Class 7 Nutrition in Plants Important Questions VBQs

Question. Kumud planned to replace her kitchen garden with some SHRUBS. Identify which plants she could have chosen.
(a) Hibiscus, Rose, Bougainvillea, Henna
(b) Rose, Balsam, Jasmine, Tulsi
(c) Bougainvillea, Henna, Lemon, Papaya
(d) Marigold, Tiger-Lily, Henna, Balsam

Assignment- 1.1

Fill in the blanks: [16 Marks]

1. The components of food that are necessary for our body are called _______________. [1 Mark]

Answer: nutrients.

Teacher's Note:
a) Nutrients provide nourishment essential for growth and maintenance.
b) Recall the major dietary components.

2. The components of food include ________________, _______________, ________________, _________________ and _________________. [1 Mark]

Answer: carbohydrates, proteins, fats, vitamins, minerals.

Teacher's Note:
a) These five make up the primary nutrient groups required by living organisms.
b) Water and dietary fibres are also essential components of our diet.

3. ______________ and ________________ are directly or indirectly dependent on plants. [1 Mark]

Answer: Animals, humans (or herbivores, carnivores).

Teacher's Note:
a) Green plants are producers that form the base of all food chains.
b) Carnivores depend indirectly through herbivores.

4. _______________are the only organisms that can prepare their own food using __________, _____________, _____________, and ________________. [1 Mark]

Answer: Plants, water, carbon dioxide, minerals, sunlight.

Teacher's Note:
a) Plants perform photosynthesis using raw materials from their surroundings.
b) Sunlight acts as the energy source for this chemical process.

5. _________________ is the mode of taking food by an organism and its utilization by the body. [1 Mark]

Answer: Nutrition.

Teacher's Note:
a) Nutrition encompasses ingestion, digestion, absorption, and assimilation.
b) Distinguish between nutrition and simple feeding.

6. The green pigment in leaves is called _______________. [1 Mark]

Answer: chlorophyll.

Teacher's Note:
a) Chlorophyll absorbs solar energy to drive photosynthesis.
b) It is located inside chloroplasts.

7. _______________ which is essential for the survival of all organisms is produced during photosynthesis. [1 Mark]

Answer: Oxygen.

Teacher's Note:
a) Oxygen is released as a byproduct during photolysis of water.
b) All aerobic organisms require oxygen for respiration.

8. During photosynthesis plants synthesize _________________, which ultimately gets converted into _____________. [1 Mark]

Answer: carbohydrate (or glucose), starch.

Teacher's Note:
a) Simple sugars produced are stored in the form of complex carbohydrates.
b) Presence of starch in leaves indicates occurrence of photosynthesis.

9. Slimy, green patches in ponds and other stagnant water bodies are due to the growth of organisms called _______________. [1 Mark]

Answer: algae.

Teacher's Note:
a) Algae contain chlorophyll and are autotrophic organisms.
b) They multiply rapidly in nutrient-rich stagnant water.

10. Carbohydrates are made of ______________, _______________ and ________________. [1 Mark]

Answer: carbon, hydrogen, oxygen.

Teacher's Note:
a) Organic compounds composed of these three elements form sugars and starches.
b) Remember the chemical constituents of basic food molecules.

11. ______________ are nitrogenous substances that contain nitrogen. [1 Mark]

Answer: Proteins.

Teacher's Note:
a) Proteins are macromolecules containing amino acids with nitrogen.
b) Plants absorb nitrogen from soil to synthesize proteins.

12. Soil has certain ________________ that convert gaseous nitrogen into usable form and release it into the soil. [1 Mark]

Answer: bacteria (such as Rhizobium).

Teacher's Note:
a) Atmospheric nitrogen cannot be utilized directly by plants.
b) Biological nitrogen fixation enriches soil fertility.

13. Cuscuta (Amerbel) uses ____________________ mode of nutrition. [1 Mark]

Answer: parasitic.

Teacher's Note:
a) Parasites depend completely on a host plant for ready-made food.
b) Cuscuta lacks chlorophyll and special roots called haustoria absorb nutrients.

14. The Pitcher plant eats _______________ and is hence a _____________________ plant. [1 Mark]

Answer: insects, insectivorous.

