NCERT Exemplar Class 10 Science Solutions Chapter 6 Life Processes

According to CBSE Syllabus 2025-26, this chapter has been renumbered as Chapter 5.

NCERT Exemplar Class 10 Science Solutions Chapter 5: The chapter covers fundamental biological processes such as nutrition, respiration, digestion, excretion and transportation. Students can refer to Science Class 10 chapter 5 MCQ to strengthen their conceptual understanding and problem-solving skills. Moreover, solving these important questions helps students revise key topics and gain confidence before the exam. The NCERT exemplar solutions provide a variety of objective-type questions and their answers to test the application of concepts in real-life scenarios.

For a structured approach, students can use a Life Process Class 10 PDF which contains well-explained solutions to exemplar problems. Practising the MCQs regularly enhances analytical thinking and accuracy exams by consistently working through these resources. Students can ensure a strong understanding of chapter 5, and improve their overall science scores. These exemplar solutions give an extra edge to the students while attempting the problems given in the NCERT Class 10 Science Book.

Life Process Class 10 Chapter 5 Exemplar MCQs

Question:1

Which of the following statements about the 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 tropic level in the food chain s

Answer:C

Autotrophs can convert CO2 and H2O into carbohydrates only in the presence of sunlight. Autotrophs have chlorophyll which takesunlightnd breaks water into hydrogen and oxygen and converts CO2 into carbohydrates but this happens only in the presence of sunlight.

So statement (c) is incorrect and thus it is the right answer.

Question: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

Answer: (b)

Yeast, mushroom and bread mould are saprophytes. They break down and convert complex organic molecules present in dead and decaying matter into simpler substances outside their body. These simpler substances are then absorbed by them. This is known as saprotrophic nutrition.

Hence option (b) is correct.

Question:3

Select the correct statement
(a) Heterotrophs do not synthesise their food
(b) Heterotrophs utilise solar energy for photosynthesis
(c) Heterotrophs synthesise their food
(d) Heterotrophs are capable of converting carbon dioxide and water into carbohydrates

Answer:(a)

Heterotrophs are those organisms which cannot make their food from inorganic substances like CO2 and water. They depend on autotrophs.

Hence only statement (a) is correct.

Question:4

Which is the correct sequence of particles in the human alimentary canal?
(a) Mouth $\to$ stomach $\to$ small intestine $\to$ oesophagus $\to$ large intestine
(b) Mouth $\to$ oesophagus $\to$ stomach $\to$ large intestine $\to$ small intestine
(c) Mouth $\to$ stomach $\to$ oesophagus $\to$ small intestine $\to$ large intestine
(d) Mouth $\to$ oesophagus $\to$ stomach $\to$ small intestine $\to$ large intestine

Answer:(d)

The food enters through the mouth then passes to the stomach via Oesophagus then to the small intestine and then to the large intestine.

Hence, the correct sequence of the main parts of the alimentary canal is:

• The Mouth and Oral cavity.

• Oesophagus.

• Stomach.

• Small intestine.

• Large intestine.

Hence option (d) is correct.

Question: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

Answer:(b)

Salivary amylase is an enzyme which breaks down starch present in the food in the mouth. If this is absent, it will affect the breakdown of starch.

Protein breaks down to amino acids by protease.

Fat breaks down in the small intestine by bile.

Hence option (b) is correct.

Question: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

Answer:(b)

Pepsin is a stomach enzyme that serves to digest proteins found in ingested food.

Mucus is present in the gastric juice which is secreted by the glands present in the stomach wall. It helps to protect the stomach lining from Hydrochloric acid secreted by it.

Salivary amylase is an enzyme which breaks down starch present in the food in the mouth.

Fat breaks down in the small intestine by bile.

Hence option (b) is correct.

Question:7

Which part of the alimentary canal receives bile from the liver?
(a) Stomach
(b) Small intestine
(c) Large intestine
(d) Oesophagus

Answer: (b)

Bile is a liquid that is made and delivered by the liver and put away in the gallbladder.

The small intestine receives bile from the liver, which is normally stored in the gall bladder.

Bile assists with digestion. It separates fats into unsaturated fats, which can be taken into the body by the stomach.

Question:8

A few drops of iodine solution were added to rice water. The solution turned blue-black. This indicates that rice water contains
(a) complex proteins
(b) simple proteins
(c) fats
(d) starch

Answer:(d)

Starch solution with the addition of iodine turns blue-black and this test is used as a conformation test for iodine.

The iodine–starch test is a chemical reaction that is used to test for the presence of starch or iodine. The combination of starch and iodine is intensely blue-black.

Question:9

In which part of the alimentary canal food is finally digested?
(a) Stomach
(b) Mouth cavity
(c) Large intestine
(d) Small intestine

Answer:(d)

The food is finally digested in the small intestine due to microvilli which increase the surface area and have lot of blood vessels which absorb food and deliver it to all the other parts of the body.

The muscles of the small intestine tract blend food in with stomach-related juices from the pancreas, liver, and digestive system, and push the combination forward for additional absorption.

The walls of the small intestine retain water and the processed supplements into your circulatory system. The waste products of the digestive process move into the large intestine.

Question: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

Answer: (d)

The pancreas secretes pancreatic juice which contains:

Amylase

Lipase

Trypsin

The function of each enzyme:

• Amylase breaks down starch

• Lipase breaks emulsified fats

• Trypsin digests proteins

Hence option (d) is correct.

Question:11

When air is blown from the the m mouth into a test tube containing lime water, the lime water turns red milky due to the presence of
(oxygen
(b) carbon dioxide
(c) nitrogen
(d) water vapour

Answer:(b)

Carbon dioxide turns lime water milky and this is a conformation test for the presence of Carbon dioxide.

