeping the test tube B in the experimental set up?

'B' acts as a control to prove that water is lost in the form of water vapour due to transpiration from the aerial parts/ leaves of the plant.

In an experimental set-up, a dye was placed at the bottom of a beaker filled with water as shown in figure A, below. After some time, the entire water in the beaker got coloured uniformly, as shown in figure D.
(a) Name and define the phenomenon shown in the experiment.

The phenomenon is diffusion. Diffusion is the movement of the molecules or atoms of a substance from the region of higher concentration to the region of lower concentration.

Differentiate between
Water potential and diffusion pressure deficit.

Water potential is the difference between the free energy of water molecules in pure water and solution, whereas diffusion pressure deficit (DPD) is the difference in diffusion pressure between a solution and pure solvent. Moreover, water potential has negative value, whereas diffusion pressure deficit has positive value.

Fill in the blanks :
The water potential of pure water is ...............

Water potential of pure water is zero.

This is because there is no solute present in it and the pressure on the system is also zero.

Hence the answer is zero

What would be $$\Psi _p$$ of a flaccid cell?

A flaccid cell is the one which has lost a lot of water. In this condition, the pressure potential becomes zero. This is because pressure potential is equal to water potential here and the water potential is zero for a flaccid cell.

So the answer is zero.

Describe Uniporter Catalyzed Transport ?

Uniport type membrane transport proteins operate to important many types of molecules into the cell driven only by a concentration gradient, a process termed as facilitated transport or facilitated diffusion.
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When separated by a semipermeable membrane, water enters the sugar solution. What would you call the sugar solution as osmotically active or inactive?

Here sugar solution is osmotically active because the solutes that cause osmosis are known as osmotically active particles. As water is entering through osmosis, the above condition becomes true and we can consider the sugar solution as osmotically active.

Explain an activity to show that stem conducts water and other substances.

Activity to show that stem conducts water and other substances:

1) Take some water in a glass.

2) Add few drops of red ink to the water.

3) Cut the stem of a herb plant from its base.

4) Put it in the glass.

5) It can be observed that some parts of the stem become red indicating that water is being conducted through the stem.

Distinguish uniport transport method from passive diffusion ?

Three main features distinguish uniport transport from passive diffusion:--

1. The rate of transport is far higher than predicted by Fick's equation.

2.Transport is specific

3.Transport occurs via a limited number of transporter proteins rather than throughout the phospholipid bilayer.

What will happen if a plant cell is kept in solution of higher water potential?

A solution of higher water potential means that the solution is hypotonic to the plant cell. In this condition, the cell starts absorbing water and becomes swollen or turgid. This process goes on until the difference between theit water potentials become zero. If this state is not achieved then the cell may even burst due to excessive amount of absorption.

A plant is transpiring rapidly. Will it show root pressure also?

Root pressure is developed due to the concentration of solute in the root xylem which causes the water from the soil to enter the root cells. If transpiration is occurring rapidly then the ions will be taken up the stem and the root pressure won't be developed or we can say a negative root pressure is developed.

What would be $$\Psi _p$$ of a plasmolysed cell ?

Since the Turgor pressure of plasmolysis cell decreases due to removal of water out of the cell, the pressure potential also decreases.

Hence the pressure potential for plasmolysed cell is negative.

Compare the imbibing capacities of pea and wheat seeds.

The pea plant is a legume. The pea seeds are mostly composed of protein. The imbibing capacity of the protein is very high. Thus, there will be more imbibition of water by the pea seeds. The process of germination occurs in less time. The wheat seeds are cereals and are a rich source of carbohydrate and starch. The imbibing capacity of the carbohydrates is very low. Thus, the seeds of wheat will show less imbibition of water. This will delay the process of germination in less water.

How does carbon dioxide diffuse in submerged plants?

The oxygen is in the dissolved state in the water of the aquatic reserves. In the submerged plants, there are structures through which the water is taken in. The water can freely move in the spaces of the aerenchymal cells in the aquatic plants. The water is circulated in the aerenchyma cells and the oxygen which is dissolved in the water is used for respiration. The carbon dioxide which is required for photosynthesis, obtained by the same process of circulation of water.

i) Solution of 'A' chamber has higher $$Psi$$ W.
ii) Solution of 'B' chamber has higher $$Psi \, s$$
iii) At equilibrium 'A' chamber will have lower $$Psi \,w$$
iv) Osmosis occurs in A $$\rightarrow$$ B direction.
How many above conclusions are incorrect with respect to given set up ?

At equilibrium 'A' chamber will have lower Psiw and Solution of 'B' chamber has higher Psis are incorrect with respect to given set up.

What is root pressure? How is it useful to plants?

The root pressure is the pressure which is exerted on the liquid contents of the fully turgid cortex cells of the root, forcing some of it into the xylem vessels and up through the stem. It is a vital phenomenon and depends upon the activity of the living cells of the root. This is the osmotic pressure which causes the water in the xylem to travel in the upward direction. This is necessary for supplying the cells of the plants with water and the mineral nutrients. This pressure is responsible for the absorption of water and the essential minerals from the soil.

State four differences between transpiration and guttation.

Transpiration	Guttation
1) Water escapes in the form of vapours.	Water escapes in liquid form.
2) Mainly occurs through the stomata.	Occurs through the hydathodes.
3) Only pure water escapes out.	Water moving out contains minerals dissolved in it.
4) Mostly occurs during the day.	Occurs at night or early morning.

Write about respiration in mangroves that grow in marshylands.

The mangroves are the plants which grow in marshy areas. The plant roots cannot survive and respire in these marshy land due to less concentration of oxygen. The plants have a special type of roots called as pneumatophores. These are finger-like projections of roots which arise in an upward direction and possess lenticels. The air is taken through the pores of lenticels and respiration is carried out by the plant cells.

Doors of house swell up in the rainy season due to what reasons?

Doors of house swell up in the rainy season due to imbibition. It is a physical process of adsorption of water on the surface of adsorbent material. During rainy season the concentration of water vapor is more in air and if the doors are not properly protected by paints or varnishes the wood in them will imbibe water from water vapors present in air and swell.

Transpiration is a necessary evil. Justify.

Transpiration is the process in which there is a loss of water in the form of water vapour from the stomatal openings. It is beneficial to the plants due to its role in the ascent of sap, absorption and translocation of mineral salts and in the regulation of the temperature of plant tissues. However, transpiration also causes loss of water unnecessarily. Due to the process of transpiration, there is pressure on the plant for the absorption of water. Therefore, the process of transpiration is called a necessary evil.

The phenomenon by which living or dead plant cells absorb water by surface attraction.

Imbibition is the absorption of water by living or dead plant cells by surface attraction e.g., absorption of water by seeds.

The bending movements of certain flowers towards the sun and the sleep movements of certain plants at night are examples of ..................

The bending movements of certain flowers towards the sun and the sleep movements of certain plants at night are examples of nastic movements.

What is root pressure?

Root pressure is the positive hydrostatic pressure that develops in the xylem sap of the roots.
Therefore, when water enters into the xylem from pericycle, a pressure is developed in the xylem of the roots which raise the water to a certain height in the xylem.
This pressure is called root pressure.

What is the water potential value of pure water? If $$5$$ grams of sodium chloride is added, what will happen to its water potential value?

The water potential of the pure water is equal to zero. When there is an addition of solute, the water potential is decreased. So, when there is an addition of 5 gram of the sodium chloride, the value of the water potential will be decreased. The value will become more negative.

Define and explain water potential

The difference of free energy present in the water of a system when compared with the free energy of pure water at constant temperature and pressure is called water potential. The concept of water potential was first given by Slatyer and Taylor. It is based on the on two important principles free energy and chemical potential. Water potential works on the laws of thermodynamics.

The symbol of water potential is ᴪ(psi). It is a relative measure and water potential of pure water is arbitrarily set at zero. So, the water potential of a solution is always expressed in negative values. It is always measured in Megapascals.

In plants, water potential is influenced by three components, osmotic potential, pressure potential, and matric potential.

Osmotic potential: The amount of water get lowered in a solution by the addition of solutes is called Osmotic potential.

The symbol of osmotic potential is (ᴪ_π-). It is always showing a negative value.

Pressure potential: The amount of water potential increases after the addition of water in a cell is called Pressure potential. The symbol of pressure potential is (ᴪ_p). It always shows a positive value.

Matric potential: The amount or quantum of decrease of water potential in a solution on account of matric forces is called Matric potential.

It is represented by a symbol tau.

it always has negative value.

The relation between water potential, osmotic potential and pressure potential is ᴪw= ᴪ_π+ᴪ_p +ᴪ_t

but in living cells matric potential is negligible.

So, water potential is calculated as the sum of the osmotic potential and pressure potential. ᴪ_w = ᴪ_π+ᴪ_p

Importance of water potential:

It regulates the direction of movement of water in plants.

In plants, water always move from high water potential region to low water potential region.

Why do dry seeds imbibe water when placed in it?

Germination begins when a seed is supplied with water for non-dormant plants as soon as the temperature is suitable. Imbibition is a form of diffusion that causes water to move along a gradient of diffusion. Because of this method some dried and semi-dried matter absorbs water.Dry plant absorption of water is called imbibition. As seeds absorb water, they grow and hydrate enzymes and food supplies. Hydrated enzymes become active and the seed increases its metabolic activity to generate energy for the process of development. Furthermore, the water leads stress in the cells to rise and they can enlarge. As the seed absorbs water, the seed coat also losens due to which it can germinate easily as the radicle and plumule begin to grow.

Describe an activity to show the effect of low pressure and particulate nuclei over water vapours?

Pour 5-10 mL of water into an empty mineral water bottle. Close the bottle rigidly. Shake the bottle well or keep it in sun for about 10 minutes. This causes evaporation of a major part of water so that the bottle becomes saturated with water vapors. Take lighted incense stick. Open the cap of the bottle and introduce some smoke of incense stick into it. Quickly replace the cap tightly.' Press the bottle between your hands and then release the pressure. Repeat the process 2-3times. Entry of smoke from incense stick makes the air foggy inside the bottle. The smoke particles function as nuclei and cause condensation of water vapors over them just as what happens during cloud formation. These water droplets appear on the sides of the bottle which come to have low pressure when pressure is released from the bottle. It is just like raining in response to low pressure.