Teacher's Note:
a) Insectivorous plants grow in nitrogen-deficient soils.
b) Modified leaves trap insects to supplement nitrogen requirements.

15. _________________ are organisms that have no chlorophyll and no mouth like animals and feed on dead and decaying organic matter. [1 Mark]

Answer: Fungi (or saprotrophs).

Teacher's Note:
a) Saprotrophic nutrition involves secreting digestive juices onto dead matter.
b) Nutrients are absorbed in a solution form.

16. Some organisms live together and share shelter and nutrition. This is called _____________relationship. [1 Mark]

Answer: symbiotic.

Teacher's Note:
a) Symbiosis provides mutual benefit to both participating species.
b) Examples include lichens and Rhizobium association in root nodules.

17. The organism Lichen has a symbiotic relationship between an ______________ and a ________________ [1 Mark]

Answer: alga, fungus

Teacher's Note:
a) Lichens show a mutualistic symbiotic association where an alga and a fungus live together.
b) The algal partner provides food prepared by photosynthesis, while the fungal partner provides shelter, water, and minerals.

18. _________________ and _________________ are essential requirements for photosynthesis. [1 Mark]

Answer: Carbon dioxide, Water (or Sunlight, Chlorophyll)

Teacher's Note:
a) Photosynthesis requires raw materials like carbon dioxide and water, along with sunlight and chlorophyll.
b) Students should remember all four key components required for the food-making process in plants.

19. ___________ energy is stored in the form of food in the leaves with the help of chlorophyll. [1 Mark]

Answer: Solar (or Light)

Teacher's Note:
a) Chlorophyll traps solar energy from sunlight to convert it into chemical energy during photosynthesis.
b) This captured energy is stored as food in plant leaves.

20. During photosynthesis plants take in _____________ and release __________________ into the air. [1 Mark]

Answer: carbon dioxide, oxygen

Teacher's Note:
a) Plants absorb carbon dioxide from the atmosphere through stomata for photosynthesis.
b) Oxygen is released as a byproduct during this vital life process.

Answer the following:

1. Where do plants synthesize their food? [1 Mark]

Answer: Plants synthesize their food in their leaves, which are considered the food factories of the plant.

Teacher's Note:
a) Leaves contain the green pigment chlorophyll that absorbs sunlight for synthesis.
b) Green stems can also perform photosynthesis in some plants.

2. Why are algae green in colour? Where do they grow? [2 Marks]

Answer:
1. Algae are green in colour because they contain a green pigment called chlorophyll.
2. They usually grow in moist, damp areas such as stagnant water bodies, ponds, and wet walls.

Teacher's Note:
a) Chlorophyll gives algae their characteristic green appearance and allows them to make their own food by photosynthesis.
b) Common habitats include ponds, lakes, and moist rocks.

3. What are the various components of food? [1 Mark]

Answer: The various components of food are carbohydrates, proteins, fats, vitamins, and minerals, which are known as nutrients.

Teacher's Note:
a) Nutrients are essential for living organisms to build their bodies, grow, repair damaged parts, and provide energy.

4. Why do organisms need to take food? [2 Marks]

Answer:
1. Organisms need food to get energy for carrying out various life processes and daily activities.
2. Food is essential for the growth, development, and repair of damaged body parts.

Teacher's Note:
a) Nutrients from food act as fuel for the body.
b) Proper nutrition also helps build resistance against diseases.

5. Name the pores through which leaves exchange gases. [1 Mark]

Answer: Stomata

Teacher's Note:
a) Stomata are tiny pores present generally on the underside of plant leaves.
b) They are guarded by guard cells that regulate their opening and closing.

6. How does the following raw material reach the leaves of a plant for preparing food:
a. Water and minerals
b. Carbon-dioxide: [2 Marks]

Answer:
1. Water and minerals are absorbed by the roots and transported to the leaves through vessel-like tubes running through the root, stem, branches, and leaves.
2. Carbon dioxide is taken in from the air through tiny pores called stomata present on the surface of leaves.

Teacher's Note:
a) Xylem vessels are responsible for transporting water and minerals upwards.
b) Gaseous exchange happens directly via diffusion through the stomatal openings.

