Question 1

Question 1(i)Duplicated chromosomes are joined at a point termed:CentrosomeCentromereCentrioleChromatid

Accepted Answer

CentromereReason — Duplicated chromosomes (sister chromatids) are joined at a point termed Centromere.

Question 2

Question 1(v)Which one of the following helps in the opening of stomata:Cobalt ionsPotassium ionsMagnesium ionsAluminium ions

Accepted Answer

Potassium ionsReason — During sunlight K⁺ ions rush into the guard cells. It is followed by osmosis. The guard cells then swell, and the stomata opens.

Question 3

Question 1(vi)A zygote which has Y chromosome inherited from the father will develop into a:Will depend on the chromosome inherited from the motherGirlEither boy or a girlBoy

Accepted Answer

BoyReason — Child always inherits X chromosome from the mother, and either X or Y chromosome from father. If X chromosome is inherited from father, a girl child develops and inheritance of a Y chromosome results in a boy.

Question 4

Question 1(x)Four friends P, Q, R and S were discussing the examples of genetic disorders. The examples they quoted were as follows:P. Colour blindness and MalariaQ. Albinism and CholeraR. Haemophilia and Colour blindnessS. Haemophilia and AlbinismWho gave the correct examples?P and QR and SP and RQ and S

Accepted Answer

R and SReason — Malaria and Cholera are not genetic disorders. They are caused by plasmodium and bacteria respectively. Haemophilia, Colour blindness and Albinism are genetic disorders.

Question 5

Question 1(xi)Osmosis takes place when there is:A freely permeable membraneA cell wallA selectively permeable membraneAn impermeable membrane

Accepted Answer

A selectively permeable membraneReason — Osmosis takes place through a selectively permeable, differentially permeable or semi-permeable membrane.

Question 6

Question 2(ii)Arrange and rewrite the terms in each group in the correct order to be in a logical sequence beginning with the term that is underlined:(a) Australopithecus, Cro-Magnon, Homo erectus, Neanderthal man.(b) Pupil, Aqueous humour, Retina, Vitreous humour.(c) Effector, Receptor, Motor neuron, Sensory neuron.(d) Loop of Henle, Distal convoluted tubule, Bowman’s Capsule, Proximal convoluted tubule.(e) Water vapour, Soil water, Leaves, Ascent of Sap

Accepted Answer

(a) Australopithecus → Homo erectus → Neanderthal man→ Cro-Magnon(b) Aqueous humour → Pupil→ Vitreous humour → Retina(c) Receptor→ Sensory neuron → Motor neuron→ Effector(d) Bowman’s Capsule → Proximal convoluted tubule→ Loop of Henle → Distal convoluted tubule(e) Soil water → Roots → Ascent of Sap → Leaves

Question 7

Question 2(iii)Study the diagram given below and fill in the blanks with suitable words:In order to prove that carbon dioxide is necessary for (a) ............... , a potted plant is placed in dark for 48 hours to (b) ............... the leaves. A part of a leaf is inserted into a conical flask containing potassium hydroxide solution. This is to absorb (c) ............... from the flask. The plant is then placed in sunlight for a few hours. The experimental leaf is tested for starch. The part of the leaf that was inside the conical flask turns (d) ............... , whereas the part of the leaf outside turns (e) ............... in colour.

Accepted Answer

In order to prove that carbon dioxide is necessary for (a) photosynthesis , a potted plant is placed in dark for 48 hours to (b) destarch the leaves. A part of a leaf is inserted into a conical flask containing potassium hydroxide solution. This is to absorb (c) carbon dioxide from the flask. The plant is then placed in sunlight for a few hours. The experimental leaf is tested for starch. The part of the leaf that was inside the conical flask turns (d) brown , whereas the part of the leaf outside turns (e) blue-black in colour.