Briefly describe water potential. What are the factors affecting it?

Water potential quantifies the tendency of water to move from one part to the other during various cellular processes such as diffusion, osmosis, etc. It is denoted by the Greek letter Psi or Ψ and is expressed in Pascals (Pa). The water potential of pure water is always taken as zero at standard temperature and pressure.

Water potential (Ψw) is expressed as the sum of solute potential (Ψs) and pressure potential (Ψp).

Ψw = Ψs + Ψp

When some solute is dissolved in water, the water potential of pure water decreases. This is termed as solute potential (Ψs), which is always negative. For a solution at atmospheric pressure, Ψw = Ψs.

The water potential of pure water or a solution increases on the application of pressure values more than atmospheric pressure. It is termed as pressure potential. It is denoted by Ψp and has a positive value, although a negative pressure potential is present in the xylem. This pressure potential plays a major role in the ascent of water through the stem.

Explain what will happen to a plant cell, if it is kept in a solution having higher water potential.

Water potential is the hydrostatic pressure exerted by water due to its kinetic energy. The hypotonic solution has a greater concentration of water so they have high water potential.
When a plant cell is placed in a hypotonic solution or a solution having higher water potential, the water diffuses into the cell (i.e., the movement is observed from higher to lower water pressure region). The entry of water into the plant cell exerts pressure on the rigid cell wall. This is called turgor pressure.

What is osmosis?

$$\textbf{Explanation}$$

Osmosis is the spontaneous net movement of solvent molecules through a selectively permeable membrane into a region of higher solute concentration from a lower concentration, in the direction that tends to equalize the solute concentrations on the two sides.

Given below is an experimental set up to demonstrate a particular process. Study the same and answer the following questions.
i. Name the physiological process being studied.
ii. Explain the process mentioned above.
iii. What is the aim of the above experiment?
iv. What would you observe in the experimental set up after an hour? Give a reason to support your answer.
v. Mention any three adaptations found in plants to overcome the physiological process mentioned in (i) above.

(i) Transpiration
(ii) Two cobalt chloride papers are attached, one on the dorsal and the other on the ventral surface of a dorsiventral leaf with the help of glass slide and clips. The set up is left in the open for few hours.
(iii) To show that more transpiration occurs from the ventral surface of a dicot leaf.
(iv) After an hour, the cobalt chloride paper placed on the ventral surface turns blue to pink faster than the one on the upper surface as the number of stomata are more on the ventral surface, so more transpiration takes place from the lower surface.
(v) 1. Cuticle becomes thick
2. Leaves become narrow
3. Stomata covered by hair-like structures

Define:
(i) Radial vascular bundle (ii) Rigor mortis (iii) Root pressure

(i) In radial vascular bundles, xylem and phloem occur alternately on different radii e.g., in roots.

(ii) Rigor mortis is the medical term that is used to describe the hardening of body muscles after death. It's the result of the body's loss of adenosine triphosphate (ATP), which is a substance that gives energy to the muscles.
(iii) The pressure exerted on the liquid contents of the fully turgid cortex cells of the root, forcing some of it into the xylem vessels and up through the stem. It is a vital phenomenon and depends upon the activity of the living cells of root.

Explain the process of guttation with diagram.

Oozing out of water from the margins of the leaves in the form of water droplets is called guttation. It takes place during the night and the secreted water has minerals dissolved in it. For example, guttation is shown by the leaves of tomato, some grasses, and oat. There are hydathodes on the margins of the leaves of these plants which have ends of veins (tracheids).
The hydathodes are made of inactive guard cells having a cavity underneath. The cavity is surrounded from all sides by special parenchymatous cells called Epithem. These cells take water from the xylem to release it outside in the form of drops of water.

The movement of water molecule from a region of higher concentration to a region of its lower concentration through a semi permeable membrane is called Osmosis.
a) In the above statement, how will you differentiate active transport from passive transport ?

Active transport involves:

1. Use of energy

2. Movement against concentration gradient

3. Special membrane components.

Passive transport :

1. No use of energy

2. Movement along the concentration gradient

3. Any semi permeable membrane

Hence osmosis is a passive transport.

Soil provides water and .............. to plants.

Soil is the main source of water and nutrients to the plants. Nutrients include mineral elements like nitrogen, phosphorus, etc.

The loss of water in the form of droplets from the margins of leaves is called as what?

The loss of water in the form of droplets from the margins of leaves is called as guttation. There are hydathodes i.e., gland responsible for the loss of water in guttation.

What is transpiration?

Explanation:

Transpiration is the loss of water in the form of vapour, from stomata.
It takes place by generating a pulling force responsible for the ascent of sap, and minerals dissolved in water enter the plant body due to water replacing the subsequent gaps created due to evaporation.

Transpiration is essential for:
1. Creates transpiration pull for absorption and transport in plants.

2. Supplies water needed for photosynthesis.

3. Transports minerals along with water from the soil to various parts of the plant.

4. Causes cooling effect on leaf surfaces. Can lower the temperature up to 10-15 degrees.

Match the columns :

$$\textbf{Solution}$$

$$\bullet$$ $$\textbf{Option A}$$ Diffusion is the process in which there is spontaneous movement of the molecules from an area of higher concentration to an area of lower concentration. This process helps in the free movement of Ions and gases during the process of transpiration through stomata. Correct match is 4.

$$\bullet$$ $$\textbf{Option B}$$ Osmosis is the process in which the molecules are diffused from a region of higher concentration to origin of lower concentration through a semipermeable membrane. So the correct match is 3.

$$\bullet$$ $$\textbf{Option C}$$ Imbibition is a process in which the water is adsorbed by the solid particles without the formation of a solution. It occurs in hydrophytes substances which are water living substances. So, the correct match is 1.

$$\bullet$$ $$\textbf{Option D}$$ Plasmolysis is a process in which the protoplasm shrinks due to the loss of water when the cell is placed in a hypertonic solution. So, the correct match is 2.

Therefore, A-4, B-3, C-1, D-2.

Explain what will happen to a plant cell if it is kept in a solution having higher water potential?

Higher water potential can be seen in case of a hypotonic solution. If the cell is kept in a hypotonic solution then it starts absorbing water. The cell absorbs water and becomes swollen or turgid. This process goes on until the difference in their water potential becomes zero. If the water absorbed is too much for the cell to contain then it bursts.

What are the factors that affect the rate of diffusion ?

Many factors affect the rate of diffusion such as :

(I) Density of the substance

(ii) Density or permeability of the medium

(iii) Temperature

(iv) Diffusion pressure

(v) Distance

Density increase reduces diffusion.

Increase in temperature causes an increase in diffusion.

Increase in temperature increases diffusion as the kinetic energy of particles increases.

Why is energy required to develop root pressure?

Energy is required for the development of root pressure because the uptake of ions from the soil is an active transport process. Active intake of ions and minerals require energy. As they start accumulating in the root xylem, the water potential in the cells is decreased significantly. This causes the water from the soil to enter the root cells passively through osmosis. Hence a root pressure is developed by the expenditure of energy.

Define osmosis.

Explanation -

Osmosis is the movement of solvent molecules via a selectively permeable membrane . The movement is from a region of high water potential to a region of low water potential, so as to equalize the water potential on both sides .

What is water potential? Why is it negative in value?

Water potential is defined as the potential energy of water per unit volume relative to pure water under the same temperature and pressure conditions.

Water potential is negative in plants because of the high number of solutes present in it. Solute potential has a negative value and hence decreases the overall water potential making its value negative.

Name the pores through which guttation occurs.

The pores through which guttation occurs are known as 'Hydathodes'. Guttation is the process in which water droplets are released from the pores of the plants.

In an osmotic system, one chamber has a $$\Psi $$ of -1000 kPa while the other has -500 kPa. Which chamber has higher water potential ($$\Psi_w$$)?

The chamber having Pressure potential of -500 kPa has a higher water potential. A solution having a higher water potential is a dilute solution.

Define transpiration. Name the types of transpiration. Give the mechanism of transpiration giving V.S. of leaf.

Transpiration is the process of release of water vapour from the pores of the plants.

Types of transpiration:

1. Stomatal transpiration

2. Lenticular transpiration

3. Cuticular transpiration

4. Bark transpiration

Mechanism of transpiration :

The water needs appropriate conditions to get converted into vapour which is provided by the energy of sunlight as well as the heat of the plant organs. The atmosphere of has very low water potential. All these conditions favour formation of water vapours. The intercellular spaces of the transpiring organs are mostly filled with and saturated with water vapours. These vapours are released into the atmosphere. The neighbouring cells lose their water to produce vapours and in turn they take up water from the xylem tissues.

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Set up an experiment to demonstrate root pressure.

Aim : To demonstrate root pressure.

Material required : A potted plant, knife, rubber tube, glass tube, coloured water.

Procedure: Water the herbaceous plants and keep it for some time. Then cut off the upper part of the stem and attach a narrow glass tube on it. Fill the glass tube with coloured water. Mark the level of water and connect a manometer to the glass tube. Record your observations after some time.

Observations: The colour water rises in level and the manometer shows the root pressure by the increase in mercury level.

Conclusion: The water level increases as a result of root presure. The root pressure is of a small magnitude as shown by the manometer.

The diagram given below represents a plant cell after being placed in a strong sugar solution. Study the diagram and answer the questions that follow:
How can the above cell be brought back to its original condition? Mention the scientific term for the recovery of the cell.

The cell can be brought back to its original condition if it is placed in hypotonic solution or in pure water. It is called as deplasmolysis.

The diagrams given below represent the relationship between a mouse and a physiological process that occurs in green plants. Study the diagrams and answer the questions that follow:
Why did the mouse die in bell jar $$B$$?

