Nutrition In Plants - Class 7 Biology - Extra Questions

Green plants are known as ___________.

Green plants are known as autotrophs. Because green plant can make their own food with the help of sunlight, water, carbon dioxide and chlorophyll.


What is 'Autotrophic nutrition?' Give one example:

  • There are two processes by which organisms obtain nutrition. In autotrophic nutrition, the organism prepares its food from simple substances present in the surroundings. In heterotrophic nutrition, organism obtains food from digesting organic compounds. Autotrophs are the producers in the food chain. 
  • There are two types of autotrophs: photoautotrophs and chemoautotrophs. Photoautotrophs get their energy from sunlight and convert it into usable energy (sugar). This process is called photosynthesis. 
  • Chemoautotrophs are organisms that obtain energy from inorganic chemical processes.
  • For example, venus flytrap is also called Dionaea muscipula, these plants often trap insects by eating them. If an insect lands on a venus flytrap, it would activate the “trap” by touching the plant’s “hairs” and would be crushed by the plant. After doing so, a venus flytrap receives nutrients from the insect. These plants are still autotrophic because they mainly receive food from sunlight.


Define photosynthesis.

The process, by which the plants convert $$CO_{2}$$ absorbed from the atmosphere and $$H_{2}O$$ absorbed from the soil into carbohydrate in the presence of sunlight, is called photosynthesis.
In other words synthesis of carbohydrate by green plants from $$CO_{2}$$ and $$H_{2}O$$ in the presence of sunlight is called photosynthesis.


What will happen if nitrogen fixation does not take place?

$$\textbf{Solution:}$$

$$\bullet$$Organisms will be unable to grow in the absence of nitrogen fixation.
$$\bullet$$Plants that are deficient in nitrogen appear pale or yellowish. 
$$\bullet$$They produce fewer flowers and fruits than other plants.
$$\bullet$$The majority of plants will not be able to directly consume nitrogen from the environment.
$$\bullet$$Fixation converts free nitrogen to nitrate and ammonia, which are then transformed into amino acids, proteins, and other important nitrogenous molecules. 
$$\bullet$$Such chemicals that are necessary for functional and structural growth will not be generated if nitrogen fixation does not occur.



The .......... capture the energy present in sunlight and convert it into chemical energy.

The autotrophs capture the energy present in sunlight and convert it into chemical energy. 
Green plants are the autotrophs and primary producers as they are capable of capturing sunlight. They do so by the process of photosynthesis. In this process, the plants trap solar energy with the help of a pigment chlorophyll. This energy is then used to convert the raw materials, namely, carbon dioxide and water to produce glucose and oxygen. This glucose stores solar energy in the form of chemical energy. 




What happens to the cell if the nucleus is removed? Give reasons to support your answer?

The nucleus is the main controller of a eukaryotic cell. Its main function is to store the genetic material in the form of DNA. It undergoes transcription to make RNA that undergoes translation to form proteins. The proteins are used in various cellular functions such as making hormones and enzymes. Hence in the absence of a nucleus, the cell will die.


The cytoplasm and nucleus are enclosed within the 

The cytoplasm and nucleus are enclosed within the cell membrane, also called the plasma membrane.


Plants are autotrophic. Can you think of some plants that are partially heterotrophic?

$$\textbf{Solution:}$$

$$\bullet$$ Plants are autotrophic in nature which means they can produce their own food. 

$$\bullet$$ Plants perform photosynthesis which produces carbohydrates as the nutrient which is used by the plant. 

$$\bullet$$ Using carbon dioxide and water in the presence of sunlight photosynthesis is performed by the plants. 


$$\textbf{Plants are partially heterotrophic:}$$

$$\bullet$$ Some of the plants are there are partially heterotrophic.

$$\bullet$$ This means they depend on other organic sources for food without photosynthesizing on their own. 


$$\textbf{Insectivorous plants:}$$

$$\bullet$$ Insectivorous plants draw nutrition from insects. These plants live in nitrogen-deficient soil, and they have specially modified structures that entrap the insects.

$$\bullet$$ The insectivorous plants get the required nitrogen from the insects. 

$$\bullet$$ Thus the requirement of organic nutrients depends on insects as a source, making the plant partially heterotrophic. 

$$\bullet$$ Examples: Venus flytrap, Sundew. 


$$\textbf{Parasitic plants:}$$

$$\bullet$$ Parasitic plants depend on other plants for their nutrition. The parasitic plants get all the nutrition from the host plant.

$$\bullet$$ The host plant produces the nutrients for photosynthesis. 

$$\bullet$$ This makes the parasitic plants heterotrophic in character. 