7. Explain photosynthesis in brief. Give an equation to represent the process. [3 Marks]

Answer:
1. Photosynthesis is the process by which green plants prepare their own food using carbon dioxide and water in the presence of sunlight and chlorophyll.
2. Oxygen is released as a byproduct during this process.
3. Equation: Carbon dioxide + Water \(\xrightarrow{\text{Sunlight / Chlorophyll}}\) Carbohydrate + Oxygen

Teacher's Note:
a) It is a unique process that converts solar energy into chemical energy.
b) Life on Earth depends directly or indirectly on photosynthesis.
c) Mentioning both the word equation and conditions is essential for full credit.

8. If two similar potted plants A & B are taken such that:
Plant A is kept in the dark or a black box for 72 hours (3 days),
Plant B is kept in sunlight.
Iodine test is conducted with the leaves of both plants.
Which plant leaf tests positive for the test and Why? [3 Marks]

Answer:
1. Plant B leaf tests positive for the iodine test.
2. Plant B was kept in sunlight, allowing it to perform photosynthesis and synthesize starch.
3. Plant A was kept in the dark, so it could not perform photosynthesis and hence contains no starch to react with iodine.

Teacher's Note:
a) Iodine turns blue-black in the presence of starch.
b) Sunlight is an absolute requirement for starch formation in leaves.
c) Keeping plant A in the dark helps destarch its leaves before experimental verification.

9. Why is the sun considered as the ultimate source of energy for all things? [2 Marks]

Answer:
1. The sun provides solar energy which is trapped by green plants during photosynthesis to manufacture food.
2. All animals and non-green organisms depend directly or indirectly on plants for their food and energy requirements.

Teacher's Note:
a) Solar energy is the foundational input for nearly all food chains on Earth.
b) Without the sun, life and energy flow through living systems would cease.

10. Define the following and give one example of each:
a. Autotrophic nutrition
b. Heterotrophs [3 Marks]

Answer:
1. Autotrophic nutrition: A mode of nutrition in which organisms make food themselves from simple substances. Example: Green plants (e.g., Mango tree).
2. Heterotrophs: Organisms that take in food prepared by plants directly or indirectly. Example: Humans (or Animals).

Teacher's Note:
a) 'Auto' means self and 'troph' means nourishment; autotrophs are producers.
b) 'Hetero' means other; heterotrophs rely on other living beings for sustenance.
c) Providing correct definitions alongside suitable examples secures full marks.

11. Label the following diagram of stomata: [2 Marks]

Answer:
1. The main labels of a stomatal diagram are: Guard cells, Stomatal aperture (pore), Chloroplasts, and Epidermal cells.
2. Guard cells are kidney-shaped cells that enclose and control the opening and closing of the stomatal pore.

Teacher's Note:
a) Clear and neat labeling of structural components is vital for diagram-based questions.
b) Guard cells swell or shrink to open or close the stoma for gaseous exchange.

12. Give the mode of nutrition for the following: [5 Marks]
a. Amerbel      b. Rose      c. Pitcher plant      d. Deer      e. Cow
f. Mushroom      g. Pig      h. Cabbage      i. Yeast      j. Man

Answer:
1. a. Amerbel: Parasitic nutrition
2. b. Rose: Autotrophic nutrition
3. c. Pitcher plant: Insectivorous (Autotrophic and Heterotrophic)
4. d. Deer: Heterotrophic (Herbivore)
5. e. Cow: Heterotrophic (Herbivore)
6. f. Mushroom: Saprophytic nutrition
7. g. Pig: Heterotrophic (Omnivore)
8. h. Cabbage: Autotrophic nutrition
9. i. Yeast: Saprophytic nutrition
10. j. Man: Heterotrophic (Omnivore)

Teacher's Note:
a) Autotrophs prepare their own food using sunlight, water, and carbon dioxide.
b) Heterotrophs depend directly or indirectly on plants for their nutrition.
c) Parasites derive nutrients from a living host organism without killing it immediately.
d) Saprotrophs feed on dead and decaying organic matter by secreting digestive juices.