Hence option (b) is correct.

Question:12

The correct sequence of anaerobic reactions in yeast is
(a) Glucose $\stackrel{cytoplasm}{\to }$ Pyruvate $\stackrel{mitochondria}{\to }$ Ethanol + Carbon dioxide
(b) Glucose $\stackrel{cytoplasm}{\to }$ Pyruvate $\stackrel{cytoplasm}{\to }$ Lactic acid
(c) Glucose $\stackrel{cytoplasm}{\to }$ Pyruvate $\stackrel{mitochondria}{\to }$ Lactic acid
(d) Glucose $\stackrel{cytoplasm}{\to }$ Pyruvate $\stackrel{cytoplasm}{\to }$ Ethanol + Carbon dioxide

Answer:(d)

Anaerobic respiration occurs in the absence of oxygen. It is carried out by yeast and some bacteria.

Glucose breaks down into pyruvate in the absence of oxygen. The reaction is as follows:

Glucose $\stackrel{cytoplasm}{\to }$ Pyruvate $\stackrel{cytoplasm}{\to }$ Ethanol + Carbon dioxide

Glucose breaks down into ethanol, carbon dioxide

Question:13

Which of the following is most appropriate for aerobic respiration?
(a) Glucose $\stackrel{mitochondria}{\to }$ Pyruvate $\stackrel{cytoplasm}{\to }$ $C{O}_2+H_{2}O+Energy$
(b) Glucose $\stackrel{cytoplasm}{\to }$ Pyruvate $\stackrel{mitochondria}{\to }$ $C{O}_2+H_{2}O+Energy$
(c) Glucose $\stackrel{cytoplasm}{\to }$ Pyruvate + Energy $\stackrel{mitochondria}{\to }$ $C{O}_2+H_{2}O$
(d) Glucose $\stackrel{cytoplasm}{\to }$ Pyruvate + Energy $\stackrel{mitochondria}{\to }$ $C{O}_2+H_{2}O+Energy$

Answer: (b)

Aerobic respiration uses oxygen for respiration. It takes place in the mitochondria. After glycolysis, pyruvate (from the cytoplasm) enters mitochondria and is oxidized in serreactionsctions to form $CO_{andand{and ATP. The reaction is as follows:

Glucose $\stackrel{cytoplasm}{\to }$ Pyruvate $\stackrel{mitochondria}{\to }$ $C{O}_2+H_{2}O+Energy$

Question:14

Which of the following statement(s) is (are) true about respiration?
(i) During inhalation, ribs move inward and the diaphragm is raised
(ii) In the alveoli, an exchange of gases takes place i.e., oxygen from alveolar air diffuses into the 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)

Answer:(d)

During inhalation, the diaphragm pulls downward which induces the lower ribs to move upward and forward. Hence the given statement is false. The alveoli are the place where the lungs and the blood trade oxygen and carbon dioxide on the way toward breathing in and breathing out. In the alveoli, exchange of gases takes place i.e., oxygen from alveolar air diffuses into blood and carbon dioxide from blood into alveolar air. This statement is true.

Oxygen ties to the iron particles in the haemoglobin while carbon dioxide $C{O}_2$ is bound to the haemoglobin chains of the structure. Hence haemoglobin has a greater affinity for oxygen than carbon dioxide. Hence the given statement is false. Many alveoli are present in the lungs with a shape that further increases surface area for exchange of gases. This statement is true.

Hence option (d) is correct.

Question:15

Which is the correct sequence of air passage during inhalation?
(a) Nostrils $\to$ larynx $\to$ pharynx $\to$ trachea $\to$ lungs
(b) Nasal passage $\to$ trachea $\to$ pharynx $\to$ larynx $\to$ alveoli
(c) larynx $\to$ nostrils $\to$ pharynx $\to$ lungs
(d) Nostrils $\to$ pharynx $\to$ larynx $\to$ trachea $\to$ alveoli

Answer:(d)

Air is drawn into our body through the nostrils, then it goes into the nasal passage from there it enters the pharynx then to larynx to the trachea to finally alveoli where the final oxygen and carbon dioxide are exchanged.

So the correct passage is: Nostrils ⇒ pharynx ⇒ larynx ⇒ trachea ⇒ alveoli

Hence option (d) is correct.

Question:16

During respiration exchange takes cases takes place in
(a) trachea and larynx
(b) alveoli of lungs
(c) alveoli and throat
(d) throat and larynx

Answer:(b)

The alveoli is the place where the exchange of carbon dioxide and oxygen takes place.

Air is drawn into our body through the nostrils, then it goes into the nasal passage. From there it enters the pharynx and the hen to the ynx to the trachea finally alveoli where the final oxygen and carbon dioxide are exchanged.

Hence option (b) is correct.

Question:17

Which of the following statement (s) is (are) true about the heart?
(The i) The left atrium receives oxygenated blood from different parts of the body while the right atrium receives deoxygenated blood from the lungs
(ii) The left ventricle pumps oxygenated blood to different body parts while the right ventricle pumps deoxygenated blood to the lungs
(iii) The 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)

Ans.(c)

The right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle.

The right ventricle pumps the oxygen-poor blood to the lungs through the pulmonary valve.

The left atrium receives oxygen-rich blood from the lungs and pumps it to the left ventricle through the mitral valve.

The left ventricle pumps the oxygen-rich blood through the aortic valve out to the rest of the body.

Hence option (c) is correct.

Question:18

What prevents backflow the flow of blood inside the heart during contraction?
(a) Valves in the heart
(b) Thick muscular walls of ventricles
(c) Thin walls of atria
(d) All of the above

Answer:(a)

Valves ensure there is no backflow of blood inside the heart during contraction they close and separate oxygenated and deoxygenated blood from mixing.