In jar B, the mouse died because of lack of oxygen.

The diagram given below represents a plant cell after being placed in a strong sugar solution. Study the diagram and answer the questions that follow:
What is the state of the cell shown in the diagram?

The cell is in flaccid state. It is plasmolysed cell.

An experiment was set up as shown in the figure below. After some time, the water level in test tube A fell down but not in test tube B.
Why was there a fall in the water level of test tube A and not in that of test tube B?

In test tube A the water level falls because the plant root dipped in root will absorb it and in test tube B there is no change of water level because there is no root dipped in it.

What is guttation? Explain with the help of diagram of the vertical section of hydathode present on apical part of tomato or primula leaf.

Guttation is the loss of water in the liquid state from uninjured parts of plants, usually from tips and margins of leaves. In this, water exudes from the group of leaf cells called hydathodes.

A hydathode is an opening or pores in the leaf epidermis, around, which are grouped as several thin-walled parenchyma cells. It occurs during the night or early morning when there is high atmospheric humidity and transpiration is less. Guttation depends on the root pressure. The development of root pressure in a plant leads to positive hydrostatic pressure in xylem sap throughout the plant. Because of water-conducting xylem elements is a vascular bundle terminate in a hydathode, xylem sap is forced to flow through the hydathodes.

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Fill in the blank by choosing the correct alternative from those given in brackets.
When placed in a more concentrated solution, the cell contents will ............... (shrink/swell up)

When placed in a more concentrated solution, the cell contents will shrink.

Give appropriate biological or technical terms for the following.
Movement of molecules of a substance from their higher concentration to lower concentration when they are in direct contact.

Diffusion

In an experimental set-up, a dye was placed at the bottom of a beaker filled with water as shown in figure A, below. After some time, the entire water in the beaker got coloured uniformly, as shown in figure D.
(b) In all the four figures, two kinds of molecules are shown symbolically larger and smaller. Which molecules are of the solute and which are of the solvent?
Larger ..................................................................
Smaller ..................................................................

(a) The larger molecules are of the solute (dye)

(b) The smaller molecules are of the solvent (water)

Differentiate between Turgidity and Flaccidity.

Turgidity	Flaccidity
When a cell reaches a state where it cannot accommodate any more water, i.e., it is fully distended, it is called turgid and the condition is called turgidity.	It is the condition in which the cell content is shrunken and away from the cell wall due to loss of water

The process by which the intact plant loses water in the form of droplets is called

The process where an intact plant loses water in the form of droplets is called Guttation.

How you can demonstrate the phenomenon of osmosis in the laboratory?

1. Remove the outer skin of the potato and cut the one end flat.

2. Scoop out a cavity from the other end of the potato running almost upto the bottom.

3. Fill one tuber with concentrated solution of sugar and water in the other.

4. Mark the level of the sugar solution and water with the help of pins.

5. Place the potato containing sugar solution in a beaker containing water, and the potato containing water in the beaker containing sugar solution.

The level of the sugar solution in the first potato increases because the water moves from the beaker into the cavity through the semipermeable membrane of potato.

The level of the water in the potato containing water decreases because the water moves from the cavity into the beaker through the semipermeable membrane.

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Differentiate between osmosis and imbibition.

The phenomenon of osmosis was discovered by Nollet in 1748. It is a kind of diffusion that plays a role in the movement of water into and within plants.
It is defined as the diffusion of water molecules through a differentially permeable membrane or semi-permeable membrane.
Imbibition is basically a diffusion process. It may be regarded as a difference in the diffusion pressure between the liquid in the external medium and the liquid is the imbibant (substance).

Demonstrate the phenomenon of transpiration.

Transpiration is the evaporation of water from the surface of leaves through stomata. The phenomenon of transpiration can be explained by Bell jar experiment.

REQUIREMENTS:

Bell jar
Well watered potted plant
Rubber sheet
Glass plate

PROCEDURE:

Take the well watered potted plant and cover it with the rubber sheet. The aerial parts of the plant should be left uncovered.
Put the plant on the glass plate and cover with the bell jar.
Prepare a same setup but without a plant in the second bell jar.
Place the apparatus in sunlight for sometime.

OBSERVATIONS:

Water drops appear inside the walls of the bell jar containing potted plant whereas no water drops appear in the bell jar without a plant. This demonstrates that water is evaporated from the surface of leaves in presence of sunlight.
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Define the term plasmolysis.

Plasmolysis is the process in which cells lose water in a hypertonic solution. If a plant cell is placed in a hypertonic solution the plant cell loses water So the turgor pressure decreases to the point where the protoplasm of the cell peels away from the cell wall and leaves the gaps between the cell wall and the membrane which makes the plant cell shrink. A continued decrease in pressure eventually leads to cytorrhysis which is the complete collapse of the cell wall.

What is Guttation?

Guttation is the process of secretion of water droplets from the pores of plants. Effects of root pressure is observed at night and early morning when evaporation is low, excess water collects in the form of droplets around special openings of veins near the tip of grass blades, and leaves of many herbaceous plants. Such water loss in its liquid phase is known as guttation

What will be the direction of the movement of water when two solutions with $$\Psi_w = 0.2 MPa$$ and $$\Psi_w = 0.1 MPa$$ are separated by a selectively permeable membrane?

Chemical potential is a quantitative expression of the free energy associated with a substance. So water potential or the chemical potential of the water represents the free energy associated with water. It is denoted as Ψw.
Without any energy investment, water flows from regions of higher chemical potential to ones of lower chemical potential. So, in this case, net water movement occurs in the direction from solution with $$\psi_w$$=0.2M Pa to the solution with $$\psi_w$$=0.1M Pa (higher to lower).

Why we should take germinating seeds in a conical flask for the experiment carbon dioxide is given out during the process of respiration?

In conical flask experiment germinating seed is taken as it releases a large amount of carbon dioxide which is measurable. Moreover, as the seed come out of dormancy period and require more energy is becoming metabolically active so the amount of certain hormones is high like gibberings that helps them to increase the process of respiration and break down of starch occurs at higher rate this helps to increase the release of $$CO_2$$ from the seed.

How to compare the water potential and solute potential of two solutions?

Water potential and solute potential of two solutions can be compared by keeping the two solutions separated by a semi-permeable membrane like egg membrane at a constant pressure. The net direction and rate of flow of water between the solutions can be used to compare the water potential and solute potential. Water always moves from the system containing water at a higher water potential to the one at a lower water potential. In case of solute potential, water moves from a system with the lower solute potential to the one with higher solute potential.
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Give biological reasons for the following:
A closed can of dried seeds bursts open if some water enters it by accidents.

If we keep some dried seeds in a closed container and when some water enters the can, the container bursts and opens after some time.

This is because water is absorbed by the seeds by the process called imbibition and the seeds swell up. When the imbibing substance is kept in a confined space, the pressure is developed due to the increase in the volume of the imbibing. This is called imbibition pressure.

Because of the imbibition pressure developed in the container, it bursts and opens up.

Give reasons for the following:
Plasmolysis occurs in plant cells only and not in animal cells.

Plasmolysis is the process in which cells lose water (by the process of osmosis) in a hypertonic solution, the cell shrinks away from the cell wall (leaving a gap between them).

Plasmolysis occurs only in plant ells and not in animal cells because animals cells don't have cell walls in them.

And also because only plant cells have a cell membrane which is surrounded by a semi-rigid (to rigid in some cases) cell wall.

You took a fresh tomato and put it in a highly concentrated salt solution for 2 hr. Your little brother looked at it and stated, "The fat tomato is so thin now " What a magic?
(a) Define the phenomenon which has taken place.
(b) How does a cell wall help a plant to withstand hypotonic external media without bursting?

a) The phenomena which took place is known as exosmosis. Exosmosis is the movement of water outside the cell leaving the cell flaccid. When the tomato is placed in highly concentrated salt solution it shrinks. The salt concentration acts as a hypertonic solution due to which the water in the cells of tomato comes out in the concentrated salt solution by the process of exosmosis leaving the tomato flaccid.

b) A cell wall help a plant to withstand hypotonic external media without bursting as the cell takes the water by osmosis it swells and builds a turgor pressure the wall exerts an equal pressure against the swollen cell which is known as wall pressure. The turgor pressure is neutralized by wall pressure.

What do you mean by guttation ? Explain with example.

Guttation is an exudation of drops of xylem sap on the tips or edges of leaves of some vascular plants, such as grasses. It happens certain plants that have vascular systems, such grass, wheat, barely, tomatoes, strawberries and other small plants.

What would be $$\Psi_p$$ of a flaccid cell? Which organisms other than plants possess cell wall?

ᴪ$$_{p}$$ signifies the pressure potential of a cell. The pressure potential is the positive pressure developed in a system due to the entry of water into the system by osmosis.
The pressure potential is positive in the case of a turgid cell and negative is the case of a plasmolyzed cell. In a flaccid cell, there is no entry or exit of water due to osmosis so the pressure potential or ᴪ$$_{p}$$ of a flaccid cell would be zero (0).
The organisms other than plants which possess cell wall are fungi and few prokaryotes (bacterial type cells). The cell walls in each group of organisms vary distinctly.
The cell wall of plants is made of cellulose but the cell wall of fungi is made up of chitin and silica whereas in prokaryotes (bacterial type cells) the cell walls are composed of peptidoglycan.

What is the role of diffusion in plant and animals

Diffusion is a passive process involving the movement of molecules from a region of a higher concentration to one of a lower concentration (the term passive means that the process does not require an input of energy to take place). Diffusion can occur across partially permeable membranes, such as those of surrounding cells. In both plants and animals, diffusion is involved in the movement of important molecules into and out of cells. It is important for the uptake of substances needed by cells, and also the removal of waste products produced by the cells.

Mineral uptake in plants - Useful minerals and ions need to be taken up from soil into plants via root hair cells. These cells are adapted (through a large surface area and a large number) to maximize the rate of diffusion. Therefore, the useful molecules in the soil move down a concentration gradient and into the roots to be taken up by the plant. Many molecules found in the soil are essential for the growth and survival of plants, making diffusion a very important process.

