The DAV Class 7 Science Book Solutions Pdf and DAV Class 7 Science Chapter 1 Question Answer – Nutrition in Living Organisms: Plants are essential study tools for DAV public school students in Class 7.
DAV Class 7 Science Ch 1 Question Answer – Nutrition in Living Organisms: Plants
DAV Class 7 Science Ch 1 Solutions – Nutrition in Living Organisms: Plants
Something to Know
A. Fill in the blanks.
Question 1.
Animals are ________ as they cannot synthesise their own food.
Answer:
heterotrophs
Question 2.
The ________ of a plant, absorb water and minerals from the soil.
Answer:
roots
Question 3.
During photosynthesis plants take in ________ and release ________
Answer:
carbon dioxide, oxygen
Question 4.
________ are tiny pores through which leaves exchange gases.
Answer:
stomata
Question 5.
Insect eating plants are called ________ plants.
Answer:
Question 6.
An essential raw material needed for the process of photosynthesis, and
(a) Available in the soil is ________
(b) Available in the air is ________
Answer:
insectivorous
B. Match the following:
| 1. Chlorophyll | a) Autotrophs |
| 2. Lichens | b) Saprotrophs |
| 3. Fungi | c) Symbiotic relationship |
| 4. Amarbel | d) Leaf |
| 5. Plants | e) Parasite |
Answer:
| 1. Chlorophyll | a | Autotrophs |
| 2. Lichens | b | Saprotrophs |
| 3. Fungi | c | Symbiotic relationship |
| 4. Amarbel | d | Leaf |
| 5. Plants | e | Parasite |
C. Tick (✓) the correct option.
1. Green plants, that can synthesise their own food, are known as-
(a) Heterotrophs
(b) Parasites
(c) Autotrophs
(d) Saprotrophs
Answer:
(c) Autotrophs
2. Food factory, of the plant, is its
(a) Root
(b) Flower
(c) Stem
(d) Leaf
Answer:
(d) Leaf
3. Which of the following is an insectivorous plant?
(a) Pitcher plant
(b) Leguminous plant
(c) Green plant
(d) Amarbel
Answer:
(a) Pitcher plant
4. Mushroom is an example of a/an
(a) Saprotroph
(b) Parasite
(c) Autotroph
(d) Cuscuta
Answer:
(a) Saprotroph
5. An organism, that fixes nitrogen in the soil, is
(a) Mushroom
(b) Mucor
(c) Rhizobium
(d) Cuscuta
Answer:
(c) Rhizobium
D. Answer the following questions in brief.
Question 1.
Why is nutrition important for living organism?
Answer:
All living beings carry out various life processes to maintain and continue their life. Carrying out the life processes can be possible only by continuous supply of energy and raw materials. Organisms need to get nutrition to get energy and raw materials for various life processes.
Question 2.
How do green plants synthesise their food?
Answer:
Green plants take water and carbon dioxide and take energy from sunlight. With the help of these things, green plants prepare their food in leaves; where chlorophyll helps in trapping the solar energy.
Question 3.
State the role of Vessels’ present in a plant.
Answer:
Role of vessels in plant is transportation of water and minerals.
Question 4.
Define the following terms:
(a) Symbiotic relationship
Answer:
The relation between two organisms in which both benefit each other is called symbiotic relationship.
(b) Nutrients
Answer:
Matters which are essential components of food are called nutrients.
(c) Saprotrophic mode of nutrition
Answer:
The mode of nutrition in which a living being feeds on dead remains of plants and animals is called saprotrophic nutrition. In this case, the digestion of food takes place before ingestion.
(d) Photosynthesis
Answer:
Photosynthesis is the process by which green plants prepare their own food.
Question 5.
When some wheat dough was left in the open for a few days, it started emitting a foul smell. State, why?
Answer:
When some wheat dough is left in the open for a few days, then microbes start growing on it. These microbes decompose the dough. Due to this, the dough starts emitting foul smell.
E. Answer the following questions.
Question 1.
Why would life not be possible on the earth in the absence of photosynthesis?
Answer:
We know that all living beings depend for food on green plants and so on
photosynthesis. In case of absence of green plants on the earth, no organism would be able to get its food. Hence, life would be impossible on the earth in the absence of photosynthesis.
Question 2.
Give reasons for the following:
(a) Mushroom is a saprotroph.
Answer:
Mushroom feeds on dead and decaying remains by extracellular digestion. Hence, mushroom is a sapro troph.
(b) Sun is the ultimate source of energy for all living organisms.
Answer:
We know that green plants trap solar energy to prepare food and all other living beings depend on green plants for food. Thus, all other living beings take energy from green plants in which energy comes from the sun. Due to this, sun is the ultimate source of energy.
(c) The leaf of a plant ‘dies out’ if its stomata are blocked.
Answer:
Stomata are tiny pores through which carbon dioxide comes in the leaves and water vapour goes out. Intake of carbon dioxide and expulsion of water vapour is necessary for photosynthesis in leaves. Moreover, stomata also facilitate breathing leaves. So, this is clear that the leaf of a plant will die if its stomata are blocked.
(d) Leaf is known as the food factory of the plant.
Answer:
Plants usually prepare food in their leaves. Hence, leaf is known as the food factory of the plant.
(e) Lichen is a “living partnership’ between a fungus and an alga and this “partnership’ is beneficial to both.
Answer:
Lichen is a combination of a fungus and an alga. The fungal part absorbs water and mineral from the substratum, while the algal part carries out photosynthesis to prepare food. Thus, both partners benefit each other in this association.
Question 3.
Keep a stale, moist piece of bread in a warm comer of the kitchen and observe it for 3-4 days. Can you identify the organism on the piece of bread? Identify its mode of nutrition.
Answer:
Do this activity yourself. Bread mould (Rhizopus) grows on bread and it shows saprophytic nutrition.
Question 4.
Solve the crossword puzzle with the help of the clues given below.
Across:
1. A plant parasite.
2. The process by which green plants prepare their food.
3. The process of obtaining, and utilising, food.
4. Green pigment present in the leaves of plants.
Answer:
- Cuscuta,
- Photosynthesis,
- Nutrition,
- Chlorophyll
Down:
1. Two different organisms that live together and thereby, benefit from each other.
2. Organism feeding on dead matter.
3. An organism deriving food from another living organism.
Answer:
Organisms that cannot prepare its own food.
DAV Class 7 Science Chapter 1 Solutions – Nutrition in Living Organisms: Plants
I. Fill in the blanks.
Question 1.
Carbohydrate is a compound of ________, ________ and hydrogen.
Answer:
Carbon, Oxygen
Question 2.
________is an important component of protein.
Answer:
Nitrogen
Question 3.
________ traps solar energy in green plants.
Answer:
Chlorophyll
Question 4.
After photosynthesis, carbohydrate is converted into
Answer:
Starch
Question 5.
Lichen shows ________ relationship of algae and fungi.
Answer:
Symbiotic
Question 6.
Cuscuta is an example of a ________
Answer:
Parasite
II. State whether the following statements are true or false.
1. Energy is “locked’ in the form of solar energy in food.
2. Cuscuta derives its nutrition from another plant.
3. Roots help in absorption of carbon dioxide.
4. Carbohydrate and oxygen are the products of photosynthesis.
5. All living organisms depend on plants.
Answer:
1. Energy is “locked’ in the form of solar energy in food. (False)
2. Cuscuta derives its nutrition from another plant. (True)
3. Roots help in absorption of carbon dioxide. (False)
4. Carbohydrate and oxygen are the products of photosynthesis. (True)
5. All living organisms depend on plants. (True)
III. Match the following:
| Column A | Column B |
| 1. Chlorophyll | (a) Insect eater |
| 2. Nitrogen | (b) Heterotrophs |
| 3. Animals | (c) Rhizobium |
| 4. Amarbel | (d) Leaf |
| 5. Pitcher plant | (e) Parasite |
Answer:
| Column A | Column B | ||
| 1. Chlorophyll | d | (a) Insect eater | |
| 2. Nitrogen | c | (b) Heterotrophs | |
| 3. Animals | b | (c) Rhizobium | |
| 4. Amarbel | e | (d) Leaf | |
| 5. Pitcher plant | a | (e) Parasite |
IV. Tick (✓) the correct option.
1. Which of the following gases is one of the raw materials for photosynthesis?
(a) Oxygen
(b) Carbon dioxide
(c) Nitrogen
(d) Hydrogen
Answer:
(b) Carbon dioxide
2. Which gas is produced after photosynthesis?
(a) Oxygen
(b) Carbon dioxide
(c) Nitrogen
(d) Hydrogen
Answer:
(a) Oxygen
3. Which of these is a parasitic plant?
(a) Grass
(b) Pitcher plant
(c) Cuscuta
(d) Mushroom
Answer:
(c) Cuscuta
4. A pitcher plant traps insects to get which of these substances?
(a) Oxygen
(b) Carbon
(c) Hydrogen
(d) Nitrogen
Answer:
(d) Nitrogen
5. The bread mould belongs to which of these groups of organisms?
(a) Green plants
(b) Fungi
(c) Bacteria
(d) Animals
Answer:
(b) Fungi
6. Lichen is a combination of which of these pairs?
(a) Algae and fungi
(b) Algae and bacteria
(c) Fungi and bacteria
(d) Animal and fungi
Answer:
(a) Algae and fungi
V. Answer the following questions.
Question 1.
Write the names of essential nutrients.
Answer:
Carbohydrates, proteins, fats, vitamins and minerals.
Question 2.
What do you understand by autotrophic nutrition?
Answer:
The mode of nutrition in which a living being makes its own food is called autotrophic nutrition. All green plants and some bacteria are autotrophs.
Question 3.
What do you understand by heterotrophic nutrition?
Answer:
The mode of nutrition in which a living being depends on others for food is called heterotrophic nutrition. All animals and non-green plants are heterotrophs.
Question 4.
Write the equation to show photosynthesis.
Answer:
Question 5.
Write a brief note on insectivorous plants.
Answer:
Some plants which grow in marshy swamps do not get nitrogen because the soil is nitrogen deficient in such areas. Such plants trap insects and suck their juices to fulfill their need for nitrogen. Pitcher plant and Venus Fly Trap are examples of insectivorous plants.
Question 6.
Write a brief note on symbiotic relationship in lichen.
Answer:
Lichens present a very good example of symbiotic relationship. Lichen is a combination of two types of organisms, i.e. algae and fungi. The fungal part absorbs water and mineral from the substratum, while the algal part carries out photosynthesis to prepare food.
VI. Projects
Question 1.
Collect photographs of Pitcher Plant and Venus Fly Trap and paste them in your scrapbook.
Answer:
Do it yourself.
Question 2.
Arrange an experiment to show that photosynthesis takes place in leaves. You can take help of your teacher.
Answer:
Do it yourself.
Question 3.
Write an essay on importance of forests for us.
Answer:
Do it yourself.
Question 4.
How does the soil replenish its lost nutrients?
Answer:
We know that plants get many nutrients from soil and thus sap the soil off nutrients. Some bacteria live in soil and help in nitrogen fixation in the soil. Thus, replenishment of nutrients takes place in soil through nitrogen fixation. Sometimes, farmers also sprinkle fertilisers and manures to replenish nutrients in soil.