Hello Readers, Welcome to the first blog post in Class 7 Science. In this category, I will provide NCERT and JKBOSE Solutions for Class 7 Science. In today’s post, I am detailing Nutrition in Plants Class 7th Question Answers. Let us get started with today’s post by having a brief overview of what you have studied in this chapter as you must have your basics clear before moving on to solutions of the chapter. The following topics are discussed in this chapter:
Nutrition in Plants Class 7th Question Answers
Overview of Chapter
- MODES OF NUTRITION.
- PHOTOSYNTHESIS-FOOD MAKING PROCESS IN PLANTS.
- SYNTHESIS OF FOOD OTHER THAN CARBOHYDRATES IN PLANTS.
- OTHER MODES OF NUTRITION IN PLANTS.
- HOW NUTRIENTS ARE REPLENISHED IN THE SOIL.
NUTRITION: The process of taking food by an organism and its utilisation by the body is called nutrition. It is the fundamental life process because all other processes stem from it. Energy gained through nutrition is used to maintain other life processes.
MODES OF NUTRITION: The methods of obtaining food are called modes of nutrition. There are two major types of nutrition.
- Autotrophic Nutrition: The mode of nutrition in which living organisms make their own food from raw materials by the process of photosynthesis is called autotrophic nutrition. The organisms which show this type of nutrition are called autotrophs (Green Plants).
- Heterotrophic Nutrition: The mode of nutrition in which cannot prepare their own food and are dependent on other plants and animals for their food is called heterotrophic nutrition.
The organisms which show this type of nutrition are called heterotrophs.
PHOTOSYNTHESIS-FOOD MAKING PROCESS IN PLANTS: The process by which green plants prepare their own food from simple inorganic substances (carbon dioxide and water) in presence of sunlight and chlorophyll is called photosynthesis.
- Site for Photosynthesis: The process of photosynthesis takes place in the leaves of green plants and for this reason, leaves are also called the food factories of plants. The plants in which leaves are reduced photosynthesis takes place in the stem.
- Conditions Necessary for Photosynthesis: The presence of carbon dioxide, water, chlorophyll, and the sunlight is necessary for the process of photosynthesis to take place.
- Importance of Photosynthesis: The process of photosynthesis is the source of all the food on the earth. It is also necessary for the production of oxygen gas in the atmosphere which is necessary for the respiration of organisms.
SYNTHESIS OF FOOD OTHER THAN CARBOHYDRATES IN PLANTS: There are some other forms of food which are present in plants.
- Oils or Fats as Food: – There are certain plants which convert carbohydrates into oils and fats and store them in seeds.
- Proteins as Food: – Plants also have proteins in them which are made by the combination of carbohydrates and nitrogen compounds (nitrates).
- Vitamins as Food: – These are highly complex substances prepared by plants and needed by us.
OTHER MODES OF NUTRITION IN PLANTS: There are some plants which do not have chlorophyll and so they cannot synthesize their own food. So, they like other animals depend on other living organisms for their food. They perform a heterotrophic mode of nutrition. Here are some other modes of nutrition in plants.
- a) Parasitic Plants
- b) Insectivorous Plants.
SAPROTROPHS: The mode of nutrition in which organisms take their nutrients from dead and decaying matter is called saprotrophic nutrition and the organisms which perform saprotrophic nutrition are called saprotrophs.
Symbiotic Plants: Symbiosis is the mode of living in which two organisms of different species live together and benefit each other in obtaining food. The two different species of plants live together as part of the same plant and benefit each other in finding food. For example. Lichens are an association of fungi and algae.
HOW NUTRIENTS ARE REPLENISHED IN THE SOIL: The replenishment of nutrients in the soil can be done in the following ways: –
- Adding fertilizers and manures to the soil. Example. Urea, NPK,
- By growing leguminous plants like pulses peas, gram moong etc.
Nutrition in Plants Class 7 Questions
- Why do organisms need to take food?
Ans. Organisms need to take food for the following purposes.
- a) Food helps the organism to grow.
- a) It gives them the energy to carry out various life processes.
- c) It helps living organisms build and repair the damaged parts of their bodies.
- d) Food also helps organisms to fight against diseases.
- Distinguish between parasite and saprotroph.
|1. These are the organisms which live on or inside the body of other organisms and obtain food from them.
|1. These are the organisms which obtain their food from dead decaying matter.
|2. These organisms have some special organs like suckers and hooks to remain attached to the host and obtain food from them
|2. These organisms secrete digestive enzymes to organic matter convert into solution and absorb it by their body surface.
|3. They are harmful to the body of the host organism.
Example. Cuscuta, Tape-worm, Round-worm
|3. They act as cleaning agents as they remove the dead decaying matter present on the earth. Example. Fungi, Bacteria.
- How do you test the presence of starch in the leaves?
Ans. The presence of starch or carbohydrate in the leaves of the plant can be tested by performing an iodine test. To perform the iodine test we take green leaves and boil them in alcohol to remove chlorophyll and then put 2-3 drops of iodine solution on the boiled leaves. We find that the iodine solution turns blue-black which indicates the presence of starch in the leaves.
- Give a brief description of the process of synthesis of food in green plants.
Ans. Photosynthesis is the process by which green plants prepare their food using carbon dioxide and water in the presence of sunlight and chlorophyll. In this process, chlorophyll captures solar energy from the sun and converts it into chemical energy and stores it as food in plants. The process of photosynthesis is represented by the following reaction.
- Show with the help of a sketch that plants are the ultimate source of food.
Ans. The following sketch shows that plants are the ultimate source of food.
- Fill in the blanks.
- a) Green plants are called autotrophs since they synthesise their own food.
- b) The food synthesized by plants is stored as starch.
- c) In photosynthesis solar energy is captured by the pigment called chlorophyll.
- d) During photosynthesis plants take in carbon dioxide and release oxygen.
- Name the following:
- i) A parasitic plant with a yellow, slender and tubular stem.
- ii) A plant has both autotrophic and heterotrophic modes of nutrition.
Ans. Pitcher Plant.
iii) The pore through which leaves exchange gases.
- Tick the correct answer:
a) Amarbel is an example of:
Ans. (ii) Parasite.
b) The plant which traps and feeds on insects is:
(ii) China rose
(iii) Pitcher plant
Ans. (iii) Pitcher Plant.
- Match the items given in Column I with those in Column II:
- Mark ‘T’ if the statement is true and ‘F’ if it is false:
- Carbon dioxide is released during photosynthesis. (False)
- Plants which synthesise their food themselves are called saprotrophs. (False)
- The product of photosynthesis is not a protein. (True)
- Solar energy is converted into chemical energy during photosynthesis. (True)
- Choose the correct option from the following:
Which part of the plant gets carbon dioxide from the air for photosynthesis?
(i) Root hair
(iii) Leaf veins
Ans. (ii) Stomata.
- Choose the correct option from the following:
Plants take carbon dioxide from the atmosphere mainly through their:
Ans. (iv) Leaves.
- Tick mark (√) the correct choice:
(i) Which one of the following is an insectivorous plant?
(b) Venus fly trap
Ans. (b) Venus fly trap
(ii) Two different organisms living together and both benefitting each other are known as:
Ans. (b) Symbiotic.
(iii) Tiny pores on the surface of leaves are:
(d) Leaf Scale
Ans. (b) Stomata.
(iv) Which of the following is the green colour pigment in leaves:
That’s all about Nutrition in Plants Class 7th Question Answers. Hope it has helped. Do share your views about this post in the comment section below.