Which process plays an important role in gaseous exchange between cell?

Diffusion is an important process through which exchange of gases takes place in a cell. This process is mainly directed by the difference in pressure of concentration. Hence the gases move from a highly concentrated region to a region of low concentration. Diffusion in plant cells mainly takes place during the process of photosynthesis where carbon dioxide diffuses into plant cells via the stomata on the leaf.

If thickness of diffusion membrane is increased then what will happen?

If the thickness of the diffusion membrane is increased then diffusion capacity across the membrane of a substance will be decreased and less exchange of gases against the membrane will take place.

Describe the phloem transport from source to sink

Organic solutes are translocated through the sieve tubes from the supplying end or source to the consumption end or sink. Sucrose transport involves the following three processes :

(A) Phloem loading is an active transport mechanism. It is carried out by a specific carrier protein molecules in the cell surface membrane of companion cells that uses ATP from the mesophyll cells to the sieve tubes in the veins of a leaf. Sugar moves from the photosynthesizing cells into a chain of mesophyll cells, transfer cells, to the phloem of a vascular bundle.

(B) Long distance transport of sucrose in the stem and root phloem.

(C) Phloem unloading is a passive transport mechanism from the sieve tubes to the cells at the root tip. It takes place passively down a concentration gradient of sucrose. The transfer cells are often present at unloading sites. Phloem unloading also requires metabolic energy, that is used by sink organs for respiration and biosynthetic reactions.

The wooden doors gets jammed in rainy season ...

The woods have a very much porous surface, so the water or moisture content easily migrate into the pores of the wood. This usually happens due to imbibition , it is diffusion where water molecules are absorbed by solids, which increases in its volume. imbibition is always towards the concentration gradients, hence solid colloid like wood absorbs water and swell in size, due to increase in size of door it gets jammed.

Bark of a tree is impervious to gases and water. Give reasons

Cells of bark are dead and compactly arranged without intercellular spaces. They have a chemical called suberin in their walls that make them impervious to gases and water. So the bark of a tree is impervious to gases and water

The process by which water enters the root hair cell is ________

The process by which water enters the root hair cell is called as osmosis. Due to the semipermeability and low potential of water, water enters into root hair through osmosis.

Differences between positive hydrostatic pressure gradient and negative hydrostatic pressure.

Positive hydrostatic pressure gradient	Negative hydrostatic pressure gradient
When the difference in pressure exerted by a fluid at a given point due to gravity is towards gravity.	When the difference in pressure exerted by a fluid at a given point due to gravity is against gravity.
In plant cells, the turgor pressure is the positive hydrostatic pressure.	In plant cells, the pressure developed in xylem and in the walls between cells is negative hydrostatic pressure.

Describe the reaction of osmosis.

Osmosis is the spontaneous net movement of solvent molecules through a selectively permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides. It may also be used to describe a physical process in which any solvent moves across a selectively permeable membrane (permeable to the solvent, but not the solute) separating two solutions of different concentrations. When a cell is submerged in water, the water molecules pass through the cell membrane from an area of low solute concentration to high solute concentration. If the cell is submerged in water, the water moves into the sucrose solution because sucrose solution has higher solution than that of water.

What is facilitated diffusion? How symport transport is different from antiport transport?

Facilitated diffusion (also known as facilitated transport or passive-mediated transport) is the process of spontaneous passive transport (as opposed to active transport) of molecules or ions across a biological membrane via specific transmembrane integral proteins. However, a symporter is an integral membrane protein that is involved in the transport of many different types of molecules across the cell membrane. The transporter is called a symporter because the molecules will travel in the same direction in relation to each other. This is in contrast to the antiport transporter.

In which condition plant cell become flacid?

This is observed when a plant cell is placed in an isotonic solution wherein the concentration of solutes in the outside is the same as that in the inside of a plant cell.

What occupies the space between the cell wall and the shrunken protoplast in the plasmolyzed cell?

The hypertonic solution (i.e. a solution with high salt concentration) occupies the space between the cell wall and shrunken protoplast in a plasmolysed cell.

State the term used for the transport of food from leaves to the other parts of a plant.

$$\textbf{Solution:}$$

$$\bullet$$ 'Translocation' is the term used to refer to the transportation of food from leaves to the other parts of a plant.

$$\bullet$$ It is the movement of sucrose and other important amino acids throughout the plant's body.

$$\bullet$$ Sucrose is formed in the leaves having green-colored chlorophyll pigment by the process of photosynthesis.

$$\bullet$$ This sucrose is the main food material which is transported to other plant parts by a vascular tissue called phloem and the process is called translocation.

$$\bullet$$ The process of translocation is an energy-consuming process and requires energy in the form of ATP molecules.

Name the process of loss of water in the form of vapour from the aerial parts of the plants.

Answer:
1.Transpiration- is the process of loss of water in the form of vapor from the aerial parts of the plants.
2.The aerial part of the plants loses water through stomatal pores.
3.The main site of the transpiration is leaves however stems also transpire.

Define Imbibition

Adsorption of liquid by any solid material is called imbibition. It is also a type of diffusion.

$$\bullet$$ Water on any other liquid which is adsorbed is known as imbibate and solid adsorbent which cause imbibition or adsorption is called imbibant.

Explain the process of translocation of food materials in plants.

Translocation occurs through part of vascular tissue known as phloem that also transports carbohydrates, amino acids and other substances such as plant hormone which are made in tips of roots and shoots to the storage and growing organs.
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Write note on

Root pressure

Root pressure can be defined as a force that helps to drive fluids upward into the water-conducting vessels. It is generated as a result of osmotic pressure in the cells of the roots and can be demonstrated by exudation of fluid when the stem is cut off just above the ground. As the stem is cut off, dops of solution begin to ooze out which is an effect of root pressure. The effect of root pressure is also visible at night and early morning. During this time the rate of evaporation is low, as a result of which water droplets can be seen around special openings of veins near the tip of leaves of plants.

Define plasmolysis.

When a plant cell is kept in a hypertonic medium, the water inside the cell moves outside due to exosmosis and this causes the cytoplasm to shrink. This phenomenon is known as plasmolysis.

when plasmolysis occurs the cell membrane of a plant cell shrinks but what happens to the cell wall i asked this question to me bio sir but he told th - Biology -

Define plasmolysis.

If a cell is placed in a solution having high concentration, then protoplasm will begin to shrink and leave the cell wall and round off. This shrinking of protoplasm is called plasmolysis.

Define the following:
Osmosis

Osmosis: It is a special form of diffusion. where two solutions of different concentrations are separated by a semipermeable membrane. In this, molecules move from a weaker solution to a stronger solution.

Define the following:
Plasmolysis

Plasmolysis: if a cell is placed in a solution having a higher concentration, then cell the water molecules will move from the cell sap to outer solution and the turgidity of the cell wall will go on decreasing and the cell wall begin to shrink This shrinking of protoplasm is called plasmolysis.

What is guttation? Explain with examples.

Guttation: The exudation of water from plants in a liquid form, by leaves is known as guttation. It takes place when environmental conditions are favourable, so, as to check transpiration, the air is very humid.
Sometimes, water oozes out of the margin of leaves of peepal, tomato, Nasturtium, lawn grass in the morning hours, and in the night in the form of minute drops. This is called guttation.
In plants that show guttation, there are special stomata, the water stomata, or hydathodes located on margin and the apex of leaves, just next to the vein ending. They open internal & into a small cavity surrounded by thin-Nailed parenchyma.
Conditions for guttation:
• Guttation increases when the absorption rate is more than the rate of transpiration.
• When there is enough humidity in the atmosphere, then guttation is more.

Explain root pressure in plants with the help of an experiment.

Water from soil reaches xylem vessels of the root. because of the osmotic pressure gradient and from there it rises up due to pressure. The pressure which causes water to rise up in xylem is called root pressure. It is a vital pressure which pushes water upwards. This is possible when cortical cells alternately pulsate. This root pressure can be understood through a simple experiment.

Experiment: Take a well-watered potted plant and cut the main stem to 7cm above the soil surface and join the cut end of the stem with a glass tube. with the help of a rubber tube joint. Fill some water in a glass tube up to the fixed mark.
Make the rubber joint airtight by applying molten wax, or grease. Keep the apparatus for an hour or so. It will be observed that water in the glass tube is rising. The rise in a glass tube is due to root pressure. which pushes up the water from root to stem. The magnitude of root pressure is not much.

What is osmosis? Explain with the help of an experiment.

Osmosis may be thought of a special type of diffusion, which involves the movement of water or other solvent molecules through a semipermeable (or differentially permeable) membrane from an area of high potential (pure solvent) to an area of low potential (more concentrated solution). In a plant cell, the absorption of water or solution from an outside atmosphere, from cell to cell takes place through the plasma membrane, which is semipermeable. The semi-permeable membrane permits the passage of solvent but restricts the movement of most of the solute particles.
Experiment to demonstrate Osmosis: Taken a small bag of cellophane. Cellophane is semi-permeable. Filled 2% sugar solution in it. In this solution, there is 2% sugar and the remaining 98% is water. Suspend the cellophane bag after tying its mouth with thread, in a beaker having pure water. The concentration of water in the beaker is 100% and the concentration of water filled up in the bag is 98%. So, water molecules will diffuse from a beaker into the bag, i.e., from high concentration to low concentration.
As a result of these, the bag will swell up because of more water coming in it. The bag will remain in the swollen position, because of the pressure generated by water filled in that bag. The diffusion of water molecules from higher concentration to lower concentration through a semi-permeable membrane is called osmosis and the pressure generated by osmosis is called osmotic pressure. Osmotic pressure helps to move water through conducting system in plants. It helps plant cells to retain water and keeping their shape and rigidity. Osmotic pressure operates the guard cells and thus, affects the opening and closing of stomata.
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In a passive transport across a membrane, when two protein molecules move in opposite direction and independent of each other, it is called as _____.