Distinguish between : Autotrophic nutrition and heterotrophic nutrition.

 Autotrphic nutrition Heterotrophic nutrition
Food is synthesised from the inorganic raw materials such as CO$$_{2}$$, water and sunlight. Food is obtained directly from autotrophs.
Chlorophyll is necessary for this process. Chlorophyll is not necessary for this process.
 Food is prepared in the presence of sunlight, i.e. during day time only.Food can be obtained any time.
 It is seen in some bacteria and all green plants. It is seen in all animals and fungi.


What are saprophytes? Give two examples.

$$\textbf{Solution}$$
$$\bullet$$ Saprophytes are the the microorganisms which are incapable of making their own food and they survive by feeding on dead and decaying matter. 
$$\bullet$$ During the process of feeding The saprophytes breakdown the compost organic matter into simpler forms. The process through which they derive the nutrition from the decaying organic matter is known as absorptive nutrition.
$$\bullet$$  Some of the common examples of saprophytes are bacteria fungi and many other microorganisms. Example:- mycorrhiza, mushrooms etc.




What is nutrition? Explain heterotrophic nutrition with their types.

$$\textbf{Solution:}$$ 


$$\textbf{Nutrition:}$$

$$\bullet$$ Nutrition is the process of intake of nutrients from which the organisms derive their energy. 

$$\bullet$$ In the process of nutrition, there are five major steps which are ingestion, digestion, absorption, assimilation and egestion. 

$$\bullet$$ Ingestion is the intake of nutrients by the mouth. 

$$\bullet$$ Digestion is the process of enzyme-mediated breaking down of the larger molecules into smaller forms. 

$$\bullet$$ Absorption is the process of absorbing the digested food materials and nutrients. 

$$\bullet$$ Assimilation is the process of movement of the nutrients to the cell where it is metabolized to produce energy. 

$$\bullet$$ Egestion is the process of removal of undigested food materials.


$$\textbf{Types of heterotrophic nutrition:}$$

$$\bullet$$ Heterotrophic nutrition is the mode of nutrition in which organisms get their nutrition with the digestion of organic matter from other organisms. 

$$\bullet$$ Heterotrophs are not able to synthesize their own food. 

$$\bullet$$ There are some processes of heterotrophic nutrition which are saprophytic nutrition, parasitic nutrition and holozoic nutrition. 


$$\textbf{Holozoic nutrition:}$$

$$\bullet$$ In this type of nutrition, the parts of plants or animals or a complete organism are taken in as food. 

$$\bullet$$ This is then digested to draw all the nutrients from the organism. After digestion, it is absorbed by the cells of the body. 

$$\bullet$$ Humans get their food using holozoic nutrition. 


$$\textbf{Parasitic nutrition:}$$

$$\bullet$$ Organisms that need to depend on the other living organism for nutrition are called parasites. 

$$\bullet$$ Parasites depend on their host organism from which they draw their nutrition directly. In this type of association, the host organism is affected and only the parasite is benefited. 


$$\textbf{Saprophytic nutrition:}$$

$$\bullet$$ The process of nutrition depends on dead and decaying organic matter. 

$$\bullet$$ From the dead organic matter, the nutrients are broken down with the help of specific enzymes. 

$$\bullet$$ Fungi is one of the common examples of saprophytes that grow on dead organic matter. 



What are the main functions of a nucleus?

The main functions of the nucleus include 
1. Transmission of hereditary characters 
2. Regulating all the activities of the cell by controlling the synthesis of protein 
3. Synthesis of ribosomes takes place in the nucleus due to nucleolus




What is Photosynthesis process? Write any two affective factors and explain their effects.