Thick muscular walls of ventricles have to pump blood out of the heart.

Thin walls of the atria carry the blood towards the heart.

Hence option (a) is correct.

Question: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

Answer:(b)

Animal group Heart Examples

Amphibians and Reptiles 3-chambered heart Salamander, Hyla,

(two atria and one ventricle) Rana (Amphibians)

Chameleon,

Draco, Turtle

Fishes 2-chambered heart Hippocampus,

(one atrium and Labeo, Anabas,

one ventricle) Exocoetus etc.

Birds and mammals 4-chambered heart Pigeon, parrot,

(two atria and whale, dolphins,ventriclesricle) humans

Question:20

In which of the following vertebrate groups/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

Answer:(d)

Fishes have a single closed circulatory system. In this, blood is contained inside blood vessels and circulates in a single direction. Blood flows from the heart around the systemic circulatory route, and then returns to the heart again.

Fishes have a two-chambered heart that has only one atrium and one ventricle. The atrium gathers blood that has gotten back from the body and the ventricle pumps the blood to the gills where gas exchange takes place and the blood is re-oxygenated; this is called gill circulation or gill flow.

The blood at that point proceeds through the remainder of the body before showing up back at the atrium; this is called systemic circulation. This unidirectional progression of blood delivers a slope of oxygenated to deoxygenated blood around the fish's fundamental circuit. The outcome is a breaking point in the measure of oxygen that can arrive at some of the organs and tissues of the body, reducing the overall metabolic capacity of fish.

So the answer is option (d), Pisces only.

Question: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; and 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 carries blood away from the heart to different parts of the body.

Answer: (d)

Arteries are the vessels which carry blood away from the heart to various organs of the body. As the blood flows away from the heart with very high pressure, arteries have thick walls.

Hence option (d) is correct.

Question:22

The filtration units of kidneys are called
(a) ureter
(b) urethra
(c) neurons
(d) nephrons

Answer:.(d)

Nephrons are the structural unit of kidneys. It is the structural unit of a kidney.

A nephron is utilized to separate water, particles and little atoms from the blood, filter through wastes and poisons, and return required particles to the blood.

Hence option (d) is correct.

Question:23

Oxygen liberated during photosynthesis comes from
(a) water
(b) chlorophyll
(c) carbon dioxide
(d) glucose

Answer:

Photosynthesis is the process by which green plants and certain other organisms transform light energy into chemical energy.

Chlorophyll absorbs ultraviolet and breaks molecules molecule and forms oxygen. So, we get oxygen from the water molecule.

$6C{O}_2+6H_{2}O\to C_6{H}_{12}{O}_6+6O_2$

Question:24

The blood leaving the tissues becomes richer in
(a) carbon dioxide
(b) water
(c) haemoglobin
Oxygenygen

Answer:

Blood leaving the tissue is enriched with carbon dioxide. The aorta carries oxygenated blood from the heart to the organs. When this blood passes through the capillaries of body organs, it gives oxygen to the body cells.

Hence the blood which reaches the tissue is enriched with oxygen which is absorbed by the tissue and the carbon dioxide from the cell is exchanged for oxygen.

Deoxygenated blood (carrying $C{O}_2$) leaves the tissues anthe d enters the vena cava, from where they are again passed to the lungs for

oxygenation.

Hence option (a) is correct.

Question: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

Answer:

Organisms grow with time - true

Organisms must repair and maintain their structure – If they do not do so, they will no longer be alive. Hence the statement is true.

Molecules move from one cell to another, for example, oxygen and food move from cell to cell. Hence the statement is false.

Energy is needed to carry out life processes, such as breaking down and building up molecules, transporting many molecules

across cell membranes etc. Hence the statement is true.

Hence option (c) is correct.

Question:26

The internal (cellular) energy reserve in autotrophs is
(a) glycogen
(b) protein
(c) starch
(d) fatty acid

An answer: C

Autotrophs comprise green plants that photosynthesize their food. In autotrophs, the energy reserve is stored in the form of staheterotrophseterotrophs, and food is stored in the form of glycogen.

Hence option (c) is correct.

Question:27

Which of the following equations is the summary of photosynthesis?
(a) $6C{O}_2+12H_{2}O\to C_6{H}_{12}{O}_6+6O_2+6H_{2}O$
(b) $6C{O}_2+H_{2}O+Sunlight\to C_6{H}_{12}{O}_6+O_2+6H_{2}O$
(c) $6C{O}_2+12H_{2}O+Chlorophyll+Sunlight\to C_6{H}_{12}{O}_6+6O_2+6H_{2}O$
(d) $6C{O}_2+12H_{2}O+Chlorophyll+Sunlight\to C_6{H}_{12}{O}_6+6C{O}_2+6H_{2}O$

Answer: (c)

Photosynthesis is a multi-step process that requires sunlight, carbon dioxide, and water as substrates.

Summary of Photosynthesis in equation form

$6C{O}_2+12H_{2}O+Chlorophyll+Sunlight\to C_6{H}_{12}{O}_6+6O_2+6H_{2}O$

Question: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

Answer: (c)

Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. Carbon dioxide is used in photosynthesis for the production of food.

Summary of Photosynthesis in equation form

$6C{O}_2+12H_{2}O+Chlorophyll+Sunlight-\to C_{6}H12O_6+6O_2+6H_{2}O$

Absorption of light energy by chlorophyll takes place. Carbon dioxide is reduced and fixed in the form of carbohydrates. Reduction of carbon dioxide to carbohydrates also takes place. Oxygen is released from the water molecules. Oxidation of carbon to carbon dioxide does not take place. Conversion of light energy to chemical energy takes place.