In a passive transport across a membrane, when two protein molecules move in opposite direction and independent of each other, it is called as antiport.

Explanation: Antiport is the movement of ions or molecules in opposite direction through the same transporter protein. This is a type of facilitated diffusion.

Explain plasmolysis in a plant cell. Draw a diagram showing stages in plasmolysis.

Plasmolysis: If a cell is placed in a solution having a higher concentration than the concentration of cell sap inside the cell, then by exosmosis cell sap will begin to come in external solution and cell begins to lose its turgidity and begin to shrink. In the end, the protoplasm will shrink and leave this wall and round off. This shrinking of protoplasm is called plasmolysis.
• Normal cell
• Contraction of vacuole
• Construction of plasm membrane
• Shunken round of cell.
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Define Imbibition.

Imbibition: It is a process by which the rise of water occurs, due to the attraction between water molecules and molecules of the substance. The water absorbed by a cell wall and hard seed coat is mostly through imbibition.

Define the following:
Diffusion

Diffusion: The movement of molecules in the direction of concentration gradient Le from a region of higher concentration to that of lower concentration is called diffusion. It occurs only when the concentration of the diffusing substances is not uniform.

Water moves up against gravity and even for a tree of 20m height. the tip receives water within two hours. The most important physiological phenomenon which is responsible for the upward movement of water is _____.

Water moves up against gravity and even for a tree of 20m height. the tip receives water within two hours. The most important physiological phenomenon which is responsible for the upward movement of water is transpiration pull.

Define the terms:
(a) Semi-permeable membrane
(b) Osmosis

(a) Semi-permeable membrane: The movement of solvent molecules is allowed through a membrane (e.g. water molecules) but it prevents the movement of solute particles (e.g. sugar or salt molecules).

For example - egg membrane, parchment membrane, cellophane paper, etc. are semi-permeable membranes.

(b) Osmosis: A semi-permeable membrane through which the diffusion of water molecules from a region where water is more concentrated to a region where it is less concentrated is called osmosis. In other words, osmosis is the diffusion of water from its pure state or dilute solution into a stronger or concentrated solution through a semi-permeable membrane.

Define transpiration.

Answer:

Transpiration is the evaporation of water from plants occurring at the leaves while their stomata are open for the passage of CO2 and O2 during photosynthesis.

It is the process in which plants release the water inside it in the form of moisture or water vapor. Roots consume some amount of water from the soil and the rest evaporates in the atmosphere.

Transpiration creates a pull for absorption and translocation of water as well as minerals. Due to the process of transpiration, there is pressure on the plant for the absorption of water. Therefore, the process of transpiration is called a necessary evil.

Given below is a table. Fill in the gaps.
Property simple diffusion facilitated transport Active Transport
Property Simple diffusion Facilitated transport Active transport
Highly selective ___ Yes _
Uphill transport _ _ Yes
Requires ATP
_ _ ___

Property	Simple diffusion	Facilitated transport	Active transport
Highly selective	No	Yes	Yes
Uphill transport	No	No	Yes
Requires ATP	No	No	Yes

Define water potential and solute potential.

The kinetic energy of water is called water potential. Water potential reduces when a solute is dissolved in it. The magnitude of lowering of water potential because of solute is called solute potential.

If one wants to find minerals and in the form. they are mobilised in the plant. How will an analysis of the exudate help?

An Analysis of xylem exudates helped in recognizing the forms and ways in which minerals are transported in plant. For example; the analysis of xylem exudates has revealed that most of the Nitrogen Is transported In the form of organic molecules rather than in the form of inorganic molecules. Small amounts of Phosphorus and Sulphur are transported in the form of organic compounds. Some exchange of materials also takes place between xylem and phloem. So, it cannot be clearly said that xylem transports only inorganic compounds and phloem transports only organic compounds.

Define Uniport, Symport and Antiport. Do they require energy?

Some carrier proteins allow movement only when two types of molecules move together. Based on this criterion, such a movement can be of three types:
(a) Uniport: When only one molecule moves across a membrane through the transporter protein this is called uniport.
(b) Antiport: When both types of molecule move in mutually opposite directions; this is called antiport.
(c) Symport: When both types of molecule move in the same direction; this is called symport.
These are types of facilitated diffusion and hence do not require energy.

Water molecule is very polar. Polar end of molecule attracts opposite charges on another water molecule (acts like magnet). How will you explain this property of water with reference to upward movement of water? Comment on the upward movement of water given the intermolecular hydrogen bonding in water.

Water is a polar molecule. When two water molecules approach one another, the slightly negatively charged oxygen atom of one forms a hydrogen bond with a slightly positively charged hydrogen atom in the other. This attractive force, along with other intermolecular forces, is one of the principal factors responsible for the occurrence of surface tension in liquid water. It also allows plants to draw water from the root through the xylem to the leaf.
Cohesion between water molecules helps In making a continuous column of water in xylem. This along with adhesion and surface tension helps the transpiration pull to pull up the water column in plants. Thus, a multitude of factors are at work during ascent of sap in plants.

Differentiate between Apoplast and Symplast pathways of water movement. Which of these would need active transport?

Apoplast Pathway	Symplast Pathway
(i) The apoplastic movement of water occurs exclusively through the intercellular spaces and the walls of the cells.	(i) The symplastic movement of water occurs through the cells-their cytoplasm, intercellular movement is through the plasmodesmata.
(ii) The apoplast pathway does not provide any barrier to water movement.	(Ii) The symplast pathway provide a little barrier to water movement.
(iii) It consists of the non-living parts of the plant body.	(iii) It consists of living parts of the plant body.
(iv) Movement of water in this pathway is faster.	(iv) Movement of water In this pathway is relatively slower.

None of these pathways need active transport.

Differentiate between active and passive absorption of minerals.

Difference between active and passive transport of minerals is as follows

Passive Absorption of minerals	Active Absorption of minerals
1. Ions are absorbed along their electrochemical gradient.	1. Ions are accumulated against their electrochemical gradient.
2. In this process metabolic energy of cell is not used in movement of ions.	2. In this process metabolic energy (ATP) is used in movement of ions.

Name the scientist(s) who proposed the principle of active $$K^+$$ transport.

The theory of active $$K^+$$ uptake was proposed by Imamura and Fujino (1959) and modified by Levitt (1974).

Write a note on guttation.

Water loss in the form of small droplets from hydathodes situated on the tip and margin of leaves is called guttation.

Guttation:

De Barry (1869) first observed this process.
Exudation of droplets of water from the tips and margins of leaves is called guttation.
This loss occurs through minute openings found at the terminal ends of the veins of leaves of some plants. These openings are called hydathodes.
The pore of hydathode is called water pore and is an incompletely differentiated stoma.
These are permanently open pores because the two cells surrounding the pore are incapable of movement.
A group of thin-walled loosely arranged parenchyma cells is present below the hydathode. This is called epithem.
The tracheary elements of veins terminate or end just close to the epithem tissue.
When water absorbed by roots exceeds transpiration, root pressure develops and water from xylem vessels and tracheids is pushed in the epithem tissue.
Finally, water is exuded out in the form of droplets through the pore. Thus guttation is an expression of root pressure.
Guttation takes place more during the night and early morning hours. Eg. Tomato, grasses, Potato, Bryophyllum, Colocasia etc.
The fluid lost in guttation is not pure water but contains dissolved minerals and some organic substances also.
Deposition of minerals and organic substances on the surface of leaves may result in injurious effect and may provide a medium for a pathogenic attack.

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What are the factors affecting the rate of diffusion?

Diffusion is the passive movement of substances from a region of higher concentration to a region of lower concentration.

Explanation:

Factors affecting Rate of diffusion are:

(i) Density- rate of diffusion is inversely proportional to square root of it’s relative density i.e. rate of diffusion decreases with density of the medium.

(ii) Temperature- rate of diffusion increases with increase in temperature.

(iii) Pressure gradient- rate of diffusion is directly proportional to the difference of pressure at the two ends of the system such that with increase in difference of pressure, the rate of diffusion increases.

(iv) Distance- rate of diffusion is inversely proportional to the distance between the two ends of the system.

E.g., Diffusion may be fast from root hairs to lower parts of stem but might slow down to higher parts of stem or leaves in absence of other forces.

What happens when a pressure greater than the atmospheric pressure is applied to pure water or a solution?

Explanation:

If the application of pressure is more than atmospheric pressure, the water potential of pure water or a solution increases.
Example: When diffusion of water into a plant cell takes place, pressure builds up against the cell wall. This makes the cell wall turgid.

Differentiate between the following:
(a) Diffusion and Osmosis
(b) Transpiration and Evaporation
(c) Osmotic Pressure and Osmotic Potential
(d) Imbibition and Diffusion
(e) Apoplast and Symplast pathways of movement of water in plants.
(f) Guttation and Transpiration.

(a) Diffusion and Osmosis

Diffusion	Osmosis
1. Diffusion is the passive movement of particles, ions, and molecules along the concentration gradient.	1. Osmosis is the process in which the diffusion of a solvent (water) occurs across a semi-permeable membrane.
2. It can occur in solids, liquids, and gases.	2. It occurs in the liquid medium.
3. It does not require a semi-permeable membrane.	3. It requires a semi-permeable membrane.

(b) Transpiration and Evaporation

Transpiration	Evaporation
1. It occurs in plants.	1. It occurs from any free surface and involves living and non-living surfaces.
2. It is a physiological process.	2. It is a physical process.
3. It occurs mainly through the stomatal pores on plant leaves.	3. It is occurs through any free surface.
4. It is controlled by environmental factors as well as physiological factors of plants such as root-shoot ratio and number of stomata.	4. It is entirely driven by environmental factors.

Osmotic pressure	Osmotic potential
1. It is expressed in bars with a positive sign.	1. It is expressed in bars with a negative sign.
2. It is a positive pressure.	2. It is a negative pressure.
3. Its value increases with an increase in the concentration of solute particles.	3. Its value decreases with an increase in the concentration of solute particles.