Photosynthesis is a process in which CO$$_2$$ is converted into carbohydrates in presence of light and chlorophyll by all organism processing chlorophyll.
Chemical equation for photosynthesis is as follows :
$$6CO_{ 2 }+12H_{ 2 }O\xrightarrow [ green\quad plants  ]{ sunlight} C_{ 6 }H_{ 12 }O_{ 6 }+6H_{ 2 }O+O_{ 2 }$$
Factors influencing the rate of photosynthesis are as  follows :
  1.  Light - with the increase in intensity photosynthesis increases.
  2. CO$$_2$$ - With increase in amount of CO$$_2$$ in atmosphere (0.03 to 0.04 %) it decreases.
  3. Water - Photosynthesis decreases with the decrease of water.
  4. Temperature - favourable temperature is 25-30$$^o C$$ . It shows adverse effect with increase or decrease of temperature
  5.  O$$_2$$ - Increase of CO$$_2$$ in the environment decreases the rate of photosynthesis.


Classify the organisms into different groups based on their mode of nutrition.

  • All living beings do not need the same kind of food. They have different food requirements. Depending on their food requirements, they are classified as:
1) Herbivores: Animals that eat only plant or plant products. Examples- cow, horse, rabbit, etc.
2) Carnivores: Animals that eat other animals. Examples- lion, tiger, etc.
3) Omnivores: Animals that eat both plants and animals. Examples- dog, cat, crow, etc.



What is nutrition? What type of nutrition is seen in green plants and the majority of animals?

  • Nutrition is the process of obtaining energy in the form of food, which is necessary for body growth and metabolism. Each and every organism obtain their nutrition by different ways.
  • Plants exhibit an autotrophic mode of nutrition. They prepare their own food. They are capable of fixing carbon dioxide using sunlight energy. They are the primary producers in the food chain.
  • The majority of animals are heterotrophs. They cannot prepare their own food. They depend on other organisms such as plants or other animals for their nutrition. They are consumers in the food chain.


The correct explanation of the organisms is

A
B
C
D
a)
Saprophyte
Heterotrophs
Autotrophs
Heterotrophs
b)
Heterotrophs
Autotrophs
Saprophyte
Saprophyte
c)
Autotrophs
Saprophyte
Autotrophs
Heterotrophs
d)
Autotrophs
Heterotrophs
Heterotrophs
Saprophyte

622964_89dae7de5fba48ad87136a9a1cdbe65a.png

 d)Autotrophs Heterotrophs Heterotrophs Saprophyte 


Distinguish between a parasite and a saprotroph

 $$\textbf{Parasite}$$ $$\textbf{Saprotroph}$$
Parasites are organisms that grow on the body of another organism for their food.Saprotrophs are organism that feed on dead and decaying organic matter for their nutrients.
They depend on hosts for readymade food.They depend on digested and decayed food.
They directly feed on living organisms for their nutrition.They feed dead and decayed organisms.
For example: Cactus and Orchids.For example: Fungus and some bacteria. 


Green plants are called ______ since they synthesize their own food.

Green plants are called autotrophs since they synthesize their own food.
Explanation: Green plants use solar energy to convert absorbed $$CO_2$$, water, and minerals like manganese and magnesium to prepare food. The food is the carbohydrate called glucose $$C_6H_{12}O_6$$ which is stored as starch. 


Fill in the blanks with appropriate words.

Nepenthes (pitcher plant) is an example of .......... plants.

Insectivorous


Fill in the blanks with appropriate words.

The jelly-like fluid which surrounds the nucleus and constitutes the true internal material of the cell is called _______.

The jelly-like fluid that surrounds the nucleus and constitutes the true internal material of the cell is called the cytoplasm. It contains all the cell organelles and ions necessary for survival.


What are 3 main parts of cell?

The cytoplasm, cell membrane and the nucleus are the 3 main parts of a cell. Cytoplasm is the part of the cell that contains the organelles and all the other components of the cell. The cell membrane or the plasma membrane acts as a barrier which only allows selective movement of substances into or out of the cell and the nucleus of the cell is the part that contains all the genetic information necessary for the cell to function.



Plants are called ________ because they fix carbon dioxide.

Plants are called autotrophs because they fix carbon dioxide. 
Autotrophic nutrition is a process in which the organism produces its food from simple inorganic materials such as water, carbon dioxide and mineral salts in the presence of sunlight.



Name the process by which autotrophs prepare their own food.