Hence option (c) is the correct answer.

Question:29

The opening and closing of the stomatal pore depends upon
(a) oxygen
(b) temperature
(c) water in guard cells
(d) concentration of $C{O}_2$ in stomata

Answer:

Closing and opening of guard cells depends on the water content in the cells. If there is water in the cells the pores get opened and if there is less water, the cell shrinks and the pore gets closed.

Hence option (c) is correct.

Question: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)

Answer:(b) Asian ganen is an essential element in forming proteins and it is observed in the form of nitrates, nitrites and urea. Sometimes we add urea to the soil and plants have adopted a lot to overcome nitrogen deficiency, for example, Carnivorous plants.

Hence option (b) is correct.

Question:31

Which is the first enzyme to mix with food in the digestive tract?
(a) Pepsin
(b) Cellulase
(c) Amylase
(d) Trypsin

Answer:(c)

Salivary amylase is the first enzyme which is present in the saliva which gets mixed with the food in the mouth and starts breaking the starch in the food.

• Salivary amylase breaks down starches into disaccharides

• Pepsin breaks down proteins into large peptides

• Trypsin continues the breakdown of protein

Therefore option (C) is correct

Question: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)

Answer:(c)

Fermentation is a form of anaerobic respiration. Pyruvate can be converted into ethanol and CO2 in yeast during fermentation. Since this process takes place in the absence of air (Oxygen), it is called anaerobic respiration.

It takes place in the cytoplasm.

Hence (i) and (iv) are correct

Therefore option (C) is correct

Question: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

Answer:d

• An excessively acidic condition of the body fluids is known as acidosis.

• Intracellular acidosis happens because of lactic acid accumulation and it has been viewed as the main source of skeletal muscle weariness.

• Lactic acid is produced in the muscle from the metabolism of carbohydrates in the presence of low oxygen. This causes pain and weariness in muscles.

Therefore option (D) is correct

Question:34

Choose the correct path of urine in our body
(a) kidney $\to$ ureter $\to$ urethra $\to$ urinary bladder
(b) kidney $\to$ urinary bladder $\to$ urethra $\to$ ureter
(c) kidney $\to$ ureters $\to$ urinary bladder $\to$ urethra
(d) urinary bladder $\to$ kidney $\to$ ureter $\to$ urethra

Answer: C

The urine formed in each kidney eventually enters a long tube that uretconnectsnectthe the kidney with the urinary bladder. Urine is stored in the urinary bladder which passes out through the urethra.

The urinary tract pathway includes:

• Kidneys: They filter waste from the blood and produce urine

• Ureters: Two thin tubes responsible for urine transfer from the kidney to the bladder

• Bladder: A sac that holds the urine

• Urethra: Tube that carries urine from the bladder out of the body

Therefore option (C) is correct

Question: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

Answer:

The pyruvate formed from glycolysis goes into Kreb's cycle as an acetyl co-enzyme and creates a pool of chemical energy (ATP, NADH and FADH2). One of the substitute destinies of pyruvic acid in cellular respiration is that it can be changed over into lactic acid. This regularly happens in the cytoplasm of solid tissue under exhausting conditions. Hence Pyruvic acid is converted into lactic acid in the cytoplasm of muscle cells during deficiency of oxygen in human beings.

Therefore option (A) is correct

NCERT Exemplar Class 10 Science Solutions Chapter 5-Short Answer

Question:36

Name the following
(a) The process in plants that links light energy with chemical energy
(b) Organisms that can prepare their food
(c) The cell organelle where photosynthesis occurs
(d) Cells that surround a stomatal pore
(e) Organisms that cannot prepare their food
(f) An enzyme secreted from gastric glands in the stomach that acts on proteins.

Answer:

a) Photosynthesis: the process using which green plants transform light energy into chemical energy

b) Autotrophs: The organisms which can prepare their food

c) Chloroplast: Cell organelle where photosynthesis takes place. It contains chlorophyll which is the enzyme responsible for the conversion of light energy into chemical energy

d) Guard cells: Organelles that surround the stomatal pore. This cell controls the opening and closing of the stomatal pore

e) Heterotrophs: The organisms which cannot prepare their food and depend on other organisms for their nutritional needs

f) Pepsin: The enzyme which is secreted by the gastric glands in the stomach that acts on proteins

Question:37

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

Answer:

“All plants give out oxygen during the day and carbon dioxide during the night”

The above statement is correct. All plants produce oxygen during day time as photosynthesis takes place in the presence of sunlight and oxygen is a byproduct of photosynthesis. At night time, photosynthesis takes place place and the normal cellular respiration of plants releases carbon dioxide.

Question:38

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

Answer:

Guard cells regulate the opening and closing of the stomatal pores by swelling and shrinking normally. Guard cells will swell by absorbing water and opening the pores and by shrinking the guard cells will close the pores. When guard cells are turgid, the stomatal pore is open while in flaccid conditions, the stomatal aperture closes.

Question: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.

Answer:

The plant placed in the dark will die as it cannot perform photosynthesis and within a few times, the whole chamber will be filled with carbon dioxide. On the other hand, the plant in the open sunlight will perform photosynthesis (and produce oxygen required for its respiration) and this plant lives for a longer duration.

Question: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.

Answer:

Photosynthesis and respiration are two independent processes.

• Respiration: Process of oxidation of food substances. It releases carbon dioxide and takes place throughout the day.

• Photosynthesis: Process of fixing the atmospheric carbon dioxide into organic compounds (carbohydrates). It releases oxygen gas as a by-product.

Photosynthesis takes place in the presence of Sunlight only. If a plant is releasing carbon dioxide and taking in oxygen during the day, it does not mean that there is no photosynthesis occurring. It means that the rate of photosynthesis is slow.