(d) Imbibition and Diffusion:

Imbibition	Diffusion
1. Imbibition is a special type of diffusion. In this process, water is absorbed by solids and colloids, causing an enormous increase in volume.	1. Diffusion is the passive movement of particles, ions, and molecules along the concentration gradient.
2. It usually involves water.	2. It involves solids, liquids, and gases.

(e) Apoplast and Symplast pathways of water in plants

Apoplast pathway	Symplast pathway
1. The apoplast pathway involves the movement of water through the adjacent cell walls of the epidermis and cortex. The movement of water is restricted at the casparian strips of the root endodermis.	1. The symplast pathway involves the movement of water through the interconnected protoplasts of the epidermis, cortex, endodermis, and root pericycle.
2. It is a faster process of water movement and water moves through mass flow.	2. It is a slower process of water movement.

(f) Guttation and Transpiration

Guttation	Transpiration
1. It occurs usually at night.	1. It occurs usually during the day.
2. Water is lost from the leaves in the form of liquid droplets.	2. Water is lost from the leaves in the form of water vapour.
3. It occurs through the vein endings of leaves.	3. It occurs through the stomata.
4. It is an uncontrolled process.	4. It is a controlled process.

Explain why pure water has the maximum water potential.

Water potential quantifies the tendency of water to move from one part to the other during various cellular processes. It is denoted by the Greek letter Psi or Ψ. The water potential of pure water is always taken as zero at standard temperature and pressure.

It can be explained in terms of the kinetic energy possessed by water molecules. When water is in liquid form, the movement of its molecules is rapid and constant. Pure water has the highest concentration of water molecules. Therefore, it has the highest water potential. When some solute is dissolved in water, the water potential of pure water decreases.

(a) With the help of well-labelled diagrams, describe the process of plasmolysis in plants, giving appropriate examples.
(b) Explain what will happen to a plant cell if it is kept in a solution having higher water potential.

(a) Plasmolysis can be defined as the shrinkage of the cytoplasm of a plant cell, away from its cell wall and toward the centre. It occurs because of the movement of water from the intracellular space to the outer-cellular space. This happens when the plant cell is placed in a hypertonic solution (i.e., a solution having more solute concentration than the cell cytoplasm). This causes the water to move out of the cell and toward the solution. The cytoplasm of the cell shrinks and the cell is said to be plasmolysed. This process can be observed in an onion peel kept in a highly concentrated salt solution.

(b) When a plant cell is placed in a hypertonic solution or a solution having higher water potential, the water diffuses into the cell (i.e., the movement is observed from higher to lower water pressure region). The entry of water in the plant cell exerts pressure on the rigid cell wall. This is called turgor pressure. As a result of its rigid cell wall, the plant cell does not burst.

Carry out the following osmosis experiment:

Take four peeled potato halves and scoop each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in a trough containing water. Now,

(a) Keep cup A empty.
(b) Put one teaspoon sugar in cup B.
(c) Put one teaspoon salt in cup C.
(d) Put one teaspoon sugar in the boiled potato cup D.

Keep these for two hours. Then observe the four potato cups and answer the following:

(i) Explain why water gathers in the hollowed portion of B and C.
(ii) Why is potato A necessary for this experiment?
(iii) Explain why water does not gather in the hollowed-out portions of A and D.

Answer-

(i) Since sugar and salt were present in B and C respectively, water from the trough gathered in the hollowed portions of potato in B and C by the process of osmosis.

(ii) Potato A is necessary for carrying out this experiment because it acts as a control experiment. Control helps us to check what changes occurred during the course of the experiment and helps us to compare the results.

(iii) Water does not gather in the hollowed portion of potato A as it was empty. Water also does not gather in cup D because the potato used was boiled which makes it inactive as after boiling its protein structure were denatured, resulting in the disruption of the cell membrane.

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Briefly explain the following terms.
(i) Genes
(ii) Cytokinesis in plant cells
(iii) Guttation
(iv) Diabetes insipidus
(v) Disinfectants

(i) Genes : Genes are units of heredity that determine particular traits. These are the small segments of DNA. They encode for certain proteins which are responsible for characters. (e.g., colour of hair, blood group, colour of eye etc.)

(ii) Cytokinesis in plant cells : Cells in multicellular plants do not have centrioles. The division of cytoplasm occurs by the formation of a new cell wall in the equatorial region at the end of anaphase. In telophase, new cellulose particles are gradually deposited in the equatorial zone. The particles extend on either side, from the centre towards the periphery (centrifugal) until it completely divides the cell. These particles fuse together to form a delicate plate membrane.

(iii) Guttation : The loss of water in the form of water droplets along the margins of leaves through hydathodes. It takes place due to increased hydrostatic pressure that builds up within the cells. The wall pressure that develops in fully turgid parenchymatous cells force the water out.

(iv) Diapedes insipidus : The condition occurs due to lesser secretion of vasopressin (Anti-diuretic hormone) from the posterior lobe of pituitary gland. The disease is characterized by excretion of large amounts of urine and subsequent dehydration and thirst. No sugar or albumin is present in the urine. A person with severe diabetes insipidus may die due to dehydration if deprived of water for few days.

(v) Disinfectants : These are powerful chemical substances used for destroying microbes in spots, places for sterilizing operation theatres and surgical instruments. They are not applied on the body due to their strong corrosive nature eg. Cresol, Phenol, Lysol, DDT etc.

Define the term water potential. What are its components? Explain.

Water potentialis defined as the difference between chemical potential of water at any point in a system and that of pure water under standard conditions. It is designated by sign Psi (ψ).

There are three major components of water potential in a plant cell. These are: (a) Matrix potential, (b) Solute potential and (c) Pressure potential.

Matrix potential (ψ$$_m$$) is the component of water potential which is determined by the attraction between hydrated colloidal molecules, cell wall etc., and water.

Solute potential (ψ$$_s$$) is also known as the osmotic potential. It may be defined as the amount by which water potential is always represented in negative numbers.

Pressure potential (ψp) is represented by the cell wall and cell membrane. The cell wall exerts a pressure (WP) on the cell contents. Similarly the cell membrane also exerts a pressure (ψ$$_p$$) on the cell wall by virtue of its solvent content. The pressure potential is positive.

ψ=ψ$$_m$$+ψ$$_s$$+ψ$$_p$$

Explain plasmolysis and bring out its significance.

Plasmolysis is defined as the process of contraction or shrinkage of the protoplasm of a plant cell and is caused due to the loss of water in the cell.

In the process of pickling salt is added as the preservatives for food like jams, jellies, and pickles. The cells lose water due to higher concentration outside and become less conducive to support the growth of microorganisms.

What is meant by facilitated transport?

Facilitated diffusion:--It is a type of diffusion in which the molecules move from the areas of higher concentration to areas of lower concentration assisted by a transporter protein,
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In passive transport method, transport of molecules takes place --------- the concentration gradient.

In passive transport method, transport of molecules takes place along the concentration gradient.

-There is no need of ATP in the passive transport.

Define symport and antiport.

$$\textbf{Solution}$$

$$\bullet$$ Symport:-

Symport is the type of transport in which two different molecules can move through a membrane in same direction by using a common carrier mechanism.
The transporter is called a symporter which is an integral protein and it works in the cell membrane the molecules to transport across the membrane at the same time.
One of the example is moving a glucose up its concentration gradient with the help of the energy from the movement of sodium ions that are moving down their concentration gradient.

$$\bullet$$ Antiport:-
Antiport is a type of transport in which two different molecules can move through a membrane in opposite directions.
It is also a mechanism for the coupled transport in which the molecules move in different directions.
The transporter is an antiporter which is also a integral membrane protein.
One of its example is the transport of two species of solutes in opposite direction across a membrane.

Give a scientific term for each of the following.
(i) A single isolated contraction of muscle fibre.
(ii) Inhibition of the growth of the lateral bud by terminal bud.
(iii) Specialised structure through which guttation occurs.
(iv) Development of embryo from the egg without the process of fertilization.
(v) Process of splitting of water molecules during photosynthesis.
(vi) Passing out of urine.

$$(i)$$ The scientific term for a single isolated contraction of muscle fibre is called a single muscle twitch.

$$(ii)$$ The scientific term for the inhibition of lateral bud growth by terminal bud is called apical dominance.

$$(iii)$$ The scientific term for the specialised structure through which guttation occurs is called hydathode.

$$(iv)$$ The scientific term for the development of embryo from the egg without the process of fertilization is called parthenogenesis.

$$(v)$$ The scientific term for the process of splitting of water molecules without the process of fertilization is called photolysis of water.

$$(vi)$$ The scientific term for the passing out of urine is called micturition.

Define : Tyndall effect / Brownian movement / Imbibition / Diffusion / DPD / Osmosis / Hypertonic solution / Hypotonic solution / Isotonic solution / Plasmolysis / Osmotic pressure / Turgor pressure / Wall pressure / Water potential / Permeability.

Diffusion: It is the random movement of molecules along the concentration gradient (from an area of higher concentration to an area of lower concentration) by their kinetic energy. It is a spontaneous and passive process.

Osmosis: It is a specialized case of diffusion that involves the passive transport of water (i.e. solvent ).In osmosis, water moves through a semipermeable membrane from a region of its higher concentration to a region of its lower concentration.

Turgor Pressure: When a plant cell is placed in a hypotonic solution, water diffuses into the cell causing the protoplast to build up a pressure against the wall. The pressure extended outwardly against the cell wall by the expanding protoplast is known as Turgor pressure.

Wall pressure: An equal but opposite inward pressure by the cell wall on protoplast is called wall pressure.

Plasmolysis: The shrinkage of the cytoplasm of a living cell as a result of exosmosis is known as plasmolysis.

Osmotic pressure: It is defined as the pressure required to completely stop the entry of water into an osmotically active solution across a semipermeable membrane. It is also defined as the minimum pressure needed to stop osmosis.

Water potential: It is the measure of the free energy of water per unit volume. It is commonly expressed in terms of pressure units such as Pascal.