MULTIPLE CHOICE QUESTIONS

1. Plants take carbon dioxide from air during photosynthesis from [1 Mark]
a. root hair
b. leaves
c. water
d. flowers

Answer: (b) leaves

1. Leaves contain tiny pores called stomata.
2. Carbon dioxide from the air enters the plant through these stomata present on leaves.
3. Hence, the correct option is (b).

Teacher's Note:
a) Stomata are surrounded by guard cells that regulate their opening and closing.
b) Students often confuse the whole leaf surface with the specific microscopic pores called stomata.

2. Presence of starch can be tested by [1 Mark]
a. alcohol
b. iodine
c. water
d. hydrochloric acid

Answer: (b) iodine

1. Iodine reacts with starch to form a blue-black colored complex.
2. Alcohol is used to decolourize the leaf during the test.
3. Hence, the correct option is (b).

Teacher's Note:
a) Iodine test is the standard chemical test to confirm the presence of carbohydrates like starch.
b) A blue-black color change indicates a positive test result for starch.

3. Which part of plant gets CO2 from air during photosynthesis [1 Mark]
a. root hair
b. sepal
c. stomata
d. leaf vein

Answer: (c) stomata

1. Gaseous exchange for photosynthesis takes place through leaves.
2. Carbon dioxide enters through tiny pores known as stomata.
3. Hence, the correct option is (c).

Teacher's Note:
a) Stomata are specialized structures primarily located on the underside of leaves.
b) Root hairs absorb water and minerals from the soil, not gases from the air.

4. Green plants are also known as [1 Mark]
a. autotrophs
b. heterotrophs
c. carnivores
d. saprophytes

Answer: (a) autotrophs

1. Plants synthesize their own food using simple inorganic substances.
2. Organisms that make their own food are called autotrophs.
3. Hence, the correct option is (a).

Teacher's Note:
a) The prefix 'auto' means self and 'troph' means nourishment.
b) Green plants use chlorophyll to convert light energy into chemical energy.

5. The green pigment in leaves help to [1 Mark]
a. make food
b. absorb water
c. absorb sunlight
d. take in CO2

Answer: (c) absorb sunlight

1. Leaves contain a green pigment called chlorophyll.
2. Chlorophyll captures solar energy required to synthesize food.
3. Hence, the correct option is (c).

Teacher's Note:
a) Chlorophyll is responsible for the green color of plant leaves.
b) Water absorption is primarily performed by the root system.

6. In a cactus plant, the part responsible for photosynthesis is [1 Mark]
a. leaf
b. thorn
c. root
d. stem

Answer: (d) stem

1. Leaves in cactus plants are modified into spines to reduce water loss.
2. Their stems are green and fleshy, taking over the function of photosynthesis.
3. Hence, the correct option is (d).

Teacher's Note:
a) Desert adaptations include spine modification to prevent excessive transpiration.
b) Photosynthesis in cacti shifts from leaves to modified green stems.

7. Which of these products is not stored as food in plants [1 Mark]
a. protein
b. vitamins
c. oxalic acid
d. oil

Answer: (c) oxalic acid

1. Proteins, vitamins, and oils are stored food materials or essential nutrients in plants.
2. Oxalic acid is a metabolic waste product or protective secondary metabolite, not a stored food reserve.
3. Hence, the correct option is (c).

Teacher's Note:
a) Plants store food reserves primarily as starch, proteins, and oils.
b) Organic acids like oxalic acid are generally present as crystals or cell sap components.

8. The simplest carbohydrate made as food during photosynthesis is [1 Mark]
a. starch
b. sugar
c. glucose
d. oil

Answer: (c) glucose

1. Photosynthesis directly produces glucose as the primary simple carbohydrate.
2. Glucose is subsequently converted into complex carbohydrates like starch for storage.
3. Hence, the correct option is (c).

Teacher's Note:
a) Glucose is a simple sugar with the chemical formula C₆H₁₂O₆.
b) Starch is a polymer of glucose molecules stored inside plant tissues.

9. Cuscuta plant can be categorized as [1 Mark]
a. parasite
b. insectivorous
c. saprophyte
d. host

Answer: (a) parasite

1. Cuscuta (Amarbel) lacks chlorophyll and cannot make its own food.
2. It climbs on host plants and derives readymade nutrients, acting as a parasite.
3. Hence, the correct option is (a).

