DAV Class – 7 Science Book Solutions Chapter -1 Nutrition in Living Organisms-Plants
If you are looking for DAV Class – 7 Science Book Solutions Chapter -1 Nutrition in Living Organisms-Plants then you are at right place. DAV class 7 Science chapter 1 question answer is given below. Here we provide complete solution of DAV class Seven the Living World science book.
A. Fill in the blanks.
1. Animals are ___________ as they cannot synthesis their own food.
2. The ___________, of a plant, absorb water and minerals from the soil.
3. During photosynthesis plants take in ___________ and release ___________.
4. ___________ are the tiny pores through which leaves exchange gases.
5. Insect eating plants are called ___________ plants.
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: (1) Heterotrophs (2) roots (3) Carbon dioxide, Oxygen (4) Stomata (5) insectivorous (6) (a) water (b) Carbon dioxide
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
C. Tick the correct option.
(1) autotrophs (2) leaf (3) pitcher plant (4) saprotroph (5) rhizobium
D. Answer the following questions in brief.
1. Why is nutrition important for a living organism?
Answer: Nutrition is important because it enable living organisms to build their bodies, to grow, to repair damaged parts of their bodies and to provide the energy to carry out life processes.
2. How do green plants synthesis their food?
Answer: Green plants synthesis their food by the process of photosynthesis.
3. State the role of ‘vessels’ present in a plant.
Answer: Vessels help in transportation of water and minerals to other parts of the plant.
4. Define the following terms:
(a) Symbiotic relationship
Answer: Symbiotic relationship – Sometimes two organisms live in close association and develop a relationship that is beneficial to both. This is called symbiotic relationship.
Answer: Nutrients – Components of food such as carbohydrates, proteins, fats, vitamins and minerals which are necessary for our body are called nutrients.
(c) Saprotrophic mode of nutrition
Answer: Saprotrophic mode of nutrition – Saprotrophic nutrition is the process in which the organisms feed on dead and decaying matter.
Answer: Photosynthesis – The process through which green plants prepare their own food are called photosynthesis.
5. When some wheat dough was left in the open for a few days, it started emitting a foul smell. State, why?
Answer: The wheat dough was left in the open for a few days, it started emitting a foul smell due to the action of fungi and bacteria that grow on it. These organisms are called Saprotrophs which obtain food from dead and decaying organic matter.
E. Answer the following questions.
1. Why would life not be possible on the earth in the absence of photosynthesis?
Answer: Plants make their food by the process of photosynthesis. In the absence of photosynthesis there would be no plants and oxygen gas would not be released into the atmosphere which is essential for respiration. All animals directly or indirectly dependent on plants. So, life would not be possible on the earth in the absence of photosynthesis.
2. Give reasons for the following:
(a) Mushroom is a saprotroph.
Answer: Mushroom does not contain chlorophyll so it does not make their own food by photosynthesis. It gets its food from dead and decaying matter due to which it is known as Saprotroph.
(b) Sun is the ultimate source of energy for all living organisms.
Answer: Plants use sunlight to make their food by the process of photosynthesis. This food is then consumed by all the animals and human beings directly or indirectly. Hence, Sun is the ultimate source of energy.
(c) The leaf of a plant ‘dies out’ if its stomata are blocked.
Answer: Stomata help in photosynthesis by exchanging the gases like oxygen and Carbon dioxide. If stomata of a leaf are blocked, it does not make their food and the leaf dies out.
(d) Leaf is known as the food factory of the plant.
Answer: The leaf of a plant synthesizes its food by the process of photosynthesis. Hence, it 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 living partnership between a fungus and an alga. The fungus absorbs water and provides shelter. The alga prepares food by photosynthesis. Hence, this partnership is beneficial to both.
3. Why do some plants feed on insects? How does a pitcher plant catch insects?
Answer: Some plants feed on insects for their nitrogen requirements. These plants are called insectivorous plants. Pitcher plant is an example of this type of plant. The leaf of this plant gets modified to form a pitcher with a lid. When an insect enters, it cannot climb back out against the hairs and ultimately falls to the bottom of the leaf, and gets digested by the juices present there.
4. How do rhizobium bacteria and leguminous plants help each other in their survival?
Answer: Rhizobium is a bacterium that lives in the roots of leguminous plants. It converts nitrogen, from the atmosphere, into a usable form that can be utilised by the plants. The plants, in turn, provide food and shelter to the bacterium.
5. Complete the web chart.