Permeability: It is the property of the membrane to allow the passage of both solute and solvent molecules.

Tyndall effect: It is the phenomenon in which the particles in a colloid scatter the beams of light that are directed at them. This effect is seen by all colloidal solutions and a few very fine suspensions. The intensity of scattered light depends on the density of the colloidal particles as well as the frequency of the incident light.

Brownian movement: Brownian movement also called Brownian motion is defined as the uncontrolled movement of particles in a fluid due to their constant collision with other fast-moving molecules.

Imbibition: Imbibition is a type of diffusion where the water is absorbed by the solid particles called colloids, causing an enormous increase in volume. The solution is not formed in the process. In other words, water absorption by colloids is known as imbibition.

Hypertonic solution: A hypertonic solution has higher solute content than another solution. When a plant cell is placed in a hypertonic solution, water moves out and protoplast shrinks and cells become flaccid.

Hypotonic solution: A solution with a lower solute content than another solution is referred to as a hypotonic solution. When a plant cell is placed in a hypotonic solution, water enters into the cell protoplast and the cell becomes turgid.

Isotonic solution: An isotonic solution has the same solute content as another solution. When a cell is placed in an isotonic solution, there is no net flow of water towards the inside or outside.

DPD: DPD stands for Diffusion Pressure Deficit (DPD). It is the amount by which the diffusion pressure varies between two solutions. This is characterized as the amount by which the water or solvent diffusion pressure in a solution is inferior to that of pure water or solvent.

Water potential: The water potential is defined as the measure of free energy per volume. It is used to describe the direction of the movement of water.

Define Diffusion/ Osmosis ?

Osmosis-

Osmosis is movement of solvent particles across a semipermeable membrane from a dilute solution to concentration solution.

Diffusion:

Diffusion is the movement of particles from the area of higher concentration to the area of lower concentration.

A candidate in order to study the process of osmosis has taken 3 potato cubes and put them in 3 different beakers containing 3 different solutions. After 24 hours, in the first beaker the potato cube increased in size, in the second beaker the potato cube decreased in size and in the third beaker there was no change in the size of the potato cube. The following diagram shows the result of the same experiment:

Give the technical terms of the solutions used in beakers,2 and 3.

The technical terms for the solution in the beaker are

1. Hypotonic (the potato cube increased in size, concentration of solutes more in the cell than in the solution.)
2. Hypertonic (the potato cube decreased in size, concentration of solutes more in the solution than in the cells)
3. Isotonic (the size of the potato cube remained unchanged, the solute concentration is same in the cells as well as the solution)

Differentiate between the following:
(a) Turgor pressure and wall pressure
(b) Imbibition and osmosis

Turgor pressure	Wall pressure
It is the pressure applied by the content of the cell against the cell wall.	It is the pressure applied to the cell wall on the contents of the cell.
It helps the growth and enlargement of plant cells.	It does not help to keep plant erect.
It is a hydrostatic pressure.	It exerts opposite pressure against the turgor pressure.

Imbibition	Osmosis
It is the process of absorption of water or solvent by the solid surface.	It is the process of movement of water from higher chemical potential to lower chemical potential.
Heat is produced.	Heat is not produced.
It requires presence of colloidal particles.	It requires presence of solute particles.
Semipermeable membrane is not required.	Semipermeable membrane is essential.

Differentiate between
Hygroscopic Water and capillary Water.

Hygroscopic water occurs in the form of thin films around the colloidal soil particles. Whereas the water that is retained in minute interstitial spaces in the form of thin films surrounding the soil particles, is known as capillary water. Hygroscopic Water retained even when whole of the capillary water is lost from the soil.

In the given diagram, which cell has maximum absorbing capacity?

The cell having low water potential will absorb the maximum amount of water from the neighboring cells having high water potential.
This happens because water always moves from a region of higher Ψw to one with lower Ψw.
Cell A $$Ψ_w$$ = $$Ψ_s$$ + $$Ψ_p$$ = -9 + 6 = -3 bars.
Cell B $$Ψ_w$$ = -9 + 3 = -6 bars.
Cell C $$Ψ_w$$ = -12 + 10 = -2 bars.
Cell D $$Ψ_w$$ = -18 + 16 = -2 bars.
Therefore, cell C and D will have the maximum absorbing capacity.

Give the direction for the flow of water in the given diagram.

Water potential (Ψ) is determined by two factors - osmotic (or solute) potential (ΨS) and pressure potential (ΨP).
The formula for calculating water potential is $$Ψ_w$$ = $$Ψ_s$$+$$Ψ_p$$.
Osmotic potential is directly proportional to the solute concentration.
Cell A has $$Ψ_w$$ = -9 bars.
Cell B has $$Ψ_w$$ = $$Ψ_s$$+$$Ψ_p$$ i.e -12 + 7 = -5bars.
Cell C has $$Ψ_w$$ = -18 +13 = -5 bars.
Water always moves from a region of higher Ψw to one with lower Ψw.
Therefore, water will move out from cell B and C (they have the same water potential) into cell A (less water potential).

If one chamber has a $$\Psi_w $$ of - 2000 kPa, and the other - 1000 kPa, which is the chamber that has the higher $$\Psi $$ ?

Water potential (Ψ) is a measure of how freely water molecules can move in a particular system. Ψ is never positive but has a maximum value of zero, which is that of pure water at atmospheric pressure.
Impure water or water that has solutes in it has a negative water potential value. The more solute there is, the more negative Ψ becomes since the solute molecules will attract the water molecules and restrict their freedom to move.
Here chamber A with Ψw of - 1000 kPa has a higher Ψ than the other with Ψw of - 2000 kPa.

Differentiate Between
Osmotic potential and matrick potential

a) Osmotic potential - It is the potential water molecules to form a hypotonic solution to a hypertonic solution across a semi-permeable membrane. It is also known as solute potential and is a measure of water potential for movement from a region of lower solute concentration to higher solute concentration.

b) Matric potential - Matric potential is a consequence of the binding of water to materials such as soil particles, cellulose and proteins and the enclosure of water in capillaries or other fine pores. It is defined as the portion of water potential that can be attributed to the attraction of the soil matrix for water.

It is measured by tensiometer.

What will happen if dry kidney beans are left in pure water for sometime?

If dry kidney beans are left in pure water for sometime they imbibe water by process called osmosis (movement of solvent through a semipermeable membrane from a less concentrated solution into a more concentrated one). The beans swell by imbibing water.

What will happen if a deshelled egg is kept in saline water?

Deshelled eggs can be prepared by placing the egg in dilute HCL acid for 10 hours by which shell will be dissolved and egg be covered with only semipermeable membrane. When this is semipermeable egg is placed in a saline solution (hypertonic solution), exosmosis occurs and the egg shrinks due to loss of water to the surrounding environment. If the water concentration inside is higher than the surrounding environment, the medium is said to be hypertonic solution. Here, the number of water molecules diffusing out due to exosmosis will be more than the molecules entering the cell.

Study the experimental set up in figure and then answer the questions that follow:
a) What phenomenon is being studied by this set up?
b) Explain the phenomenon mentioned in (a) above
c) What is meant by 'semipermeable' membrane?
d) What will you observe in the set up after about half an hour? Give a reason for your answer.

a - Osmosis is the phenomenon that is studied here.

b- Osmosis is the phenomenon where pure water flows from a dilute solution through a semi-permeable membrane to a concentrated solution.

c- Semipermeable membrane is the membrane that will allow only some molecules to pass through it and block other molecules.

d- After half an hour we will observe equilibrium as a result of osmosis.

In part A there is 10 % sucrose solution and in part B there is 5% sucrose solution , so water will flow from B to A as water moves from hypotonic to hypertonic solution, until it reaches equilibrium.

How does the pressure extend by a liquid change with the depth?

The pressure exerted by a liquid increases with depth. This is due to an increase in hydrostatic pressure, the force per unit area exerted by a liquid on an object. As you go deeper, the area of liquid exerting pressure increase thus it also increases the pressure.

Describe pressure potential.

$$\textbf{Solution}$$

$$\bullet$$ The pressure potential is also known as water potential which is the hydrostatic pressure that is exerted on the water which is present in the cell.

$$\bullet$$ Pressure potential increases when the turgidity of the cell increases. It is usually positive but sometimes it is negative in the xylem as the water pulled through the system and transported to various parts of the plant.

$$\bullet$$ In plasmolyzed cell the pressure potential is almost zero there will be no pressure exerted by the protoplast against the cell wall.

You soak seeds of bean and observe them after 2-3 days. What will he your observations?

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Draw a flowchart to show the breakdown of glucose by various pathways.

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Why Is solute potential always negative? Explain $$y_w = y_z + y_p$$

When a solute is dissolved in water, it reduces the water potential because concentration of water in a solution Is less than that in pure water. The measure of reduction in water pollution because of solute is called solute potential. Since, solute potential always has a negative impact on water potential, so its value is always negative.
For a solution at atmospheric pressure, its water potential is equal to solute potential. When a pressure greater than atmospheric pressure is applied, then water potential of the solute increases. This is Illustrated by following equation:
$$y_w = y_z + y_p$$
Here; $$y_w$$ is water potential, $$y_s$$ is solute potential and $$y_p$$ is pressure potential.

(a) An outline sketch of a tree is shown in the diagram below. Study the same and answer the questions that follow:
(i) Name the phenomenon that is labelled A in the diagram.
(ii) Explain the phenomenon occurring in A.
(iii) What is the importance of this phenomenon in plants?
(iv) Explain the role of any three external factors that will increase the rate of the phenomenon.
(v) What do the direction of arrows in B and C indicate?

Answer-

1. Transpiration

2. Transpiration is the process of evaporation of water from aerial parts like leaves, and stems.

Roots consume some amount of water from the soil and the rest evaporates in the atmosphere. Parts of plants such as stems, small pores on leaves, and flowers evaporate the water into the atmosphere. In other words, it is the process in which water evaporates in the atmosphere from plant leaves and other parts.