Teacher's Note:
a) Parasitic plants develop special roots called haustoria to absorb nutrients from the host.
b) The organism providing nutrition is termed the host, not the parasite.

10. The plant that traps and feeds on insects [1 Mark]
a. cuscuta
b. china rose
c. rose
d. pitcher plant

Answer: (d) pitcher plant

1. Pitcher plants grow in nitrogen-deficient soil and trap insects to fulfill their nitrogen requirement.
2. They are classic examples of insectivorous plants.
3. Hence, the correct option is (d).

Teacher's Note:
a) Insectivorous plants are green and carry out photosynthesis for energy.
b) They trap insects inside specialized leaf modifications like pitcher-like structures.

11. The leather objects that are kept in hot humid weather for a long time are spoiled due to the growth of [1 Mark]
a. algae
b. yeast
c. fungi
d. moss

Answer: (c) fungi

1. Fungi grow rapidly in hot and humid weather conditions.
2. They thrive on organic matter such as leather, clothes, and wooden items.
3. Hence, the correct option is (c).

Teacher's Note:
a) Fungal spores are present in the air and germinate in moisture and warmth.
b) Leather provides organic nutrients for fungal growth.

12. The Rhizobium bacteria lives inside the root nodules of [1 Mark]
a. peas
b. beans
c. peanuts
d. all of the above

Answer: (d) all of the above

1. Rhizobium is a symbiotic bacterium that lives in the root nodules of leguminous plants.
2. Peas, beans, and peanuts are all leguminous crops.
3. Hence, the correct option is (d).

Teacher's Note:
a) Rhizobium fixes atmospheric nitrogen into usable compounds for the plant.
b) This relationship is a classic example of symbiosis.

VALUE BASED QUESTION: Reena segregates the waste at home and put the bio degradable waste in a pot containing soil. She leaves it for 15 days and uses that soil for her plants in the garden. Why do you think she did so? [3 Marks]

Answer:
1. Reena converted biodegradable household waste into compost by natural decomposition.
2. Microorganisms present in the soil break down organic waste into nutrient-rich humus.
3. Using this compost enriches the garden soil with essential nutrients, promoting healthy plant growth while practicing eco-friendly waste management.

Teacher's Note:
a) Biodegradable waste includes vegetable peels, fruit remnants, and plant leaves.
b) Composting reduces landfill waste and recycles organic matter safely.
c) Students should appreciate the role of decomposers in maintaining soil fertility.

Lab activity
Objective: To test a leaf for presence of starch. [5 Marks]
Materials required: Green leaves, Beaker, tripod stand, burner, test tube, alcohol, iodine solution, petridish, water.
Procedure:
1. Pluck a green leaf from a plant exposed to sunlight.
2. Boil the leaf in water for a few minutes to kill the cells.
3. Place the boiled leaf in a test tube containing alcohol and heat it in a water bath until the chlorophyll is completely removed and the leaf becomes colourless.
4. Wash the decolourised leaf carefully in warm water.
5. Place the leaf in a petridish and add a few drops of iodine solution over it.

Diagram:
[Figure: Experimental setup showing a burner, tripod stand, beaker with water acting as a water bath, and a test tube containing alcohol and a green leaf inside it]

Observation: The leaf turns a blue-black colour upon the addition of iodine solution.
Conclusion: The change in colour to blue-black confirms the presence of starch in the leaf, which is produced during photosynthesis.

Teacher's Note:
a) Alcohol is inflammable, so heating it directly over a burner is dangerous and a water bath must be used.
b) Boiling in water softens the leaf membrane and alcohol removes the green chlorophyll pigment so the colour change is clearly visible.
c) Iodine reacts with starch to give a characteristic blue-black complex.
d) This activity proves that leaves manufacture carbohydrates during photosynthesis.

Question. To conduct an experiment on plant growth, Lokesh added a cupful of liquid fertilizer each week to a number of plants. The unit that he used to measure the volume of the fertilizer is
(a) cubic metres.
(b) millilitres
(c) kilograms
(d) kilolitres.

