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This is a Class 7 CBSE Science Nutrition in Plants Worksheet. I have covered most of the topics. Take your time read the notes and practice all the questions in this test paper
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1. chloroplast Answer
2. absorb energy from the sunlight
3. a saprophyte
4. photosynthesis
5. starch
6. leaves
7. parasitic plant
8. autotrophic
9. heterotrophs
10. Carbon dioxide
11. phloem
12. fix nitrogen
13. stomata
14. swell
15.autotrophs
The leaves of the plant absorb carbon dioxide from the atmosphere through the stomata.Answer
Chloroplasts contain the green pigment called chlorophyll.Answer
Rhizobium live in the roots of leguminous plants such as gram, pea and beans.Answer
The food made by the leaves is in the form of sugar. It is transported to all the parts of the plant by a network of tubes called phloem tubes.Answer
After growing a crop such as wheat or rice, farmers usually grow a crop such as bean, pea or gram to maintain fertility of the soil. This practice is known as rotation of crops. These crops produce nitrogenous substances in their roots and make the soil fertile.Answer
Chlorophyll traps energy present in sunlight and uses it to make food for the plant. Some plants have leaves that do not appear green. These leaves also have chlorophyll. Chlorophyll in such leaves is masked by pigments of different colours.Answer
(a) Parasites- Cuscuta, RafflesiaAnswer
(b) Autotrophs- Mango tree, Neem tree
(c) Saprophytes- Mushroom, Yeast
(d) Insectivorous plants- Venus flytrap, Pitcher plant
(e) Symbiotic plants- Lichens, Mycorrhiza
(f) Leguminous plants- Peas, Beans
Leguminous crops do not need as much nitrogenous fertilizers as cereal crops. The roots of leguminous plants contain legumes or nodules within which reside bacteria called Rhizobium. These bacteria convert the atmospheric nitrogen into a soluble form that replenishes the soil and can be absorbed by roots.Answer
Answer
Lichens are a symbiotic form between algae and fungi. Algae have chlorophyll and produce food through photosynthesis while the fungi provide shelter to the algae and help it to survive in harsh weather conditions.Answer
The saprophytes such as fungi living in the soil feed on decaying plant and animal matter secrete digestive juices that break down organic matter into simpler substances and convert it into a solution. The saprophytes absorb the solution and obtain nutrition.Answer
Aim: To prove that light is required for the process of photosynthesis.Answer
Material required: A potted plant, black paper and materials for the starch Test (Iodine solution).
Procedure:
(i) Keep a potted plant in a dark room for 24 to 48 hours.
(ii) Before keeping it out in sunlight, cover one of the leaves with black paper.
(iii) Leave the experimental setup in the sunlight for 6 to 8 hours.
(iv) Pluck two leaves, the one that was covered with black paper and any other healthy leaf from the plant.
(v) Now test the leaf for starch by iodine solution.
Observation: The leaf covered with black paper shows a negative result for the starch test (does not turn blue black in colour), whereas the other healthy leaf tests positive for starch ( turn blue black in colour).
Conclusion: The above experiment shows that sunlight is required for the process of photosynthesis.
Aim: To test for the presence of starch in a leaf after photosynthesis.Answer
Answer
Material required: Iodine, a dropper, Bunsen burner, test tube, beaker, alcohol, white trey, potted plant.
Procedure:
(i) Keep a healthy potted plant in darkness for about 20 to 48 hours.
(ii) Pluck out a leaf of this plant before you keep it out in sunlight. This is leave A, which is your control.
(iii) Now pluck another leaf from the plant after it has been in sunlight for at least one to two hours. This is a leaf B, which is your experimental leaf.
(iv) Place both the leaves in a beaker containing hot water for a few minutes. Then take them out of the beaker. Pour alcohol in a test tube and immerse the two leaves in it.Keep the test tube inside a 1 litre beaker containing water and hea it.
(v) When the alcohol starts to boil, green colour comes out of the leaves and the chlorophyll starts to dissolve in the alcohol.
(vi) Take out the leaves and watch them in water to remove the alcohol.
(vii)Place the leaves on the white trey and add a drop of iodine on the leaves by the help of a dropper.
Observation: You will observe that Leaf A does not change its colour, whereas the colour of leaf B changes to blue-black, thereby indicating the presence of starch in it.