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CBSE Questions for Class 11 Medical Biology Transport In Plants Quiz 13 - MCQExams.com
CBSE
Class 11 Medical Biology
Transport In Plants
Quiz 13
For a solution at atmospheric pressure kept in a beaker:-
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$$\Psi_w = \Psi_p$$
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$$\Psi_w = \Psi_s + \Psi_p$$
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$$\Psi_w = \Psi_s$$
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$$\Psi_w = \Psi_w - \Psi_p$$
Explanation
Water potential is the pressure developed due to the movement of water molecules. This may create hydrostatic pressure in the cells which may be positive or negative and create tension or turgor pressure in the cell. When the solution is kept at atmospheric pressure, there is no change in the hydrostatic pressure thus pressure potential (Pressure on the wall due to turgor pressure) will be equal to zero. Hence, the water potential will be equal to the solute potential (osmotic potential due to solute concentration) as there is no movement of water outside the cell.
So, the correct option is '
Ψ$$_w$$ =
Ψ$$_s$$'.
Density of vitreous humour is equal to the?
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Air
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Water
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Lens
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None of these
Explanation
The gel-like fluid present in the eye between the lens and the retina is known as the vitreous humor. It has a density of 1.022 g/cm3 which is almost equivalent to that of water (1 g/cm3).
So, the correct answer is 'Water'.
Correct expression for water potential of plasmolysed cell will be
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$$\Psi_w = \Psi_s$$
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$$\Psi_s = \Psi_p$$
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$$\Psi_s = 0$$
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$$\Psi_w = \Psi_s + (-\Psi_p)$$
Explanation
The measure of the relative tendency of water to move from one area to another is water potential.
The expression in A is true for the plasmolyzed cell, which means osmotic potential equals water potential in the plasmolyzed cell. In the plasmolyzed cell, plant cell loses water, pressure potential lowers and water potential then becomes equal to osmotic potential.
So, the correct option is
$$\Psi_w = \Psi_s$$
Different substances move independently depending on their own concentration gradients in?
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Simple diffusion
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Bulk flow
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Osmosis
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All the above
Explanation
Diffusion is a passive movement of molecules along their concentration gradient. While osmosis is the diffusion of water molecules through a differentially permeable membrane or semipermeable membrane.
So the correct option is "Simple diffusion".
Pickles, jams, jellies have low risk of spoilage as they cause.
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Guttation
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Diffusion
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Plasmolysis
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Imbibition
Explanation
In the process of making pickles, jams and jellies addition of more concentration of salt and sugar takes place. Because of the hypertonic nature of these items, the food spoiling organisms such as yeast, moulds cannot grow on them. When a cell placed in hypertonic solution, it undergoes plasmolysis. In the same manner, due to the high concentration of salt and sugar, they preserve for a long time.
Hence, the correct answer is option C.
The process of facilitated diffusion is different from active transport due to
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Involvement of membrane protein
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Its response to protein inhibitors
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Being a downhill process
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Saturation of transport
Which of the following is wrongly matched?
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Hypotonic solution - Plasmolysis
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Transpiration pull - Ascent of sap
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Root pressure - Guttation
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Pressure flow - Phloem transport
Explanation
Plasmolysis occurs when water moves out of the cell and the cell membrane of a plant cell shrinks away from its cell wall. This occurs when a cell is placed in a hypertonic solution.
Transpiration is a process, in which the excess water is evaporated through stomata. The ascent of sap takes place by transpiration pull in plants. Roots actively transport ions through water and increase the pressure inside xylem, this pressure pushing up water to small heights.
Excess water collects in the form of droplets by root pressure such as water loss in the liquid phase is called guttation.
Phloem tissue is composed of sieve tube cells. As hydrostatic pressure in the phloem sieve tube increases, pressure flow begins, and sap moves through the phloem.
Hence, the correct answer is option A.
Root pressure is generally not found in
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Wheat plant
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Colocasia
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Pinus
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All of these
Water movement against gravity is caused by?
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Imbibition
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Transpiration
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Osmosis
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Diffusion
Explanation
Water movement against gravity is caused by transpiration. Transpiration is the process by which water is carried through plant roots to small pores of the leaves, where it changes to vapor and is released to the atmosphere. The mechanism of transport of water against gravity is by cohesive forces of water molecules. Water molecules cohere and are pulled up the plant by the tension, exerted by evaporation at the leaf surface.
Thus, the correct answer is option B.
According to mass flow hypothesis
(a) Sucrose is moved into the companion cells and then into the sieve tube by passive transport.
(b) Inside the phloem, an osmotic pressure gradient is generated that facilitates the mass movement in the phloem.
(c) Water in the adjacent xylem moves into the phloem by active process
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(a) and (c) are correct
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(b) and (c) are incorrect
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(a) and (c) are incorrect
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(a) and (b) are correct
If a plant cell is placed in deionised water, the water potential of that cell becomes ___________________________.
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More positive because pressure potential becomes more positive
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More positive because pressure potential becomes more negative
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More negative because pressure potential becomes more negative
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Less negative because pressure potential becomes more positive
Explanation
If a plant cell is placed in deionised water will enter the cell and the cell will burst, the water potential also becomes negative.
So, the correct option is 'More negative because pressure potential becomes more negative'
The most important forces for the ascent of sap in plants are?
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Imbibition and capillary
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Suction pressure and cohesion
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Capillary and root pressure
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Root pressure and pulsation
Explanation
The process by which water and minerals translocate from base to apex of the plant is known as the ascent of sap. It takes place through complex tissue xylem. Most important forces for the ascent of sap are; root pressure and capillary action.
Active transport of water takes place through xylem by a pressure called root pressure. It is responsible for pushing up water to small heights in the stem.
The tubes in the plant stem are very tiny and the movement of water through tiny tubes is called capillary action. This occurs when the adhesion is stronger than the cohesion. Water molecules are naturally attracted to each other.
Hence, the correct answer is option C.
The direction of the water flow in given cells X, Y & Z can be presented as?
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X $$\rightarrow$$ Y $$\leftarrow$$ Z
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X $$\rightarrow$$ Y $$\rightarrow$$ Z
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X $$\leftarrow$$ Y $$\leftarrow$$ Z
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X $$\leftarrow$$ Y $$\rightarrow$$ Z
Plasmolysis occurs due to :
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Exosmosis
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Endosmosis
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Presence of solutes
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Semipermeability of cell membrane
Bulk flow or mass flow.
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Can be achieved through root pressure
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Can be achieved through transpiration pull
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Can be achieved either through a positive Hydrostatic pressure or a negative hydrostatic pressure
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More than one option is correct
If some sugar is dissolved in pure water, its water potential.
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Remain same
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Decreases
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Increases
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First increases than decreases
Pressure potential is usually positive but negative in case of?
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Xylem vessels
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Plasmolysed cell
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Both A and B
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Turgid cell
Explanation
Pressure potential is usually positive but negative in the case of xylem vessels. It
was known formerly as wall pressure or turgor pressure. In a turgid plant cell,
pressure potential is usually positive but, negative in case of xylem, the
potential pressure of xylem in a transpiring plant, which is under considerable
tension, will be negative.
The function of C and D
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Motor and Sterile air outle
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Agitation and Aeration
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Foam detector and Agitation
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pH detector and Temperature detector
Root pressure is due to?
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Diffusion
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Passive transport
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Active transport
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Osmosis
A and B are contiguous cells. A has OP $$=10$$ atm, TP $$=7$$ atm and DPD$$=3$$atm. B has OP$$=8$$ atm, TP$$=3$$ atm, DPD $$=5$$ atm, The result would be?
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No movement of water
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Equilibrium between the two
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Movement of water from A to B
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Movement of water from B to A
Facilitated diffusion cannot cause net transport of molecules from a low to a high concentration because?
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This would require output of energy.
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This would require input of energy.