Question. Ramesh hammers a nail into the trunk of a young 2m high tree about 10cm from the ground. After 2 years, the tree has grown to a height of about 5m. The nail is still on the tree. At what height from the ground will it be?
(a) about 10 cm from the ground
(b) about 2 metres from the ground
(c) it depends on the tree
(d) it depends on the tree

Question. We know that the leaves make food for a plant. When a seed is planted, before its leaves grow, where does the young plant get its food?
(a) The plant does not need food at that time.
(b) The plant gets food from the soil.
(c) The plant uses food stored in the seed.
(d) The plant uses water as food.

Question. Use the following information to answer the question:
Certain types of mushroom grow on doors which are wet after the rains. These mushrooms can be classified as :-
Autotrophs: Organisms that can prepare their own food
Heterotrophs: Organisms that depend on plants and animals for nutrition
Saprophytes: Organisms that grow on dead and decaying organic matter.
Parasites:Organisms that grow on or feed on a different organism.
(a) Autotrophs
(b) Heterotrophs
(c) Saprophytes
(d) Parasites

Question. It is known that light is not required for moist pea seeds to germinate. However, dry seeds will not germinate even if there is light. Lata sets up 4 experiments using similar pea seeds:
1. Dry pea seeds kept in light.
2. Dry pea seeds kept in the dark.
3. Moist pea seeds kept in light.
4. Moist pea seeds kept in the dark.
In which case(s) will the seeds germinate?
(a) 1 only
(b) 3 only
(c) 3 and 4 only
(d) 1 and 3 only

Question. When a carrot plant grows, the edible root and a leafy top are produced in the first year. Flowers and seeds are produced in the second year. From this we can say that the carrot plant is:
(a) an annual plant
(b) a biennial plant
(c) a triennial plant
(d) a perennial plant

Question. Mohsin and Ganesh carry out an experiment to study the effect of fertilizer use on the number of flowers produced in different plants. The results of their experiment are shown alongside. Which plant showed the highest increase and the highest percentage increase in number of flowers due to use of fertilizer?

(a) A
(b) B
(c) C
(d) D

Question. Organisms that use solar energy to make food are called producers. Which of the following lists contains all the PRODUCERS in this food web?
(a) Grasshoppers, mice, rabbits, birds, hawks and foxes
(b) Grasses, shrubs and grasshoppers
(c) Mice, rabbits and grasshoppers
(d) Grasses and shrubs

Question. What will happen to the population of grasshoppers, if the population of mice and rabbits decreases significantly?
(a) It will increase.
(b) It will decrease.
(c) It will remain the same.
(d) Cannot say.

Question. Which gas will you fill in the empty bubble here? 

(a) Nitrogen
(b) Oxygen
(c) Carbon dioxide
(d) Water vapour.

Question. Use the following information to answer the question.
One of the most common diseases a pet gets infested with is a worm infection in the stomach. 'Tape worm' is one such worm which lives off the nutrients from the stomach of an animal. Tape worms are, therefore, _______.
Autotrophs: Organisms that can prepare their own food
Heterotrophs: Organisms that depend on plants and animals for nutrition
Saprophytes: Organisms that grow on dead and decaying organic matter.
Parasites:Organisms that grow on or feed on a different organism.
(a) Saprophytes
(b) Autotrophs
(c) Heterotrophs
(d) Parasites

Question. It appears from the table that high-energy foods tend to be generally poor in ______
The following table provides details of the energy (kcal), Proteins (g), Carbohydrates (g) and Fats (g) provided by 100g of various foods. Study it and answer the question

(a) protein.
(b) fat.
(c) carbohydrates.
(d) none of these

Question. Raghuram had a meal cooked in 5g of oil. His meal consisted of 25g of dal, 100 g of cereals and a sweet made of 10g of nuts, 1g of ghee and 10 g of sugar. Use the table given below to calculate the total PROTEIN VALUE of his meal?
The following table provides details of the energy (kcal), Proteins (g), Carbohydrates (g) and Fats (g) provided by 100g of various foods. Study it and answer the question

(a) 20g
(b) 30g
(c) 40g
(d) 60g

Question. Only one of these labels actually belongs to a packet of butter. Identify the correct one

Observation: Conclusion: