CHAPTER – LIFE PROCESSES - Classroom Mentor

VOLUME-01

CHAPTER – LIFE PROCESSES

MULTIPLE CHOICE QUESTIONS

The role of chlorophyll in photosynthesis is for-
I. Absorbing light
II. Breaking down water molecule
III. No function
IV. Reduction of \( CO_2 \)
Ans- I. Absorbing light
Temporary finger like extensions made by Amoeba are called
I. Cell membrane
II. Cell wall
III. Pseudopodia
IV. Cilia
Ans- III. Pseudopodia
Bile juice is secreted by
I. Stomach
II. Pancreas
III. Small intestine
IV. Liver
Ans- IV. Liver
Respiratory pigment in human body is
I. Chlorophyll
II. Water
III. Blood
IV. haemoglobin
Ans- IV. haemoglobin
Which of the following is not a component of blood-
I. Lymph
II. Platelets
III. Plasma
IV. WBC
Ans- I. Lymph
One cell-thick vessels are called
I. Arteries
III. Capillaries
IV. Pulmonary artery
Ans- III. Capillaries
Which of the following is not a part of nephron?
I. PCT
II. DCT
III. Loop of Henle
IV. Ureter
Ans- IV. Ureter
Lipase acts on
I. Amino acids
II. Fats
III. Carbohydrates
IV. All of these
Ans- II. Fats
Which of these enzymes are secreted by pancreas?
I. Trypsin
II. Pepsin
III. Carboxypeptidase
IV. Both I and II
Ans- I. Trypsin
Cuscuta is a total plant parasite because-
I. It lacks chlorophyll
II. It has special roots to suck cell sap
III. It feeds on insects
IV. Both I and II
Ans- IV. Both I and II

ASSERTION REASON QUESTIONS

There are two statements, one labelled as Assertion(A) and the other labelled as Reason (R). Answer these questions selecting the appropriate option given below-

a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true and R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true

Assertion: Cuscuta is devoid of chlorophyll.
Reason: Cuscuta is a total plant parasite.
Assertion: Ascent of sap is due to transpirational pull and root pressure.
Reason: Food prepared during photosynthesis is transported by this process.
Ans- c) A is true but R is false.

VERY SHORT ANSWER TYPE QUESTIONs

“The breathing cycle is rhythmic whereas exchange of gases is a continuous process". Justify this statement// Comment// Why do the lungs always have some residual volume of air in them?
Ans- Breathing involves inhalation followed by exhalation. Gaseous exchange in alveoli occurs continuously as residual volume of air is present in alveoli all the time.
Give reasons for the following: //Why -
The small intestine of carnivores is smaller than that of herbivores.
Ans- Carnivores eat flesh which is easy to digest whereas herbivores eat plants which is rich in cellulose. It is difficult to digest. So, herbivores have a longer small intestine to increase surface area for complete digestion.
State the main function of arteries. Why do they have thick and elastic walls? // Mention two points of differences which make arteries different from veins.
Ans- Arteries except pulmonary artery carry pure/oxygenated blood. Blood moves with great pressure in arteries, to avoid bursting or arteries they have thick elastic walls.
Give reasons for the following // Why do- (2 marks each)
(a) Walls of trachea are supported by cartilage rings.
(b) Respiratory pigment- hemoglobin is required for transportation of gases.
(c) Breathing rate of aquatic organisms is much faster than that of terrestrial organisms.
Ans- (a)So that the walls of trachea do not collapse when there is no air in it.
(b) As diffusion pressure is not sufficient to supply \( O_2 \) to all the cells so respiratory pigment is required which carries \( O_2 \) to cells.
(c) Aquatic organisms take dissolved oxygen which is much less than atmospheric oxygen which is taken by terrestrial organisms. So, to meet the demand of oxygen aquatic organism breathe at a faster rate.
“Digestion of fats will take months if bile juice is not secreted by liver”. Justify this statement//Comment.// What is the role of bile juice in the digestion of fats?
Ans- Bile helps in emulsification of fats which increase the surface area. This allows faster action of enzyme lipase on fats.

SHORT ANSWER TYPE QUESTIONS

In human alimentary canal, name the site of complete digestion of various components of food. Write the end products of digestion of carbohydrates, fats and proteins. Explain the role of saliva in the process of digestion in mouth.
Ans- Small intestine
Fats- fatty acids and glycerol
Proteins- amino acids
Saliva has salivary amylase to break down starch into maltose
Schematically explain the process of breakdown of glucose in a cell// Depict in a flow chart the processes involved in breakdown of glucose in a cell
Ans-

(Break down of glucose by various pathways)
What is double circulation in human beings? Why is it necessary? // Why is double circulation important in warm blooded organisms? And how ?
Ans- In double circulation blood reaches twice to heart in one cycle (as pulmonary and systemic circulation).
It prevents mixing of pure and impure blood. So, more oxygen reaches the cells and more energy is produced. This is needed to maintain constant body temperature.