The process by which autotrophs prepare their own food from $$CO_2$$, $$H_2O$$ and sunlight is known as photosynthesis.



Define photoautotrophs.

Photoautotrophs are living organisms that can make their own food by using light and carbon dioxide through the process of photosynthesis. Green plants and photosynthetic microorganisms are examples of photoautotrophs. 


What is autotrophic nutrition ? Give one example of autotrophs. 

Autotrophic nutrition is the process of an organism being able to create/produce its own food.

Energy is needed to achieve this 

Two types of autotrophs are there:-

(1) Photosynthetic autotrophic

    $$\rightarrow$$ Uses sunlight as a source of energy

    Ex:- Higher plants, and cyanobacteria etc.

(2) Chemosynthetic Autotrops $$\rightarrow$$ Uses inorganic

molecules as a sources of energy Ex- archaebacteria.


What are the adaptations of leaf for photosynthesis ?

Leaves show following adaptations for photosynthesis:
(a) Flat surface to allow greater exposure to sunlight.
(b) Presence of chlorophyll to trap solar energy
(c) Larger number of stomata on lower surface to check transpiration but facilitate gaseous exchange.


Name the following.
Organisms that cannot prepare their own food.

Organisms that cannot prepare their own food are;
Heterotrophs 


Can you give me a name? Solve each of the following riddles by writing the name of the organism and its mode of nutrition. 
I live in water; people keep me in an aquarium and feed me. ______, _______. 

Fish lives under water in aquarium. They feed on other organisms as they are heterotrophs.
So, the correct answer is Fish, Heterotrophs.


Define autotrophic nutrition.

Autotrophic nutrition means that simple inorganic substances are taken in and used to synthesise organic molecules. Energy is needed to achieve this. There are two types of autotrophs: photoautotrophs and chemoautotrophs. Photoautotrophs get their energy from sunlight and convert it into usable energy (sugar). This process is called photosynthesis. During the process of photosynthesis, not only is sunlight turned into energy, but carbon dioxide is taken from the air and oxygen is released in its place. Chemoautotrophs use inorganic energy sources such as hydrogen sulfide, elemental sulfur, ferrous iron, molecular hydrogen, and ammonia.


Spot as many organisms as possible in the puzzle given as figure by encircling them as shown. Write the names on a sheet of paper and categorise them into autotrophs and heterotrophs. Classify the heteotrophs into herbivores, carnivores, omnivores and sapophytes.
1801914_978c2f2697f54cdb88d99770aede96bd.png

In the given puzzle number of organisms are 22. Some of them are shown in a below figure: 
Category of autotrophs and heterotrophs is given below:
Autotrophs: Mango, Rose, Carrot, Tulsi, Banyan, Bhindi, yam, Ginger.
Heterotrophs: Ant, Elephant, Tiger, Yeast, Fox, Mushroom, Mice, Crow, Owl, Cow, Fish, Rabbit, Bee. 

Classification of the heterotrophs into herbivores, carnivores, omnivores, and saprophytes are given below: 

Herbivores: Rabbit, Bee, Elephant, Cow.
Carnivores: Fox, Tiger.
Omnivores: Mice, Ant, Crow. Owl, Fish. 
Saprophytes: Yeast, Mushroom. 

1667809_1801914_ans_bef53ca9c2484a17af037bd8563223e4.png


What is the importance of stomata in the plant?

$$\textbf{Explanation:}$$

$$\bullet$$ Stomata are the small opening present on the lower surface of the leaf for the purpose of gas exchange and water transpiration.

$$\bullet$$ Exchange of gases in the leaves takes place with the help of stomata.

$$\bullet$$ If stomata are absent, plants can not take in carbon dioxide required for photosynthesis.


$$\textbf{Conclusion:}$$ Stomata performs gas exchange along with the transpiration.



Give reason- Animals are heterotrophic.​

Heterotrophs are the organism that are not able to synthesize their own food. Thus they are dependent on other organisms for food. Animals depend on plants or other animals for food. Hence they are heterotrophs. 


Differentiate between: autotrophs and heterotrophs.

 Autotrophs
 Heterotrophs
 Organisms that make their own food.Organisms that are dependent on other organisms for their food requirement. 
 They need sunlight. They don't need sunlight to get food.
 They need $$CO_2$$. They need $$O_2$$.