Question:41

Why do fishes die when taken out of water?

Answer:

Respiration in fishes takes place using gills.

Gills can only absorb oxygen which is dissolved in water and cannot take oxygen which is present in the atmosphere. At the point when the water enters the fish through its mouth, the oxygen is taken inside and carbon dioxide is given out through the gills.

So when the fish is taken out of water, the supply of oxygen is cut down and they cannot breathe for long. That's the reason fishes die when we take them out of water.

Question:42

Differentiate between an autotroph and a heterotroph.

Answer:

Autotrophs Heterotrophs

1. Can prepare their food 1. Heterotrophs depend on

with the help of sunlight, air, and water autotrophs and other organisms for

nutrition.

2. Autotrophs are the primary producers 2. Heterotrophs are the consumers

3. They are placed first in the food chain 3. They are placed at secondary and tertiary levels.

4. Examples: Plants, algae and 4. Examples: Animals like cows, dogs, a

few bacteria lions, horses, etc.

Question:43

Is ‘nutrition’ a necessity for an organism? Discuss.

Answer:

Yes, all living organisms need nutrition as it provides the energy required for all the metabolic processes in a living organism.

Nutrition is needed:

(a) For metabolic processes in the body, it serves as an energy source

(b) Repair and maintain the existing cells and support the growth of new cells.

(c) To give opposition against various diseases.

Question:44

What would happen if green plants disappear from the earth?

Answer:

Green plants are predominant autotrophs which provide food for all the heterotrophs on this planet. These organisms occupy the first trophic level in the food chain and serve as a source of food and energy for all other organisms of higher trophic levels (heterotrophs). They also balance the carbon dioxide and oxygen levels in the atmosphere so if green plants disappear then the life on this planet will cease to exist.

Question:45

Leaves of a healthy potted plant were coated with Vaseline. Will this plant remain healthy for long? Give reasons for your answer.

Answer:

When the leaves of a healthy plant are coated with Vaseline it will block the stomatal pores. This will not allow the oxygen and carbon dioxide exchange so the plant will not live healthy for a long time. Plants will not be able to take in oxygen for respiration and carbon dioxide for photosynthesis.

Question:46

How does aerobic respiration differ from anaerobic respiration?

Answer:

Question:47

Match the words of Column (A) with that of Column (B)
Column (A) Column (B)
(a) Phloem (i) Excretion
(b) Nephron (ii) Translocation of food
(c) Veins (iii) Clotting of blood
(d) Platelets (iv) Deoxygenated blood

Answer:

(a) Phloem: Translocation of food

(b) Nephron: Excretion

(c) Veins: Deoxygenated blood

(d) Platelets: Clotting of blood

Question:48

Differentiate between an artery and a vein.

Answer:

Question:49

What are the adaptations of leaves for photosynthesis?

Answer:

Adaptation of leaves:

1. Large surface area for the maximum absorption of light.

2. The presence of numerous stomatal pores for carbon dioxide and oxygen exchange.

3. Presence of chlorophyll to absorb light and make photosynthesis possible.

4. An extensive network of veins transports substances to and fro quickly from mesophyll cells.

Question:50

Why is the small intestine in herbivores longer than in carnivores?

Answer:

Herbivores get their nourishment from plants which thus makes cellulose the main component of their diet Herbivorous animals which eat grass need longerintestiness to absorb the cellulose in the food whereas meat-eating animals can digest as there is no cellulose to digest.

Cellulose digestion is a long process and is done by intestinal ruminant bacteria present ithe n the gut of herbivores.

Question:51

What will happen if mucus is not secreted by the gastric glands?

Answer:

Gastric juice is produced by the gastric glands of the stomach. It contains pepsinogen, HCl, and mucus. HCl imparts highly acidic pH to the stomach which thus bolsters the transformation of idle pepsinogen into dynamic pepsin.

The mucus protects the inner lining of the stomach from the HCl produced by gastric glands. If mucus is not released it will lead to damage to the inner lining of the stomach causing acidity and ulcers.

Question:52

What is the significance of the emulsification of fats?

Answer:

Emulsification refers to the breakdown of fat globules in the duodenum into tiny droplets. This provides a larger surface area on which the enzyme pancreatic lipase can act to digest the fats into fatty acids and glycerol. Hence, it facilitates the digestion of fats.

Question:53

What causes the movement of food inside the alimentary canal?

Answer:

Peristalsis causes the movement of food inside the alimentary canal.

It is the rhythmic contraction and relaxation of muscles which pushes the food forward in the alimentary canal.

Question:54

Why does absorption of digested food occur mainly in the small intestine?

Answer:

Digestion of food takes place in the small intestine because it has small projections on the surface called villi which increases the surface area. The small intestine is richly supplied with blood vessels which take the absorbed food to all the cells of the body.

Question:55

Match Group (A) with Group (B)
Group (A) Group (B)
(a) Autotrophic nutrition (i) Leech
(b) Heterotrophic nutrition (ii) Paramecium
(c) Parasitic nutrition (iii) Deer
(d) Digestion in food vacuoles (iv) Green plant

Answer:

Autotropic Nutrition: Consists of the organisms which make their food. For example, plants. These organisms are known as autotrophs.

Heterotopic Nutrition: Consists of the organisms which depend on autotrophs for nutrition. For example, deer. These organisms are known as heterotrophs.

Parasitic nutrition: Consists of the organisms that feed on a living host for nutrition. For example, leech. These organisms are known as parasites.

Digestion of food in vacuoles is a mode of digestion which is prominent in microorganisms. Example, Paramecium.

Question:56

Why is the rate of breathing in aquatic organisms much faster than in terrestrial organisms?

