NCERT Exemplar Class 10 Science Chapter 6 Life Processes

Chapter 6 Life Processes NCERT Exemplar for class 10 Science

NCERT Exemplar Solutions Class 10 Science Chapter 6 Life Processes are advance study material required for the students to score good marks in their CBSE board examinations as well as to avoid difficulty in understanding the concepts to be taught in higher secondary and graduation courses. The Class 10 Exemplar provided here consists of a set of MCQs, practice questions, value-based questions, and previous years’ questions on Life Processes.

This chapter can be called as one of the interesting chapter of class 10th which mainly deals with the maintenance processes in living organisms. In this chapter, students will learn to identify vital life processes and understand different types of nutrition as well as the respiratory organs and their mechanism, excretion, digestion, etc. To make learning more interesting and easy, we provide free access to the pdf which is available in both online and offline mode.

Access Answers to NCERT Exemplar Solutions for Class 10 Science Chapter 6 – Life Processes

1. Which of the following statements about autotrophs is incorrect?

(a) They synthesise carbohydrates from carbon dioxide and water in the presence of sunlight and chlorophyll

(b) They store carbohydrates in the form of starch

(c) They convert carbon dioxide and water into carbohydrates in the absence of sunlight

(d) They constitute the first trophic level in food chains

Soln:

The answer is (c) They convert carbon dioxide and water into carbohydrates in the absence of sunlight

Explanation:

They need sunlight to convert carbon dioxide and water into carbohydrates.

2. In which of the following groups of organisms, food material is broken down outside the body and absorbed?

(a) Mushroom, green plants, Amoeba

(b) Yeast, mushroom, bread mould

(c) Paramecium, Amoeba, Cuscuta

(d) Cuscuta, lice, tapeworm

Soln:

The answer is (b) Yeast, mushroom, bread mould

Explanation:

Yeast, mushroom and bread moulds are saprophytes, and Saprophytes break the food material outside their body and absorbed it.

3. Select the correct statement

(a) Heterotrophs do not synthesise their own food

(b) Heterotrophs utilise solar energy for photosynthesis

(c) Heterotrophs synthesise their own food

(d) Heterotrophs are capable of converting carbon dioxide and water into carbohydrates

Soln:

The answer is (a) Heterotrophs do not synthesise their own food

Explanation:

Heterotrophs are either dependent on Phototrophs or other organisms for their food.

4. Which is the correct sequence of parts in the human alimentary canal?

(a) Mouth → stomach → small intestine → oesophagus → large intestine

(b) Mouth →oesophagus → stomach → large intestine → small intestine

(c) Mouth → stomach → oesophagus → small intestine → large intestine

(d) Mouth → oesophagus → stomach → small intestine → large intestine

Soln:

The answer is (d) Mouth → oesophagus → stomach → small intestine → large intestine

5. If salivary amylase is lacking in the saliva, which of the following events in the mouth cavity will be affected?

(a) Proteins breaking down into amino acids

(b) Starch breaking down into sugars

(c) Fats breaking down into fatty acids and glycerol

(d) Absorption of vitamins

Soln:

The answer is (b) Starch breaking down into sugars

Explanation:

The Salivary Amylase enzyme present in the saliva breaks down Starch into simpler sugar and helps in digesting them. Hence the breakdown of starch will be affected if salivary amylase is lacking in the saliva.

6. The inner lining of the stomach is protected by one of the following from hydrochloric acid. Choose the correct one (a) Pepsin

(b) Mucus

(c) Salivary amylase

(d) Bile

Soln:

The answer is (b) Mucus

7. Which part of the alimentary canal receives bile from the liver?

(a) Stomach

(b) Small intestine

(c) Large intestine

(d) Oesophagus

Soln:

The answer is (b) Small intestine

Explanation:

Bile goes to the small intestine from the gall bladder through hepta pancreatic duct.

8. A few drops of iodine solution were added to rice water. The solution turned blue-black in colour. This indicates that rice water contains

(a) complex proteins

(b) simple proteins

(c) fats

(d) starch

Soln:

The answer is (d) starch

Explanation

Starch is made up of two components Amylose and Amylopectin. When we add iodine to starch-containing water Amylose reacts with iodine to form a blue colour complex. Here solution gives blue-black colour on adding Iodine which confirms the presence of starch in the rice water.

9. In which part of the alimentary canal is food finally digested?

(a) Stomach

(b) Mouth cavity

(c) Large intestine

(d) Small intestine

Soln:

The answer is (d) Small intestine

Explanation:

Although the primary digestion process is conducted in mouth and stomach most of the digestion process occurs in the small intestine and large intestine digestion process will not take place.

