According to new CBSE Exam Pattern, MCQ Questions for Class 10 Science pdf Carries 20 Marks.

Topics and Subtopics in NCERT Solutions for Class 10 Science Chapter 6 Life Processes:

Question-1
Define nutrition? What are the different modes of nutrition?
Solution:
Nutrition is the process of intake, as well as utilization of nutrients by an organism. The different modes of nutrition are saprophytic nutrition, parasitic nutrition and holozoic nutrition.
Question-2
What is the mode of nutrition in fungi?
Solution:
Saprophytic nutrition is the mode of nutrition that is seen in fungi.

Question-3
Name the pigment, which can absorb solar energy.
Solution:
Chlorophyll is the pigment, which can absorb solar energy.
Question-4
Name the two stages in photosynthesis.
Solution:
The two stages in photosynthesis are
(i) Light reaction and
(ii) Dark reaction.
Question-5
Name the factors, which affect photosynthesis.
Solution:
The factors which affect photosynthesis, are light, water, temperature, humidity, age of the leaf and carbon dioxide.
Question-6
Define a herbivore and a carnivore.
Solution:
The animals that feed only on plants are called herbivores.
The animals that feed only on flesh are called carnivores.
Question-7
How does amoeba engulf its food?
Solution:
Amoeba engulfs its food by extending pseudopodia. This process is known as Phagocytes.
Question-8
Name the parts of the digestive system of a grasshopper.
Solution:
The parts of digestive system of a grasshopper are pharynx, salivary glands, hepatic caeca, malpighian tubules, ileum, colon, rectum and anus.
Question-9
What are the functions of the liver and the pancreas?
Solution:
The liver secretes bile, which contains bile pigments and bile salts. The bile secreted by the liver cells is normally stored in the gall bladder, until needed in the duodenum. Pancreas lie parallel to and beneath the stomach. It is a large gland, which secretes digestive enzymes as well as the hormones, insulin and glucagons. Both bile and pancreatic juice enter duodenum through a common duct. Bile emulsifies fat present in the food. Pancreatic juice contains trypsin, for digesting proteins and pancreatic amylase for the breakdown of starch.
Question-10
Define breathing.
Solution:

Breathing is a process by which organisms inhale oxygen. The inhaled oxygen gets diffused into the blood and the carbon dioxide from the blood diffuses back into the alveoli from where it is exhaled.

Question-11
How is respiration different from breathing?
Solution:
Respiration is a complex process, which includes breathing, the mechanism of exchange of gases,oxygen and carbon dioxide and oxidation of digested food occurring in the cells in order to release energy. The main outcome of respiration is the release of energy through oxidation of simple food molecules such as glucose.
Question-12
In which kind of respiration is more energy released?
Solution:
In aerobic respiration more energy is released.
Question-13
Which part of the roots is involved in exchange of respiratory gases?
Solution:
Root hair is the part of the root which is involved in exchange of respiratory gases.
Question-14
What are (i) stomata and (ii) lenticels?
Solution:
(i) Stomata are tiny apertures found on the surface of the leaf, which regulate the exchange of respiratory gases and transpiration.
(ii) Lenticels are the raised pores in the woody plants that allow the exchange of gases between the atmosphere and the internal tissues.
Question-15
Give two points of differences between respiration in plants and respiration in animals.
Solution:
The respiration in plants differ from respiration in animals in two respects, they are
(i) There is minimal transport of gases from one part of the plant to another, unlike the animals.
(ii) Plant respiration occurs at a much slower rate than animal respiration.
Question-16
Name the respiratory organs of
(i) fish
(ii) mosquito
(iii) earthworm
(iv) dog
Solution:
The respiratory organs of
(i) fish – gills
(ii) mosquito – tracheoles
(iii) earthworm – skin
(iv) dog – lungs.
Question-17
Solution:
The oxygen rich air enters through openings called spiracles situated on the sides of the body of an insect. Spiracles open into tracheal system. Trachea branch into tracheoles, which reach the cells. Thus, every cell gets oxygen directly. Carbon dioxide released by cells moves out through the spiracles.
Question-18
From where do the following take in oxygen?
(i) prawn (ii) rat.
Solution:
(i) Prawns take in oxygen that is dissolved in water.
(ii) Rat takes in oxygen from the atmosphere.
Question-19
State the function of epiglottis.
Solution:
Epiglottis prevents the food from entering into the trachea.
Question-20
Solution:
The walls of trachea do not collapse when there is less air in it, because, they are supported by rings of cartilage.
Question-21
Solution:
Nutrition is the sum of all those activities which are concerned with ingestion, digestion, absorption of digested food, egestion, oxidation of simple food to produce energy for growth, development and maintenance of living organism.
Question-22
Solution:
Energy is required by an organism even during sleep because various biological processes keep on occurring in its body.
Question-23
Define photolysis.
Solution:
The phenomenon of breaking down of water in the illuminated chloroplast is known as photolysis.
Question-24
What are the living organisms that cannot make their own food called?
Solution:
The living organisms that cannot make their own food called heterotrophs.
Question-25
What are chemotrophs?
Solution:
Chemotrophs are organisms, which do not require light. They manufacture their food from inorganic substances in the presence of energy derived from the oxidation of simple inorganic compounds of iron, sulphur, etc.
e.g. bacterium Nitrosomonas.
What is compensation point?
Solution:

The compensation point is the amount of light on the light curve where the rate of photosynthesis exactly matches the rate of respiration.
At this point, the uptake of CO₂ through photosynthetic pathways is exactly matched to the respiratory release of carbon dioxide, and the uptake of O₂ by respiration is exactly matched to the photosynthetic release of oxygen. This point is reached during early mornings and late evenings.

Other than chlorophyll, which other pigment is necessary for photosynthesis?
Solution:
Carotenoids are the pigments, which are necessary for photosynthesis other than chlorophyll. Carotenoids are yellow, orange, red or brown pigments, which absorb sunlight and pass this energy on to chlorophyll for the purpose of photosynthesis. Thus, the carotenoids themselves do not carry out photosynthesis but help in photosynthesis.
Question-28
Where does digestion begin?
Solution:
Digestion begins from the mouth.
Question-29
What is the name given to the process of using the absorbed food for producing energy?
Solution:
The name given to the process of using the absorbed food for producing energy is assimilation.
Question-30
What happens to visible light of the Sun when it falls on chlorophyll?
Solution:
Visible light of the Sun consists of seven colours, namely, violet, indigo, blue, green, yellow, orange and red. Out of these lights of different wave lengths, chlorophyll absorbs mainly blue, violet, red and orange lights but does not absorb the green light. It is due to the reflection of green light by the chlorophyll that the plant looks green in colour.