According to you, which organisms are greater in number – autotrophs or heterotrophs? Why?

Autotrophs that produce their own food, are greater in number than heterotrophs. It is because heterotrophs are dependant on autotrophs to meet their food requirements. If heterotrophs exceed the number of autotrophs, then all the autotrophs will vanish and so will be the heterotrophs. 


How do plants and animals get their energy in different ways?

Plants get their energy from starch whereas animals get it from glycogen.
1. Plants
They store energy in the form of starch in plastids called amyloplast.
Plants have two ways of storing energy:
1) As amylose (chained).
2) As amylopectin (branched just like glycogen in animals). 

2. Animals
Glycogen is a branched polysaccharide, made of monosaccharide glucose (sugar). It’s stored in our livers and muscles. When we need energy, this glycogen gets released into the bloodstream and breaks down into a monosaccharide- glucose that is used for instant energy.


Leaves are green because of me. Who am I?

I am chlorophyll.
Green colour of leaves is imparted by the pigment called chlorophyll. Chlorophyll helps in capturing energy from sunlight during photosynthesis.


Is the common edible mushroom an autotroph or a heterotroph? 

The common edible mushroom is a Heterotroph. 


Write the chemical reaction of photosynthesis and events occured during the process.

The chemical reaction for representing the chemical reaction of photosynthesis is
$$6CO_2 + 6H_2O \rightarrow  C_6H_{12}O_6 + 6O_2$$
                Sunlight energy
In photosynthesis reaction, energy is transferred from the light reaction step to dark reaction step by ATP. Photosynthesis is divided into two sets of reactions: the light-dependent (light) reactions and the light-independent (dark) reactions. As their names imply, the first set depends directly on light, whereas the second set does not. Nevertheless, even the dark reactions will cease if the plants are deprived of light for too long because they rely on the products of the light reactions. The light reactions, which convert the energy in light into chemical energy, take place within the thylakoid membranes of the chloroplasts, whereas the dark reactions, which use that chemical energy to fix $$CO_2$$ into organic molecules, take place in the stroma of the chloroplast. In the light reactions, the energy of light is used to split water, stripping a pair of electrons from it (and causing the two hydrogens to be lost), thus generating molecular oxygen. The energy in light is transferred to these electrons and is then used to generate adenosine triphosphate (ATP) and the electron carrier NADPH. These two products carry the energy and electrons generated in the light reactions to the stroma, where they are used by the dark reactions to synthesise sugars from $$CO_2$$.


What are the necessary conditions for autotrophic nutrition and what are its by-products?

Answer-
A) Necessary conditions required for autotrophic nutrition are:
1. Carbon dioxide
2. Water
3. Chlorophyll pigment 
4. Sunlight

B) Byproducts are:
1. Oxygen
2. Carbohydrates (glucose)

Autotrophic organisms are self-feeders that can synthesise their own food.
Green plants are photoautotrophs that can carry out photosynthesis.
Photosynthesis is a process in which atmospheric carbon dioxide is fixed and combined with water to form glucose and oxygen. 
Photosynthesis always takes place in the presence of sunlight which is captured by chlorophyll pigment present in plants.

The equation for photosynthesis is
$$6C{ O }_{ 2 }+6{ H }_{ 2 }O\longrightarrow { C }_{ 6 }{ H }_{ 12 }{ O }_{ 6 }+6{ O }_{ 2 }$$


Answer the following questions.
(a) By which process do green plants synthesize their food?
(b) Name the factors which take part in this process.
(c) Write the chemical equation of the above process.

(a) Photosynthesis is the process by which green plants can prepare their food in the form of carbohydrates. The light energy is captured by chlorophyll, the carbon dioxide is fixed and the food is prepared. 
(b) There are various factors that are responsible for photosynthesis. The common factors are carbon dioxide, chlorophyll, water, light and temperature.
(c) The reaction of photosynthesis is given 
Carbon dioxide + water + light energy → carbohydrate + oxygen.
The chemical equation is given as 
6CO2 + 6H2O -----------------------------> C6H12O6 + 6O2
                            Sunlight energy


Class 7 Biology Extra Questions