10. Choose the function of the pancreatic juice from the following

(a) trypsin digests proteins and lipase carbohydrates

(b) trypsin digests emulsified fats and lipase proteins

(c) trypsin and lipase digest fats

(d) trypsin digests proteins and lipase emulsified fats

Soln:

The answer is (d) trypsin digests proteins and lipase emulsified fats

Explanation:

Trypsin breaks down proteins into polypeptides and Lipase digest emulsified fat molecules into fatty acids and glycerol.

11. When air is blown from the mouth into a test-tube containing lime water, the lime water is turned milky due to the presence of

(a) oxygen

(b) carbon dioxide

(c) nitrogen

(d) water vapour

Soln:

The answer is (b) carbon dioxide

Explanation:

Carbon dioxide reacts with lime water and turns the lime water milky.

12. The correct sequence of anaerobic reactions in yeast is

Soln:

The answer is d)

Explanation:

In Yeast cytoplasm, Glucose is breakdown in anaerobic condition to produce Pyruvate which is further breakdown to Ethanol and carbon-di-oxide

13. Which of the following is most appropriate for aerobic respiration?

Soln: Answer is Option (B)

14. Which of the following statement(s) is (are) true about respiration?

(i) During inhalation, ribs move inward and diaphragm is raised

(ii) In the alveoli, exchange of gases takes place i.e., oxygen from alveolar air diffuses into blood and carbon dioxide from the blood into the alveolar air

(iii) Haemoglobin has a greater affinity for carbon dioxide than oxygen

(iv) Alveoli increase surface area for exchange of gases

(a) (i) and (iv)

(b) (ii) and (iii)

(c) (i) and (iii)

(d) (ii) and (iv)

Soln:

The answer is (d) (ii) and (iv)

Explanation:

Statement i) is wrong because ribs move outward and the diaphragm is lowered during inhalation. Similarly Option iii) is wrong because Hemoglobin has greater affinity for Oxygen than CO2.

15. Which is the correct sequence of air passage during inhalation?

(a) Nostrils →larynx →pharynx →trachea →lungs

(b) Nasal passage →trachea →pharynx →larynx →alveoli

(c) larynx →nostrils →pharynx →lungs

(d) Nostrils →pharynx →larynx →trachea →alveoli

Soln:

The answer is (d) Nostrils →pharynx →larynx →trachea→alveoli

Explanation:

Air enter respiratory system through nostrils, passes to pharynx, larynx, trachea and then to alveoli. After inhalation diaphragm and intercoastal muscles contract along with expansion of thoracic muscles which creates enough space for the air to enter into the lungs.

16. During respiration exchange of gases take place in

(a) trachea and larynx

(b) alveoli of lungs

(c) alveoli and throat

(d) throat and larynx

Soln:

The answer is (b) alveoli of lungs

Explanation:

Trachea, Larynx provide a passage for the movement of air. Gas exchange takes place in Alveoli of lungs. From alveoli, oxygen diffuses into blood and Carbon-di-oxide exhaled out of blood.

17. Which of the following statement (s) is (are) true about the heart?

(i) The left atrium receives oxygenated blood from different parts of the body while the right atrium receives deoxygenated blood from lungs

(ii) Left ventricle pumps oxygenated blood to different body parts while right ventricle pumps deoxygenated blood to lungs

(iii) Left atrium transfers oxygenated blood to the right ventricle which sends it to different body parts

(iv) The right atrium receives deoxygenated blood from different parts of the body while the left ventricle pumps oxygenated blood to different parts of the body

(a) (i)

(b) (ii)

(c) (ii) and (iv)

(d) (i) and (iii)

Soln:

The answer is (c) (ii) and (iv)

Explanation:

Oxygenated blood circulates through the left part of the heart whereas deoxygenated blood circulates through the right part of the heart. Atrium receives blood and ventricle pumps the blood out of the heart.

18. What prevents backflow of blood inside the heart during contraction?

(a) Valves in heart

(b) Thick muscular walls of ventricles

(c) Thin walls of atria

(d) All of the above

Soln:

The answer is (a) Valves in the heart

Explanation:

Walls in the heart are responsible for only pumping of the blood and they are not responsible for blocking backflow of blood inside the heart during contraction.

19. Single circulation i.e., blood flows through the heart only once during one cycle of passage through the body, is exhibited by

(a) Labeo, Chameleon, Salamander

(b) Hippocampus, Exocoetus, Anabas

(c) Hyla, Rana, Draco

(d) Whale, Dolphin, Turtle

Soln:

The answer is (b) Hippocampus, Exocoetus, Anabas

Explanation:

In Option a) Chameleon is a reptile and Salamander is an amphibian which has 3 chambered hearts and shows partial double circulation. In Option c) all are Amphibians and they show partial double circulation. In option d) Whale is a mammal, but a turtle is a reptile hence option d) is wrong.