a) What is meant by ascent of sap and translocation of food? // Define.
b) How are these processes different from each other? // Differentiate between ascent of sap and translocation of food.
Ans- a) Ascent of sap is the upward movement of water and minerals through xylem in plants against gravity.
Translocation of food is the transport of photosynthate from leaf to all parts of plants through phloem.
c) Any one point of difference -

Ascent of sap	Translocation of food
Water and minerals are transported	Food prepared during photosynthesis is transported
Xylem vessels and tracheids are involved	Phloem sieve tubes are involved
Upwards movement against gravity occurs	Bidirectional movement occurs from leaves

Mention three strategies by which wastes are eliminated by the plants? // Do plants have an excretory system? How do these perform excretion? //
Plants make their food so they have minimum waste produced. How do the plants get rid of these wastes?
Ans- 1. Plants can get rid of excess water by transpiration.
2. Many plant waste products are stored in cellular vacuoles.
4. Other waste products are stored as resins and gums, especially in old xylem.
5. Plants also excrete some waste substances into the soil around them. (any 3 points) (1*3)

LONG ANSWER TYPE QUESTIONS

1. (a) Name the process by which autotrophs prepare their own food.
(b) List the three events which occur during this process.
(c) Write the balanced chemical equation for the process of photosynthesis in green plants.
Ans- (a) Photosynthesis
(b) Absorption of light energy by chlorophyll.
Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.
Reduction of \( CO_2 \) into carbohydrate.
(c) \( 6CO_2 + 12H_2O \xrightarrow{\text{sunlight \& chlorophyll}} C_6H_{12}O_6 + 6O_2 + 6H_2O \)
(a) Define excretion. What are the two organs in human beings that act as accessory excretory organs?
(b) Explain the steps involved in urine formation. //
Label P, Q, R, S. Mention which part is responsible for three main steps involved in urine formation.

Ans- (a) Excretion is the process of eliminating nitrogenous wastes from body.
Skin and liver
(b) Three steps – (i) Glomerular filtration of blood.
(ii) Reabsorption of useful substances by PCT.
(iii) Secretion by PCT and DCT .
P- glomerulus, Q- PCT, R- Henle’s loop, S- Collecting tubule
How do stomata open and close? Differentiate between desert plants and other plants on basis of stomatal opening and closure. Why is the difference in opening and closing of stomata? //
Label parts X, Y and Z. Explain the role of Z in opening and closing of stomata.

Ans- The opening and closing of the pore is a function of the guard cells. The guard cells swell when water flows into them, causing the stomatal pore to open. Similarly, the pore closes if the guard cells shrink.
Stomata open at night in desert plants to reduce transpiration. In other plants, stomata open at day time and close at night time to allow \( CO_2 \) and \( O_2 \) to enter into the cells. //
X- chloroplast, Y-stomata, Z- guard cell

CASE BASED QUESTIONS

1. Renu always eats junk food out and suffers from acidity. She was eating antacids to reduce the effect of hyper acidity when Aasfaq came. Renu asked her doubts about acidity to her. Considering yourself as Aasfaq answer the following questions of Renu-
a) (i)Why does a person suffer from acidity?
OR
(ii) Why is acid produced in stomach?
b) Why the stomach walls do not get damaged by the acid produced in stomach?
c) Name the acid and the gland which produces this acid.
Ans- a) (i) Hyper production of HCl in stomach causes acidity.
OR
(ii) Acidity kills the harmful microbes’ hat have entered with food and creates acidic environment to activate pepsin.
b) Due to mucus coating
c) Hydrochloric acid by gastric glands.
Two potted plants were kept in dark for 72 hours and then in sunlight in the given set up-

a) (i) What happens in bell jar A after few hours? How can this be tested in laboratory?
OR
(ii) What happens in bell jar B after few hours? How can this be tested in laboratory?
b) What is the role of potassium hydroxide in this experiment?
c) Write the aim of the above experiment.
Ans- a) (i) No photosynthesis occurs. No starch is produced which can be observed by doing iodine test. (1+1)
OR
(ii) Photosynthesis occurs. Starch is produced which can be observed by doing iodine test.
b) Absorbs \( CO_2 \)
c) To show \( CO_2 \) is necessary for photosynthesis.

CHAPTER-5-LIFE PROCESSES

WORKSHEET -(VOL-1)

Time: 30 minutes
Max. Marks : 25

Multiple Choice Questions (1Mark)

Which of the following enzymes is responsible for breaking down proteins in the stomach?
(a) Amylase
(b) Lipase
(c) Pepsin
(d) Maltase
Ans: (a) Pepsin
From the given picture of the digestive system, identify the part labelled as gastric gland.