3. It helps in water transport, cools the plant and maintains turgidity of the cells.

4. Factors that increase transpiration:

A. Temperature.

B. Air movement.

C. Light intensity.

5. Water movement in plants is through osmosis from the roots to the stems and other aerial parts is indicated by the arrow.

Transport In Plants - Class 11 Medical Biology - Extra Questions

Differentiate between absorption and adsorption.

Loss of water as droplets from the margins of certain leaves is called ?

Differentiate between Guttation and bleeding.

Differentiate between guttation and bleeding in plants.

Osmosis is a special kind of diffusion, in which water diffuses across the cell membrane. The rate and direction of osmosis depends upon both _____.

The $$C_4$$ plants are twice as efficient as $$C_3$$ plants in terms of fixing $$CO_2$$ but lose only as much water as $$C_3$$ plants for the same amount of $$CO_2$$ fixed.

Diffusion is a slow process and is not dependent on a system. Why?

What are apoplast and symplast?

Osmosis is an example of active transport. True or False? Explain.

"Transpiration is necessary evil". Explain.

Which process takes place in the water purifier?

Give reasons for this sentence:A plant cell when kept in a hypertonic salt solution for about $$30$$ minutes turns flaccid.

Differentiate between.Facilitated diffusion and active transport

Explain the symplastic movement and apoplastic movement of water in the cell.

Why do molecules diffuse down their concentration gradients?

The water potential of pure water changes when solute is added to it

Define chemiosmosis.

Define guttation.

What is imbibition?

Briefly explain the following:i) Osmosisii) Alleleiii) Pulseiv) Reflex actionv) Synapse

Which of the following has highest water potential ? (i) 1 M Salt solution (ii) 1 M Sugar solution (iii) Distilled water (iv) 1 M Sugar solution with 2-3 bars pressure

In an experimental set-up, a dye was placed at the bottom of a beaker filled with water as shown in figure A, below. After some time, the entire water in the beaker got coloured uniformly, as shown in figure D.(a) Name and define the phenomenon shown in the experiment.

Differentiate betweenWater potential and diffusion pressure deficit.

Fill in the blanks :The water potential of pure water is ...............

What would be $$\Psi _p$$ of a flaccid cell?

Describe Uniporter Catalyzed Transport ?

When separated by a semipermeable membrane, water enters the sugar solution. What would you call the sugar solution as osmotically active or inactive?

Explain an activity to show that stem conducts water and other substances.

Distinguish uniport transport method from passive diffusion ?

What will happen if a plant cell is kept in solution of higher water potential?

A plant is transpiring rapidly. Will it show root pressure also?

What would be $$\Psi _p$$ of a plasmolysed cell ?

Compare the imbibing capacities of pea and wheat seeds.

How does carbon dioxide diffuse in submerged plants?

i) Solution of 'A' chamber has higher $$Psi$$ W.ii) Solution of 'B' chamber has higher $$Psi \, s$$iii) At equilibrium 'A' chamber will have lower $$Psi \,w$$iv) Osmosis occurs in A $$\rightarrow$$ B direction. How many above conclusions are incorrect with respect to given set up ?

What is root pressure? How is it useful to plants?

State four differences between transpiration and guttation.

Write about respiration in mangroves that grow in marshylands.

Doors of house swell up in the rainy season due to what reasons?

Transpiration is a necessary evil. Justify.

The phenomenon by which living or dead plant cells absorb water by surface attraction.

The bending movements of certain flowers towards the sun and the sleep movements of certain plants at night are examples of ..................

What is root pressure?

What is the water potential value of pure water? If $$5$$ grams of sodium chloride is added, what will happen to its water potential value?

Define and explain water potential

Why do dry seeds imbibe water when placed in it?

Describe an activity to show the effect of low pressure and particulate nuclei over water vapours?

Briefly describe water potential. What are the factors affecting it?

Explain what will happen to a plant cell, if it is kept in a solution having higher water potential.

What is osmosis?

Define:(i) Radial vascular bundle (ii) Rigor mortis (iii) Root pressure

Explain the process of guttation with diagram.

The movement of water molecule from a region of higher concentration to a region of its lower concentration through a semi permeable membrane is called Osmosis.a) In the above statement, how will you differentiate active transport from passive transport ?

Soil provides water and .............. to plants.

The loss of water in the form of droplets from the margins of leaves is called as what?

What is transpiration?

Match the columns :

Explain what will happen to a plant cell if it is kept in a solution having higher water potential?

What are the factors that affect the rate of diffusion ?

Why is energy required to develop root pressure?

Define osmosis.

What is water potential? Why is it negative in value?

Name the pores through which guttation occurs.

In an osmotic system, one chamber has a $$\Psi $$ of -1000 kPa while the other has -500 kPa. Which chamber has higher water potential ($$\Psi_w$$)?

Define transpiration. Name the types of transpiration. Give the mechanism of transpiration giving V.S. of leaf.

Set up an experiment to demonstrate root pressure.

The diagram given below represents a plant cell after being placed in a strong sugar solution. Study the diagram and answer the questions that follow:How can the above cell be brought back to its original condition? Mention the scientific term for the recovery of the cell.

The diagrams given below represent the relationship between a mouse and a physiological process that occurs in green plants. Study the diagrams and answer the questions that follow:Why did the mouse die in bell jar $$B$$?

The diagram given below represents a plant cell after being placed in a strong sugar solution. Study the diagram and answer the questions that follow:What is the state of the cell shown in the diagram?

An experiment was set up as shown in the figure below. After some time, the water level in test tube A fell down but not in test tube B.Why was there a fall in the water level of test tube A and not in that of test tube B?

What is guttation? Explain with the help of diagram of the vertical section of hydathode present on apical part of tomato or primula leaf.

Fill in the blank by choosing the correct alternative from those given in brackets.When placed in a more concentrated solution, the cell contents will ............... (shrink/swell up)

Give appropriate biological or technical terms for the following.Movement of molecules of a substance from their higher concentration to lower concentration when they are in direct contact.

Differentiate between Turgidity and Flaccidity.

The process by which the intact plant loses water in the form of droplets is called

How you can demonstrate the phenomenon of osmosis in the laboratory?

Differentiate between osmosis and imbibition.

Demonstrate the phenomenon of transpiration.

Define the term plasmolysis.

Give reasons for this sentence:
A plant cell when kept in a hypertonic salt solution for about $$30$$ minutes turns flaccid.

Differentiate between.
Facilitated diffusion and active transport

Briefly explain the following:
i) Osmosis
ii) Allele
iii) Pulse
iv) Reflex action
v) Synapse

Which of the following has highest water potential ?
(i) 1 M Salt solution
(ii) 1 M Sugar solution
(iii) Distilled water
(iv) 1 M Sugar solution with 2-3 bars pressure

In an experimental set-up, a dye was placed at the bottom of a beaker filled with water as shown in figure A, below. After some time, the entire water in the beaker got coloured uniformly, as shown in figure D.
(a) Name and define the phenomenon shown in the experiment.

Differentiate between
Water potential and diffusion pressure deficit.

Fill in the blanks :
The water potential of pure water is ...............

i) Solution of 'A' chamber has higher $$Psi$$ W.
ii) Solution of 'B' chamber has higher $$Psi \, s$$
iii) At equilibrium 'A' chamber will have lower $$Psi \,w$$
iv) Osmosis occurs in A $$\rightarrow$$ B direction.
How many above conclusions are incorrect with respect to given set up ?

Define:
(i) Radial vascular bundle (ii) Rigor mortis (iii) Root pressure

The movement of water molecule from a region of higher concentration to a region of its lower concentration through a semi permeable membrane is called Osmosis.
a) In the above statement, how will you differentiate active transport from passive transport ?

The diagram given below represents a plant cell after being placed in a strong sugar solution. Study the diagram and answer the questions that follow:
How can the above cell be brought back to its original condition? Mention the scientific term for the recovery of the cell.

The diagrams given below represent the relationship between a mouse and a physiological process that occurs in green plants. Study the diagrams and answer the questions that follow:
Why did the mouse die in bell jar $$B$$?

The diagram given below represents a plant cell after being placed in a strong sugar solution. Study the diagram and answer the questions that follow:
What is the state of the cell shown in the diagram?

An experiment was set up as shown in the figure below. After some time, the water level in test tube A fell down but not in test tube B.
Why was there a fall in the water level of test tube A and not in that of test tube B?

Fill in the blank by choosing the correct alternative from those given in brackets.
When placed in a more concentrated solution, the cell contents will ............... (shrink/swell up)

Give appropriate biological or technical terms for the following.
Movement of molecules of a substance from their higher concentration to lower concentration when they are in direct contact.

Give biological reasons for the following:
A closed can of dried seeds bursts open if some water enters it by accidents.

Give reasons for the following:
Plasmolysis occurs in plant cells only and not in animal cells.

Write note on

Root pressure

Define the following:
Osmosis

Define the following:
Plasmolysis

Define the following:
Diffusion

Define the terms:
(a) Semi-permeable membrane
(b) Osmosis

Given below is a table. Fill in the gaps.
Property simple diffusion facilitated transport Active Transport
Property Simple diffusion Facilitated transport Active transport
Highly selective ___ Yes _
Uphill transport _ _ Yes
Requires ATP
_ _ ___

Differentiate between the following:
(a) Diffusion and Osmosis
(b) Transpiration and Evaporation
(c) Osmotic Pressure and Osmotic Potential
(d) Imbibition and Diffusion
(e) Apoplast and Symplast pathways of movement of water in plants.
(f) Guttation and Transpiration.

(a) With the help of well-labelled diagrams, describe the process of plasmolysis in plants, giving appropriate examples.
(b) Explain what will happen to a plant cell if it is kept in a solution having higher water potential.

Briefly explain the following terms.
(i) Genes
(ii) Cytokinesis in plant cells
(iii) Guttation
(iv) Diabetes insipidus
(v) Disinfectants

Differentiate between the following:
(a) Turgor pressure and wall pressure
(b) Imbibition and osmosis

Differentiate between
Hygroscopic Water and capillary Water.