20. In which of the following vertebrate group/groups, the heart does not pump oxygenated blood to different parts of the body?

(a) Pisces and amphibians

(b) Amphibians and reptiles

(c) Amphibians only

(d) Pisces only

Soln:

The answer is (d) Pisces only

Explanation:

This is because of the single circulation where deoxygenated blood from all part of the body is pumped into the heart. From the heart, it is pumped to gills where it gets oxygenated and gets transferred to all parts of the body. Hence it proves Pisces will not receive oxygenated blood.

21. Choose the correct statement that describes arteries.

(a) They have thick elastic walls, blood flows under high pressure; collect blood from different organs and bring it back to the heart

(b) They have thin walls with valves inside, blood flows under low pressure and carries blood away from the heart to various organs of the body

(c) They have thick elastic walls, blood flows under low pressure; carry blood from the heart to various organs of the body

(d) They have thick elastic walls without valves inside, blood flows under high pressure and carry blood away from the heart to different parts of the body.

Soln:

The answer is (d) They have thick elastic walls without valves inside, blood flows under high pressure and carries blood away from the heart to different parts of the body.

22. The filtration units of kidneys are called

(a) ureter

(b) urethra

(c) neurons

(d) nephrons

Soln:

The answer is (d) nephrons

Explanation:

Nephron is called as the functional unit of the kidney. It helps in removing the waste products and excess substances from our body.

23. Oxygen liberated during photosynthesis comes from

(a) water

(b) chlorophyll

(c) carbon dioxide

(d) glucose

Soln:

The answer is (a) water

Explanation:

During photosynthesis, water molecule splits to produce Oxygen and Hydrogen Ions. Oxygen is expelled out of plants and Hydrogen is used to reduce Carbon-di-oxide to produce carbohydrates.

24. The blood leaving the tissues becomes richer in

(a) carbon dioxide

(b) water

(c) haemoglobin

(d) oxygen

Soln:

The answer is (a) carbon dioxide

Explanation:

Because of respiration Carbon-di-oxide gets accumulated in tissues. Hence blood leaving the tissues becomes richer in Carbon-di-oxide.

25. Which of the following is an incorrect statement?

(a) Organisms grow with time

(b) Organisms must repair and maintain their structure

(c) Movement of molecules does not take place among cells

(d) Energy is essential for life processes

Soln:

The answer is (c) Movement of molecules does not take place among cells

Explanation:

Movement of molecule is a vital process. Movement of molecules in cells take place in active and passive modes such as Diffusion, osmosis, facilitated diffusion etc.

26. The internal (cellular) energy reserve in autotrophs is

(a) glycogen

(b) protein

(c) starch

(d) fatty acid

Soln:

The answer is (c) starch

Explanation:

Glycogen is the stored energy in animals, Plants stores energy in the form of Starch.

27. Which of the following equations is the summary of photosynthesis?

(a) 6CO2 + 12H2O → C6H12O6 + 6O2 + 6H2O

(b) 6CO2 +H2O + Sunlight→C6H12O6 + O2 + 6H2O

(c) 6CO2 + 12H2O + Chlorophyll + Sunlight→ C6H12O6 + 6O2 + 6H2O

(d) 6CO2 + 12H2O + Chlorophyll + Sunlight→ C6H12O6 + 6CO2 + 6H2O

Soln:

Answer is (c) 6CO2 + 12H2O + Chlorophyll + Sunlight→ C6H12O6 + 6O2 + 6H2O

Explanation:

Option a does not show the factors responsible for photosynthesis. Option b) is not a balanced equation. Option d) is wrong as it has CO2 in the products.

28. Choose the event that does not occur in photosynthesis

(a) Absorption of light energy by chlorophyll

(b) Reduction of carbon dioxide to carbohydrates

(c) Oxidation of carbon to carbon dioxide

(d) Conversion of light energy to chemical energy

Soln:

Answer is (c) Oxidation of carbon to carbon dioxide

29. The opening and closing of the stomatal pore depend upon

(a) oxygen

(b) temperature

(c) water in guard cells

(d) concentration of CO2 in stomata

Soln:

The answer is (c) water in guard cells

Explanation:

Opening of guard cells is facilitated by the entry of water inside guard cells. This makes the guard cell turgid. The closing of guard cells is facilitated by water coming out of guard cells. This will make the guard cells flaccid.

30. Choose the forms in which most plants absorb nitrogen

(i) Proteins

(ii) Nitrates and Nitrites

(iii) Urea

(iv) Atmospheric nitrogen

(a) (i) and (ii)

(b) (ii) and (iii)

(c) (iii) and (iv)

(d) (i) and (iv)

Soln:

The answer is (b) (ii) and (iii)

Explanation:

Plants cannot absorb atmospheric Nitrogen. They can absorb Nitrogen in the form of Nitrates, Nitrites and Urea present in the soil.