Answer:

Fishes absorb dissolved oxygen from water through gills. As the amount of dissolved oxygen in water is low and to compensate for that low oxygen, the organism has a faster breathing rate as compared to that of terrestrial organisms.

Question:57

Why is blood circulation in the human heart called double circulation?

Answer:

In humans, blood passes through the heart twice during one complete cardiac cycle of the body. Once through the right ventricle to the left auricle of the heart, called pulmonary circulation. Second through the left ventricle to right auricle of the heart through body tissues, called systemic circulation.

Advantages of double circulation:

• Maintains higher blood pressure

• Allows greater flow of blood to the tissues.

• Creates more pressure to pump blood to other organs.

• Produces a large amount of energy to maintain life processes.

Question:58

What is the advantage of having a chambered heart?

Answer:

The four chambers of the heart are as follows:

Advantages of four-chambered heart:

1) A chambered heart ensures the separation of oxygenated and deoxygenated blood

2) Highly efficient in supplying oxygenated blood to all parts of the body

3) This is prominent in warm blood animals which have high energy needs.

4) Maintains higher blood pressure and allows greater flow of blood to the tissue

Question:59

Mention the major events during photosynthesis

Answer:

Photosynthesis is the process by which green plants and certain other organisms transform light energy into chemical energy.

It is a multi-step process that requires sunlight, carbon dioxide, and water as substrates.

Summary of Photosynthesis in equation form

$6C{O}_2+12H_{2}O+Chlorophyll+Sunlight\to C_6{H}_{12}{O}_6+6O_2+6H_{2}O$

Major Events of Photosynthesis are as follows:

1) Absorption of sunlight by chlorophyll

2) Transfer of electrons

3) Generation of ATP: Conversion of light energy into chemical energy and splitting of water molecules into hydrogen and oxygen.

4) Carbon fixation: Reduction of Carbon dioxide to carbohydrates.

Question:60

In each of the following, what happens to the rate of photosynthesis?
(a) Cloudy days
(b) No rainfall in the area
(c) Good manuring in the area
(d) Stomata get blocked due to dust

Answer:

Photosynthesis is the process by which green plants and certain other organisms transform light energy into chemical energy.

It is a multi-step process that requires sunlight, carbon dioxide, and water as substrates.

Summary of Photosynthesis in equation form

$6C{O}_2+12H_{2}O+Chlorophyll+Sunlight\to C_6{H}_{12}{O}_6+6O_2+6H_{2}O$

(a) Cloudy days: The rate of photosynthesis decreases as the sunlight is low.

As the intensity of light decreases, the rate of light-dependent reactions of photosynthesis and in turn, the rate of

photosynthesis decreases.

(b) No rainfall in the area: The rate of photosynthesis decreases as the water is needed for photosynthesisWhichch gets broken into oxygen and hydrogen which later converts into carbohydrates.

(c) Good Manuring in the area: The rate of photosynthesis increases as plants need raw minerals such as Fe, N, Mg, P….etc. fForbuilding their body and manuring increases raw minerals which further increases the rate of photosynthesis.

(d)$C{O}_2$ gas enters the leaves through stomata. If stomata get blocked due to dust, $C{O}_2$ gets blocked and hence the rate of photosynthesis decreases.

Question:61

Name the energy currency in the living organisms. When and where is it produced?

Answer:

The energy currency of living organisms is ATP (Adenosine triphosphate).

It is produced in mitochondria at the end of respiration where ADP (Adenosine diphosphate) is converted to ATP (Adenosine triphosphate).

Question:62

What is common for cuscuta, ticks and leeches?

Answer:

Cuscuta ticks and leeches all are parasites witthehparasiticic modes of nutrition where the organism absorbs food from the host without giving any benefit to the host. Parasites are harmful host organisms.

Question:63

Explain the role othethe f the mouth in the digestion of food.

Answer:

Role of mouth in the digestion of food

1) Teeth cut the food and increase the surface area of food to absorb enzymes.

2) The salivary glands mother secret saliva which contains an enzyme called salivary amylase which digests the starch present in the food (chemical digestion)

3) Tongue helps in the tough mixing of food with saliva

Question:65

Match the terms in Column (A) with those in Column (B)
Column (A) Column (B)
(a) Trypsin (i) Pancreas
(b) Amylase (ii) Liver
(c) Bile (iii) Gastric glands
(d) Pepsin (iv) Saliva

Answer:

Trypsin is secreted by the pancreas which helps in digesting proteins.

Salivary amylase is present in saliva which helps in digesting starch in food.

Bile is secreted by the liver which contains lipase which helps in the emulsification of fats.

Pepsin is secreted by gastric glands which helps in protein digestion.

Question:66

Name the correct substrates for the following enzymes
(a) Trypsin
(b) Amylase
(c) Pepsin
(d) Lipase

Answer:

Trypsin is secreted by the pancreas which helps in digesting proteins.

Salivary amylase is present in saliva which helps in digesting starch in food.

Pepsin is secreted by gastric glands which helps in protein digestion.

Bile is secreted by the liver which contains lipase which helps in the emulsification of fats.

Question:67

Why do veins have thin walls as compared to arteries?

Answer:

Blood emerges from the heart with high pressure. Arteries are thick-walled because they are responsible for carrying high-pressure blood to other body organs.

Compared to arteries, veins carry deoxygenated blood from all body parts back to the heart. The blood flowing is not under high pressure therefore veins are thin-walled blood vessels.

Question:68

What would happen if platelets were absent in the blood?

Answer: The main objective of platelets is to form a blood clot in case of an injury. In the absence of platelets, the process of clotting will not take place which will lead to blood loss. Excessive loss of blood might be fatal in many cases.

