NCERT Solutions for Class 7 Science Chapter 1: Nutrition in Plants

1. Nutrition in Plants Plants are rockstars when it comes to making their own food! Unlike us, they don’t need to rely on others for meals. In chapter Nutrition in Plants dives into how plants are self-sufficient through a process called photosynthesis. Here’s the breakdown: ● Plants are called autotrophs because they can make their own food (auto = self; trophos = nourishment). ● The amazing process of photosynthesis is their secret weapon. In this process, plants use sunlight, water, and carbon dioxide to cook up their food (usually glucose, a type of sugar). ● Sunlight acts like the stove, chlorophyll (a green pigment found in leaves) is the chef, and water and carbon dioxide are the ingredients. ● This yummy plant food is then stored as starch for later use. ● An important bonus of photosynthesis is the release of oxygen, which we all need to breathe! ● Besides making their own food, plants also absorb nutrients like nitrogen, phosphorus, and potassium from the soil for healthy growth. Remember, plants are the base of the food chain. They provide food not only for themselves but also for animals (directly or indirectly), making them super important for life on Earth. NCERT Solutions for Class 7 Science Chapter 1: Nutrition in Plants Q1. Why do organisms need to take food? Ans. Organisms need food for three main reasons: 1.Energy: Food provides the fuel for all our (and their) activities. Whether it’s running, growing, or even thinking, our bodies (and theirs) break down food to get energy to keep going. 2.Growth and Repair: Just like building a house, our bodies (and theirs) need materials for building and fixing themselves. Food

2. provides the essential building blocks, like proteins, to grow when we’re young and repair injuries throughout our lives. 3.Overall Functioning: Food is packed with more than just fuel and building materials. It also contains vitamins, minerals, and other nutrients that keep our bodies (and theirs) functioning properly. These help fight disease, build strong bones, and regulate many important processes. Q2. Distinguish between a parasite and a saprotroph. Ans. Here is a table distinguishing between a parasite and a saprotroph: Parasite Saprotroph Lives on or inside another organism (host) and harms the host Feeds on dead and decaying organic matter Steals nutrients directly from the host Absorbs nutrients from decomposed matter Harms the host No effect on the host None Recycles nutrients Q3. How would you test the presence of starch in leaves? Ans. You can test for starch in leaves using iodine. Boil a leaf briefly, then soak it in alcohol to remove chlorophyll (making it translucent). Add iodine – if it turns blue-black, starch is present! Brown means little to no starch. Q4. Give a brief description of the process of synthesis of food in green plants. Ans. Green plants are like tiny food factories! Here’s a quick rundown of how they make their own food through photosynthesis:

3. 1.Ingredients: Plants gather sunlight (energy source), water from the soil, and carbon dioxide from the air. 2.The Chef: Chlorophyll, a green pigment in leaves, acts like the chef. 3.The Recipe: Sunlight energy is captured by chlorophyll, which uses it to split water and combine the resulting hydrogen with carbon dioxide. 4.The Dish: This amazing process creates glucose (a type of sugar), the plant’s food. 5.The Leftovers: Oxygen, a gas we need to breathe, is released as a byproduct. Q5. Show with the help of a sketch that the plants are the ultimate source of food. Ans. Sun | Light | +———+ +———+ +———-+ | Plant | —- | Herbivore | —- | Carnivore | +———+ +———+ +———-+ | | ^ Eat Eat Eat (meat from herbivore) Decomposers (not shown) break down dead plants and animals, returning nutrients to the soil. Q.6. Fill in the blanks:

4. (a) Green plants are called ________________ since they synthesise their own food. (b) The food synthesised by the plants is stored as ________________ . (c) In photosynthesis solar energy is captured by the pigment called ________________ (d) During photosynthesis plants take in ________________ and release ________________ . Ans. (a) autotrophs (b) starch (c) chlorophyll (d) carbon dioxide, oxygen Q.7. Name the following: (i) A parasitic plant with yellow, slender and tubular stem. (ii) A plant that has both autotrophic and heterotrophic mode of nutrition. (iii) The pores through which leaves exchange gases. Ans. (i) cuscuta (ii) Insectivorous plant (iii) Stomata Q.8. Tick the correct answer: (a) Amarbel is an example of: (i) Autotroph (ii) Parasite (iii) Saprotroph (iv) Host (b) The plant which traps and feeds on insects is: (a) Cuscuta (ii) China rose {iii) Pitcher plant (iu) Rose Ans. (a) (ii) Parasite (b) (iii) Pitcher plant Q.9. Match the items given in Column I with those in Column II:

5. Column I Column II Chlorophyll Bacteria Nitrogen Heterotrophs Amarbel Pitcher plant Animals Leaf Insects Parasite Ans. Column I Column II Chlorophyll Leaf Nitrogen Bacteria Amarbel Parasite Animals Heterotrophs Insects Pitcher plant Q.10. Mark T’ if the statement is true and ‘F’ if it is false: (i) Carbon dioxide is released during photosynthesis. (T/F) (ii) Plants which synthesise their food themselves are called saprotrophs. (T/F) (iii) The product of photosynthesis is not a protein. (T/F) (iv) Solar energy is converted into chemical energy during photosynthesis. (T/F) Ans. (a) F (ii) F (iii) T (iu) T Q.11.Choose the correct option from the following. Which part of the plant takes in carbon dioxide from the air for

6. photosynthesis? (i) Root hair (ii) Stomata (iii) Leaf veins (iv) Sepals Ans. (ii) Stomata Q.12. Choose the correct option from the following: Plants take carbon dioxide from the atmosphere mainly through their: (i) Roots (ii) Stem (iii) Flowers (iv) Leaves Ans. (iv) Leaves