31. Which is the first enzyme to mix with food in the digestive tract?

(a) Pepsin

(b) Cellulase

(c) Amylase

(d) Trypsin

Soln:

Answer is (c) Amylase

Explanation:

Amylase is secreted in mouth and acts on the starch to convert into simpler molecules. Hence Amylase is the first enzyme to mix with food in the digestive tract.

32. Which of the following statement(s) is (are) correct?

(i) Pyruvate can be converted into ethanol and carbon dioxide by yeast

(ii) Fermentation takes place in aerobic bacteria

(iii) Fermentation takes place in mitochondria

(iv) Fermentation is a form of anaerobic respiration

(a) (i) and (iii)

(b) (ii) and (iv)

(c) (i) and (iv)

(d) (ii) and (iii)

Soln:

The answer is(c) (i) and (iv)

Explanation:

Fermentation is carried out by anaerobes in the cytoplasm. Hence option ii) and iii) are wrong.

33. Lack of oxygen in muscles often leads to cramps among cricketers. This results due to

(a) conversion of pyruvate to ethanol

(b) conversion of pyruvate to glucose

(c) non-conversion of glucose to pyruvate

(d) conversion of pyruvate to lactic acid

Soln:

The answer is (d) conversion of pyruvate to lactic acid

Explanation:

The breakdown of Pyruvate in the presence of oxygen takes place in mitochondria leading to the formation of Lactic acid. Due to workout oxygen is used for the production of energy leading to the lack of oxygen and production of lactic acid.

34. Choose the correct path of urine in our body

(a) kidney → ureter → urethra → urinary bladder

(b) kidney → urinary bladder → urethra → ureter

(c) kidney → ureters → urinary bladder → urethra

(d) urinary bladder → kidney → ureter → urethra

Soln:

Answer is (c) kidney → ureters → urinary bladder → urethra

Explanation:

Urine from nephron is brought to the collecting duct of kidneys where the urine enters the ureters. There are 2 ureters, each opening from one kidney into the urinary bladder. The urinary bladder stores urine and its size increases as the amount of urine collected increases. When the CNS gives a voluntary message the muscles of bladder contract and the bladder sphincter relaxes thus excreting urine out through the urethra.

35. During deficiency of oxygen in tissues of human beings, pyruvic acid is converted into lactic acid in the

(a) cytoplasm

(b) chloroplast

(c) mitochondria

(d) Golgi body

Soln:

Answer is (a) cytoplasm

Explanation:

When there is lack of oxygen Breakdown of Pyruvate takes place in the cytoplasm of muscle cells leading to the formation of Lactic acid.

Short Answer Questions

36. Name the following

(a) The process in plants that links light energy with chemical energy

(b) Organisms that can prepare their own food

(c) The cell organelle where photosynthesis occurs

(d) Cells that surround a stomatal pore

(e) Organisms that cannot prepare their own food

(f) An enzyme secreted from gastric glands in the stomach that acts on proteins.

Soln:

1. Photosynthesis
2. Autotrophs
3. Chloroplasts
4. Guard cells
5. Heterotrophs
6. Pepsin

37. “All plants give out oxygen during day and carbon dioxide during the night”. Do you agree with this statement? Give reason.

Soln:

The statement is wrong because plants respire every time and expel out Carbon-di-oxide every time but they give out oxygen only in the daytime as the photosynthesis process can take place only in the presence of sunlight.

38. How do the guard cells regulate the opening and closing of stomatal pores?

Soln:

Opening of guard cells is facilitated by the entry of water inside guard cells. This make the guard cell turgid. The closing of guard cells is facilitated by water coming out of guard cells. This will make the guard cells flaccid.

Entry of water inside guard cells will make the cell turgid leading to the opening of stomata. Similarly, the cell becomes flaccid when water comes out of guard cells, this leads to the closing of the stomata.

39. Two green plants are kept separately in oxygen-free containers, one in the dark and the other in continuous light. Which one will live longer? Give reasons.

Soln:

The plant kept in continuous light live longer because plants release CO2 during respiration. In the case of the plant kept in the dark, CO2 resulting in lack of oxygen and the plant will die earlier.

40. If a plant is releasing carbon dioxide and taking in oxygen during the day, does it mean that there is no photosynthesis occurring? Justify your answer.

Soln:

If a plant is releasing carbon dioxide and taking in oxygen during the day means plant is respiring; it does not mean that there is no photosynthesis occurring in the plant. This is because Photosynthesis and respiration are two independent processes.

41. Why do fishes die when taken out of water?

Soln:

Fishes can respire only by using dissolved oxygen. When we take fish out of the water it cannot respire due to lack of dissolved oxygen and they die.