Question:69

Plants have low energy needs as compared to animals. Explain.

Answer:

All the movements in plants are cellular. Plants do not move physically as humans or animals. Sclerenchyma is the tissue which makes the plant hard and stiff. It is known as a supporting tissue. They provide strength to the plant making energy requirements low for the plant.

On the other hand, animals require more energy because they need to move from one place to another for food, shelter, mating etc.

Question:70

Why and how does water enter continuously into the root xylem?

Answer:

Water is required by plants for photosynthesis. Transpiration is the process of water movement through a plant and its evaporation.

Transpiration pull makes the water enter continuously into the root xylem. The water is lost to the atmosphere by the stomata. This water is pulled from the xylem to the roots to the leaves.

Cells of roots are in close contact with soil and thus effectively take up particles by dispersion. Tion concentration increments inside the root and henceforth osmotic pressure expands the development of water from the soil into the root which happens constantly.

Question:71

Why is transpiration important for plants?

Answer:

Transpiration is the process of water movement through a plant and its evaporation.

1. It helps in absorption. of water

2. It helps in the upward movement of water and minerals from the root system to the shoot system.
   It helps in thermoregulation, i.e., maintaining the internal temperature of the plant therefore preventing it from heating up.

Question:72

How do leaves of plants help in excretion?

Answer:

1) Stomata are the tiny openings present on the epidermis of leaves. Gaseous waste of respiration and photosynthesis are removed through stomata.

2) In many plants, waste material is stored in the vacuoles of mesophyll cells and epidermal cells. This waste is excreted along with the older leaves when they fall.

NCERT Exemplar Class 10 Science Solutions Chapter 5-Long Answer

Question:73

Explain the process of nutrition in Amoeba.
Answer:

The process of obtaining food by amoeba is called phagocytosis. Various steps of involved phagocytosis in Amoeba are as follows:

1. Ingestion: Food ingests particles by forming temporary finger-like structures called pseudopodia. Food is engulfed by forming a vacuole around it.

2. Digestion: Food particles are broken by digestive enzymes inside the food vacuole.

3. Absorption: Digested food gets diffused into the cytoplasm and the food vacuole disappears after digestion.

4. Egestion: Removal of undigested food from amoeba.

Question:74

Describe the alimentary canal of man.

Answer:

Alimentary canal of man: It measures about 8 to 10 meters starting further on the mouth and aextendingndstothe the l the anus.

1. Mouth: It consists of the oral cavity which contains the lips, the inside lining of the lips and cheeks, teeth, gums, the front two-thirds of the tongue, the floor of the mouth below the tongue, and the bony roof of the mouth.
   Fois is broken into small parts and salivary glands secrete saliva which is mixed with the food by the tongue.

2. PharThe oral Oral cavity opens the into pharynx. The swallowing mechanism guides masticated food down to the stomach.

3. Oesophagus: A muscular tube connecting the pharynx to the stomach. Muscular movement in the oesophagus moves the food to the stomach.

4. Stomach: It is a J-shaped sac-like muscular structure where masticated food is mixed with gastric juices which are secreted by the lining of the stomach.

5. Small intestine: It is a tube-like structure about 6 meters where pancreatic juice and bile juice get mixed. SThesmall intestine is rich with blood vessels where chemical digestion happens and the food is absorbed and delivered to all the parts of the body.

6. Large intestine: Unabsorbed food is sent to the large intestine where water is absorbed from this food. The rest of it is removed from the body via the anus. The exit of waste material is regulated by anal sphincter.

Question:75

Explain the process of breathing in man.

Answer:

Inspiration: When we breathe in te,tdiaphragmragm contracts the lungslungss expand. When air is sucked in from the outside into the lungs, the lungs get filled with air.

Gaseous Exchange: Hemoglobin in red blood cells binds with oxygen delivery to all the cells and takes carbon dioxide from the cells. Carbon dioxide-rich haemoglobin inn comes back the to lungs where carbon dioxide is exchanged with oxygen onthen alveolar surface.

Expiration: When we breathe out, our lungs contract and push the carb dioxide-which air (where the carbon dioxide from the cells has reached the alveoli agents get exchanged for oxygen)

Question:76

Explain the importance of soil for plant growth.

Answer:

Importance of soil for plant growth.

1) Soil provides the point of anchorage for all the plants.

2) Soil is the reservoir for water and minerals which are essential for all the metabolic activities of a plant.

3) Roots of plants absorb oxygen diffused in soil for respiration purposes.

4) Some plants have symbiotic relationships with bacteria and fungi in the soil to fulfil their nitrogen requirements.

Question:77
Draw the diagram of the alimentary canal of man and label the following parts. Mouth, Oesophagus, Stomach, Intestine

Answer:

Question:78

How do carbohydrates, proteins and fats get digested in human beings?

Answer:

Digestion of carbohydrates:

Oral cavity: Starch is broken down into maltose by salivary amylase present in the saliva.

Small intestine remainingng starch is broken down into maltose by pancreatic amylase present in the pancreatic juice

M.altose is broken down into glucose units by the Maltase of intestinal juice.

Digestion of Proteins:

Protein digestion does not start in the roralcavity as the mouth does not have any digesting enzyme for proteins.

Stomach: The stomach secretes pepsin which is a protein-digesting enzyme. In its inactive form, pepsin is called pepsinogen.

Upon exposure to HCl, pepsinogen gets converted to active pepsin.

Pepsin starts protein digestion into small peptides.

Small intestine:

Trypsin and chymotrypsin digest proteins into peptides. Pancreatic juice secretes Trypsinogen, and chymotripsinogen (inactiformrom of trypsin).

Peptidases of intestinal juice digest the peptides into amino acids.