(a) A
(b) B
(c) C
(d) D
Ans: (b)
The following image shows the bread moulds on bread. How do these fungi obtain nutrition?

i.
(a) By eating the bread on which it is growing
(b) By using nutrients from the bread to prepare their own food
(c) By breaking down the nutrients of bread and then absorbing them
(d) By allowing other organisms to grow on the bread and then consuming them.
Ans: (c) By breaking down the nutrients of bread and then absorbing them
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
Ans: (c) Oxidation of carbon to carbon dioxide
Which of the following equations is the summary of photosynthesis?
(a) \( 6CO_2 + 12H_2O \rightarrow C_6H_{12}O_6 + 6O_2 + 6H_2O \)
(b) \( 6CO_2 + H_2O + \text{Sunlight} \rightarrow C_6H_{12}O_6 + O_2 + 6H_2O \)
(c) \( 6CO_2 + 12H_2O + \text{Chlorophyll} + \text{Sunlight} \rightarrow C_6H_{12}O_6 + 6O_2 + 6H_2O \)
(d) \( 6CO_2 + 12H_2O + \text{Chlorophyll} + \text{Sunlight} \rightarrow C_6H_{12}O_6 + 6CO_2 + 6H_2O \)
Ans: (c) \( 6CO_2 + 12H_2O + \text{Chlorophyll} + \text{Sunlight} \rightarrow C_6H_{12}O_6 + 6O_2 + 6H_2O \)
In the sketch of stomatal apparatus given alongside, the parts I, II, III and IV were Labelled differently by four students. The correct labelling is shown in.

(a) (I) guard cells, (II) stoma, (III) starch granule, (IV) nucleus
(b) (I) cytoplasm, (II) nucleus, (III) stoma, (IV) chloroplast
(c) (I) guard cells, (II) starch, (III) nucleus, (IV) stoma
(d) (I) cytoplasm, (II) chloroplast, (III) stoma, (IV) nucleus
Ans: (b) (I) cytoplasm, (II) nucleus, (III) stoma, (IV) chloroplast
Slides A and B show stages of asexual reproduction in two different organisms. The slides A and B are depicting .

(a) binary fission in both Amoeba and Yeast
(b) budding in both Amoeba and Yeast
(c) binary fission in yeast and budding in Amoeba
(d) binary fission in Amoeba and budding in Yeast
Ans: (d) binary fission in Amoeba and budding in Yeast

Short Answer Questions (1 marks)

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 stomach that acts on proteins.
Ans: (a) Photosynthesis (b) Autotrophs (c) Chloroplast (d) Guard cells (e) Heterotrophs (f) Pepsin
How does the acidic medium in the small intestine is converted into alkaline for pancreatic enzymes? (1)
Ans: By the action of bile juice secreted by liver.
How do the guard cells regulate opening and closing of stomatal pores? (2)
Ans: The swelling of guard cells due to absorption of water causes opening of stomatal pores while shrinking of guard cells closes the pores
Match the terms in Column (A) with those in Column (B) (2 marks)

Column (A) Group (B)

(a) Trypsin (i) Pancreas

(b) Amylase (ii) Liver

(c) Bile (iii) Gastric glands

(d) Pepsin (iv) Saliva

Ans:
(a) Trypsin - (i) Pancreas
(b) Amylase - (iv) Saliva
(c) Bile - (ii) Liver
(d) Pepsin - (iii) Gastric glands.
Read the following and answer the questions: (4 marks)
Ayush experienced muscular cramps during the training session for his upcoming cricket match . His coach advised him on a schedule of aerobic exercises to overcome this problem. Ayush followed his coach’s advice and did not experience any muscular cramps during the game.
i. Lack of oxygen in muscles often leads to cramps due to
a. Conversion of pyruvate to ethanol.
b. non-conversion of glucose to pyruvate.
c. conversion of pyruvate to glucose.
d. conversion of pyruvate to lactic acid.
ii. Which substances are produced by anaerobic respiration in yeast?

Lactic acid Carbon dioxide

A Yes Yes

B Yes No

C No Yes

D No No

iii. Why there is an increase in increase in lactic acid concentration in the blood at the beginning of execise?
a. Lack of oxygen
b. Lack of carbondioxide
c. Excess of oxygen
d. Excess of carbon dioxide
iv. How does aerobic respiration differ from anaerobic respiration?
Ans:
i. d . conversion of pyruvate to lactic acid
ii. C
iii . a. Lack of oxygen
iv . Aerobic respiration occurs with oxygen and releases more energy but more slowly. Anaerobic respiration occurs without oxygen and releases less energy but more quickly.
Given below is an image of an experiment conducted by a student to understand the process of respiration. He blows into a clear solution present in the test tube and sees that it turns cloudy. (3 marks)

1. What is the most likely substance present in the test tube?
2. What could be the aim of his experiment?
3. What kind of respiration is shown in the experiment? Justify your answer.
Ans:
1. Substance is limewater, which is a solution of calcium hydroxide (\( Ca(OH)_2 \)).
2. The student's aim is to prove that carbon dioxide is released during respiration. When carbon dioxide is passed through limewater, it reacts with calcium hydroxide to form calcium carbonate, an insoluble compound that makes the solution appear cloudy or milky.
3. The experiment demonstrates aerobic respiration. This is because the exhaled air contains carbon dioxide, a byproduct of aerobic respiration (the process of using oxygen to produce energy in cells). While fermentation also produces carbon dioxide, it's not the primary process in human cells.

CHAPTER – LIFE PROCESSES

VOLUME-01