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This would not require nor release energy.
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This would not be permitted by the membrane.
The pressure exerted by the protoplasts due to entry of water against rigid walls is called
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Solute potential
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Pressure potential
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Osmotic pressure
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Turgor pressure
Root pressure influence.
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Evaporation
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Transpiration
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Guttation
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Both (B) and (C)
Guttation is caused due to?
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Transpiration
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High root pressure
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Closure of stomata
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Bleeding
Mark out the incorrect statements.
i) Bulk flow can be achieved through a positive hydrostatic pressure.
ii) Bulk flow can achieved through a negative hydrostatic pressure.
iii) Plasmolysis usually occurs in nature
iv) Imbibition also involves diffusion of water.
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i & iii
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Only iii
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iii & iv
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ii & iv
Explanation
Plasmolysis doesn't occur in nature. It is the separation of plant cell cytoplasm from the cell wall due to the loss of water. It is mostly a laboratory-induced process and doesn't occur naturally.
Imbibition is one of the types of diffusion of water in which water is absorbed by colloidal solids.
Bulk flow is achieved through both positive and negative hydrostatic pressure.
So the correct option is C.
Choose an appropriate term for loss of water in the form of droplets through grass blade.
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Exosmosis
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Transpiration
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Guttation
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Respiration
Water moves from a cell with ________ water potential to a cell with ________ water potential.
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Higher, Lower
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Lower, Higher
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Less negative, More negative
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Both (i) and (iii)
Explanation
Water potential moves higher to lower and affected by both solute and pressure potential in the cell and outside the cell.
Swelling up of raisins when kept in water is due to
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Osmosis
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Exo-osmosis
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Imbibition
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Plasmolysis
Movement of water through the symplast involves crossing the
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Intercellular spaces
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Cell wall
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Cell membrane
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More than one option is correct
Which of the following statements about the mass flow hypothesis is wrong?
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It is the accepted mechanism for translocation of sugars from source to sink
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As glucose is prepared at source it is converted to source
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Sucrose is actively loaded into a sieve tube
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The process of loading at source produces a hypotonic condition in the phloem
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Water in the adjacent xylem moves into the phloem by osmosis.
Which of the following is correct about symplast?
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Living continuum
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Cell wall and intercellular space
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Non-Living continuum
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None of these
Explanation
The symplastic system is the system of interconnected protoplasts neighboring cells are connected through cytoplasmic strands that extend through plasmodesmata. Symplast cells have more than one nucleus
During the symplastic moment, water travels through the plasmodesmata.
As the symplastic system is the system of interconnected protoplast it is considered as a living continuum.
Hence Living continuum is correct about symplast.
So, the correct answer is 'Living continuum'.
Facilitated diffusion require _________ to transport substance across membrane.
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Special membrane protein
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ATP
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Protein inhibitor
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All
Which one of the following anatomical structures is involved in guttation ?
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Cuticle
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Hydathodes
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Lenticels
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Stomata
Dry seeds when placed in water swells due to?
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Imbibition
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Absorption
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Diffusion
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Adsorption
Explanation
Imbibition is the first phenomenon in seed germination. Imbibition is a passive physical process and is actually adsorption of water by the dry surface. It causes swelling of dry seeds.
Transpiration is defined as:
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The rise of water up to the stem of a plant.
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The elimination of water with dissolved water products.
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The loss of water as water vapour from the aerial parts of a plant.
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The loss of water as water vapour from the roots as well as the leaves of the plant.
Explanation
Transpiration is the loss of water vapour from the aerial part (leaves) of a plant.
Thus, the correct answer is (C).
Raisins swell when put in:
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Rainwater
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Tap water
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Mustard oil
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Saturated sugar solution
Explanation
Raisins swell because of the process of osmosis (Solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one).
When raisins put into water (solvent) with less amount of salt (e.g. Rainwater).
Thus, the correct answer Rainwater from the given above options.