Digestion of Fats:

Small intestine:

Emulsification of large globules of fats into smaller droplets by bile salt.

Pancreatic lipase digests the emulsified fat globules into glycerol and fatty acids.

Glycerol and fatty acids enter the villi cells where they are rejoined and packaged as lipoprotein droplets before entering the lacteals.

Question:79

Explain the mechanism of photosynthesis.

Answer:

The process in which green plants convert carbon dioxide and water into glucose in the presence of chlorophyll and sunlight is called photosynthesis.

$6C{O}_2+12H_{2}O+Chlorophyll+Sunlight\to C_6{H}_{12}{O}_6+6O_2+6H_{2}O$Step-by-stepp process of photosynthesis

SSunlightis absorbed by the green pigment called chlorophyll.

2) The light is converted into chemical energy

3) Water molecule is split into hydrogen and oxygen. Oxygen produced by splitting the water molecule is released into

atmosphere

4) Hydrogen formed by splitting water molecules is utilized tby he oeduction of carbon dioxide to focarbohydratesate (glucose)

5) The extra glucose is stored as starch in the leaves of the plant

Question:80

Explain the three pathways of breakdown in living organisms.

Answer:

Glucose is a 6-carbon molecule, while pyruvate is a 3-carbon molecule. In all organisms, glucose is first converted into pyruvate in the cytoplasm.

Further breakdown of pyruvate can happen in any of the following ways:

• In Yeast: The breakdown of pyruvate takes place in the absence of oxygen. Pyruvate is broken down into ethanol and carbon dioxide. It is called anaerobic respiration.

• In mitochondria: The breakdown of pyruvate takes place in the presence of oxygen. Pyruvate is broken down into carbon dioxide and water. It is called aerobic respiration. It is found in most of the living beings.

• In muscle cells: The energy demand from muscle cells suddenly increases during strenuous physical activities. This is compensated by anaerobic respiration in muscle cells. In this, pyruvate is broken down into lactic acid.

Question:81

Describe the flow of blood through the heart of human beings.

AnsweThe flow of blood through the heart:

Oxygen-rich blood reaches the thin-walled upper chamber of the heart onto the left atrium from the lungs. The left atrium relaxes and collects blood; then contracts to enter the next chamber (the left ventricle), which expands so blood gets collected into it. MuTThescularentricle contracts and pumps oxygen-rich blood to all parts of the body.

Deoxygenated blood from the body comes to the upper chamber on the right side (the right atrium), and it expands. As the right atrium contracts, the corresponding lower chamber (the right ventricle) relaxes. This transfers blood to the right ventricle which in turn pumps into the lungs for oxygenation. This process is repeated continuously to fulfil the oxygen needs of the body.

The blood circulatory system in humans is double circulation as blood reaches the heart twice in one complete cycle.

1) The pathway of blood from the heart to the lungs and back to the heart is called pulmonary circulation.

2) The pathway of blood from the heart to the rest of the body and back to the heart is called systemic circulation.

Systemic Circulation + Pulmonary Circulation = Double Circulation

Question:82

Describe the process of urine formation in kidneys.

Answer:

The excretory system of human beings includes a pair of kidneys, a pair of ureters, a urinary bladder and a urethra. Kidneys are located in the abdomen, one on either side of the backbone. Urine produced in the kidneys passes through the ureters into the urinary bladder where it is stored until it is released through the urethra.

Each kidney has a cluster of very thin-walled blood capillaries. Each capillary cluster in the kidney is associated with the cup-shaped end of a tube that collects the filtered urine. Each kidney has large numbers of these filtration units called nephrons packed close together. Some substances in the initial filtrate, such as glucose, amino acids, salts and a major amount of water, are selectively re-absorbed as the urine flows along the tube.

The amount of water reabsorbed depends on how much excess water there is in the body, and on how much dissolved waste there is to be excreted. The urine forming in each kidney eventually enters a long tube, the ureter, which connects the kidneys with the urinary bladder. Urine is stored in the urinary bladder until the pressure of the expanded bladder leads to the urge to pass it out through the urethra.

NCERT Class 10 Exemplar Solutions for Other Subjects:

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NCERT Class 10 Science Exemplar Solutions for Other Chapters:

The exemplar solutions for all the chapters in science are given below-

NCERT Exemplar class 10 Science Solutions Chapter 5- Important Topics and Subtopics

The NCERT Exemplar Solutions for Class 10 Science has questions of different types that cover the whole chapter of the NCERT book. Let's take a quick look at the topics and subtopics covered in the Class 10 Science Chapter 5.

1. What Are Life Processes?

2. Nutrition

• Autotrophic Nutrition

• Heterotrophic Nutrition

• How do Organisms obtain their Nutrition?

• Nutrition in Human Beings

3. Respiration

4. Transportation

5. Excretion

Also, Check NCERT Books and NCERT Syllabus here

• NCERT Books Class 10 Science

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• NCERT Books Class 10

• NCERT Syllabus Class 10

NCERT Class 10 Science Solutions for Other Chapters:

The NCERT Solutions for all chapters of class 10 are given below-

Must check NCERT Solution Subject Wise

• NCERT Solution for Class 10 Science

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NCERT exam class 10 science solutions for chapter 5 provide a comprehensive understanding of life processes which include various life processes that occur in living organisms. The short and long-answer questions include well-structured explanations, diagrams and problem-solving exercises that help students understand the essential biological functions. Practising the MCQ of Chapter 5 enables students to test their knowledge and improve accuracy for competitive exams. Additionally, referring to the given important questions helps in identifying frequently asked topics. All these make sure thorough exam preparation is done, and students can review key concepts, making it easier to understand complex biological mechanisms.

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