Porins are:
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Pores in membrane
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Channel in membrane
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Proteins that act as a channel
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None of the above
Explanation
Correct Option: C
Explanation:
Porins are beta barrel proteins that cross a cellular membrane and act as a pore, through which molecules can diffuse
. Unlike other membrane transport proteins, porins are large enough to allow passive diffusion, i.e., they act as channels that are specific to different types of molecules.
The porins are a class of transmembrane proteins whose structure differs radically from that of other integral proteins.
At atmospheric pressure a solution has $$\psi\,s = -5$$, what will the water potential be for this solution?
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$$-5$$
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$$5$$
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$$0$$
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Cannot be calculated.
Explanation
Water potential $$\psi$$ = $$\psi_s$$ + $$\psi_p$$, at atmospheric pressure water potential is equal to solute potential, that is,
$$\psi$$ =
$$\psi_s$$
Which is equal to -5.
So, the correct answer is '
−
5'
An ideal molar solution at $$0^{0}C$$ will have an osmotic pressure of
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10 atmosphere
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20 atmosphere
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22.4 atmosphere
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4.3 atmosphere
Explanation
Osmotic pressure refers to the minimum pressure that needs to be applied to a solution to prevent the inward flow of water in a semipermeable membrane. Jacobus Van't Hoff proposed the law which relates the osmotic pressure to solute concentration which states that
osmotic pressure is simply proportional to the solute concentration and when the solute concentration is sufficiently low that the solution is considered as the ideal solution. According to the Van't Hoff equation, an ideal solution that contains 1 mole of dissolved particles per litre of solvent at 0° C will have an osmotic pressure of 22.4 atm.
If a potted plant is covered with a glass jar, water vapours appear on the wall of the glass jar. This phenomenon occurs .............
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Due to transpiration
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Due to respiration
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Due to reproduction
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Due to photosynthesis
Explanation
It occurs due to transpiration. Transpiration is the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere. Transpiration is essentially evaporation of water from plant leaves.
Therefore, the correct answer is option A.
Dry wooden stakes, if driven into a small crack in a rock and then soaked, can develop enough pressure to split the rock. Such pressure is build up through the phenomenon of
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Imbibition
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Deplasmolysis
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Turgor pressure
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Osmotic pressure
Explanation
Imbibition is a physical process in which a dry surface absorbs water. In rocks, the dead material absorbs water resulting in an increase in volume, which splits the rock. This process is the primary force responsible for the cracking of rocks in nature and leads to weathering of rocks. Weathering of rocks is an important step in soil formation.
So, the correct answer is option A.
If a cell has equal water concentration to its surrounding medium, .......... will be observed.
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No effect
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Endosmosis
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Passage of water inward and outward
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Cell will burst out
Explanation
When a cell is kept in hypotonic solution that has a lower concentration of solutes than the cell does, the solution will move from outside to inside. This is known as endosmosis. Cell may burst due to excess water inside the cell during endosmosis. During diffusion, there is free inward and outward passage of water across the cell. When cell is kept in isotonic solution that has equal water concentration as that of cell, there is no net movement of water.
Thus, the correct answer is option A.
The osmotic potential and pressure potential of three cells (A,B,C) located in different parts of an actively transpiring plant are given below.
Cell
Osmotic potential
(mpa)
Pressure potential
(mpa)
A
-0.87
0.44
B
-0.92
0.34
C
-0.68
0.27
Identify these three cells as root hair, root cortical and leaf mesophyll cells respectively.
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A, B, C
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A, C, B
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C, A, B
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B, C, A
Explanation
Water potential is calculated by the sum of osmotic potential and pressure potential. Further water moves from higher water potential to lower water potential. The calculated values of water potential for three cells A, B and C are -0.43, -0.58 and -0.41. Thus water will flow from C to A to B. This indicates that cell C must be root hair, A must be root cortex and B must be leaf mesophyll.
So, the correct answer is '
C, A, B'
The ratio of osmotic pressure exerted by 1 M sucrose and 1 M $$NaCl$$ solution will be
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1
0%
2
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0.1
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0.5
Explanation
The osmotic pressure depends on the concentration of solute molecules in the solution.
A molecule of sodium chloride will break up into two ions of sodium and chloride after dissolving in water.
While a molecule of sucrose will not break up into separate ions.
Since the no. of solutes will be double in the case of $$NaCl$$ solution then the solution of sucrose, the ratio of osmotic pressure exerted by the solution of an equal concentration of sucrose and sodium chloride will be 1:2, i.e. - 0.5.
So, the correct answer is 'option D'.
When osmotic potential is either zero or negative and pressure potential is positive, then the water potential will be
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Negative
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Positive
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Sometimes negative sometimes positive
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None of the above
Explanation
Water potential of a solution is always negative because by convention water potential of pure water is assumed to be zero. When solutes are dissolved in water, then water potential decreases. But for a cell the formula to calculate water potential is that water potential is algebraic sum of osmotic potential (which may be zero or negative) and pressure potential which is always positive. Hence, depending on the relative magnitudes of osmotic potential and pressure potential; the value of water potential can be negative or positive.
A cell will swell up if
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The concentration of water molecules in the cell is higher than the concentration of water molecules in surrounding medium.
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The concentration of water molecules in surrounding medium is higher than water molecules concentration in the cell.
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The concentration of water molecules is same in the cell and in the surrounding medium.
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Concentration of water molecules does not matter.
Explanation
Correct option: B
Explanation:
Endosmois
is the process by which water from the surroundings gets into the cells as the water content outside the cell is higher.
As a result, the
cell swells
up.
Exosmois
is the process in which water molecules move out from the cell as its content is higher inside the cell.
As a result, the
cell shrinks.
And if the water content on either side remains the same there is
no change in the shape of the cell.
The concentration of water molecules determines the
movement of wate
r.
Hence, a
cell will swell up if "
t
he concentration of water molecules in surrounding medium is higher than water molecules concentration in the cell".
Which of the following seeds will show more imbibition pressure?
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Sesame seeds
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Gram seeds
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Wheat seeds
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Rice seeds
Explanation
Gram seeds are rich in proteins. Proteins imbibe more water as compared to starch or fats. Hence, seeds rich in proteins like gram and chickpea will imbibe more water. Hence, if we soak dry seeds of gram or chickpea in water, they will show more increase in volume as compared to seeds storing starch like wheat and rice or fats like s
esame seeds
.
0.1M solution of a solute has a water potential of
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-2.3bars
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0 bar
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22.4 bars
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+ 2.3 bars
Explanation
Assuming pressure potential to be zero i.e. the cell was flaccid initially, the water potential will be equal to the osmotic potential created by addition of solute to a final concentration of 0.1 M.
The osmotic potential created due to 0.1 M solute will be = M R T. Where R is universal gas constant, whose value is 0.083145 bar per kelvin per litre and T is absolute temperature in Kelvin. Substituting the values in this formula we get -0.1*0.083145*298 = $$-2.3 bars$$.
So, the correct answer is option A.
If cell A with $$OP=5$$ and $$TP=4$$ is surrounded by cells with OP and $$TP=1$$, what will be the action of water movement?
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Water will not move up
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From other cells to cell A
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From cell A to other cells
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None of the above
What happens if dry apricots are left for some time in the pure water and later transferred to sugar solution?
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First it swells due to endosmosis and then exosmosis occurs and it shrinks.
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First it shrinks due to endosmosis and then exosmosis occurs and it swells.
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No change.
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Apricot will be burst out.
Explanation
Dry apricots have more solutes than pure water. Hence, endosmosis, i.e., water molecules will move from outside to inside of the apricot through wall of apricot takes place. Due to this, apricots will swell eventually.
When such apricots are then transferred to sugar solution, then the solution will be hypertonic bearing high amount of solute. Hence, exosmosis, i.e., water will move from inside to outside of apricot through apricot wall. Due to this, apricot will shrink.
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