Question 8

Question 2(iv)Choose the odd one out from the following terms and name the category to which the others belong:(a) Prothrombin, Thrombin, Fibrinogen, Albumin(b) Tonsils, Glomerulus, Spleen, Lymph nodes(c) Neutrophils, Basophils, Monocytes, Eosinophils(d) Leaves, Styrofoam, Grass, Cow Dung(e) Pulmonary artery, Renal artery, Coronary artery, Hepatic artery

Accepted Answer

(a) Odd one : AlbuminProthrombin, Thrombin, Fibrinogen — Involved in clotting of blood.(b) Odd one : GlomerulusTonsils, Spleen, Lymph nodes — Parts of the lymphatic system.(c) Odd one : MonocytesNeutrophils, Basophils, Eosinophils — Granular WBCs or Granulocytes.(d) Odd one : StyrofoamLeaves, Grass, Cow Dung — Biodegradable substances.(e) Odd one : Pulmonary arteryRenal artery, Coronary artery, Hepatic artery — Carry oxygenated blood.

Question 9

Question 3(ii)Mention two adaptations in roots for absorption of water from the soil.

Accepted Answer

Two adaptations in roots for absorption of water from the soil are:The roots have numerous root hairs that increase the surface area for absorption.The cell wall of root hair is thin and permeable and the cell membrane is thin and semi-permeable.

Question 10

Question 3(iii)Differentiate between Afferent arteriole and Efferent arteriole (diameter).

Accepted Answer

Difference between Afferent arteriole and Efferent arteriole (diameter):Afferent arteriole — This arteriole is larger in diameter compared to the efferent arteriole.Efferent arteriole — This arteriole is smaller in diameter compared to the afferent arteriole.

Question 11

Question 3(iv)Give two examples of water pollutants.

Accepted Answer

Two examples of water pollutants are:Pesticides — Chemicals used in agriculture and pest control can leach into water bodies, contaminating them and posing risks to aquatic life and human health.Heavy metals — Metals such as lead, mercury, cadmium, and arsenic can enter water sources through industrial discharge and careless disposal of electronic wastes and contaminate it.

Question 12

Question 4(ii)State two harmful effects of acid rain on the environment.

Accepted Answer

Two harmful effects of acid rain on the environment are:Damage to aquatic life — Acid rain can lower the pH of water bodies, making them acidic. This acidity can harm aquatic organisms such as fish, amphibians, and aquatic plants.Erosion of buildings and monuments — Acid rain corrodes building materials like limestone and marble, leading to the deterioration of historical monuments and structures.

Question 13

Question 4(iii)Mention two advantages of Transpiration.

Accepted Answer

Two advantages of transpiration are:Cooling effect — Transpiration helps regulate plant temperature by releasing water vapour through stomata, which cools the plant and its immediate surroundings.Transport of nutrients — Transpiration creates a negative pressure gradient in the xylem, facilitating the movement of water and minerals from the roots to the shoots and leaves of the plant.

Question 14

Question 4(iv)Write any two objectives of Swachh Bharat Abhiyan.

Accepted Answer

Two objectives of Swachh Bharat Abhiyan (Clean India Mission) are:To eliminate open defecation — The mission aims to ensure that all households have access to toilets and promote the construction and use of sanitary latrines.To promote cleanliness and hygiene — It seeks to create awareness about sanitation and cleanliness practices, improve waste management systems, and maintain cleanliness in public spaces.

Question 15

Question 5(ii)Differentiate between Australopithecus and Modern man based on body hair.

Accepted Answer

Difference between Australopithecus and Modern man based on body hair:AustralopithecusModern manBody hair covered much of the body of Australopithecus.Modern man has highly reduced body hair.

Question 16

Question 5(iii)"Birth rate in India is very high." Mention two reasons in support of the statement.

Accepted Answer

The birth rate in India is very high because :Economic reasons — Children are considered to be helping hands to increase the family income.Religious and Social Customs — India is a centre of various religious and social customs, and as such most people do not accept family planning norms.

Question 17

Question 5(iv)Give the exact location of:(a) Pericardium(b) Bicuspid valve

Accepted Answer

(a) Pericardium — Protective double-walled membranous covering that surrounds the heart.(b) Bicuspid valve — Located between the left atrium and the left ventricle of the heart.

Question 18

Question 5(v)Given below is a schematic representation of the inheritance of the shape of seeds of garden pea. Answer the questions that follow:(a) Which is the dominant and recessive allele of the trait?(b) What does the ratio 3 : 1 in the F2 generation represent?(c) State Mendel’s Law of Dominance.

Accepted Answer

(a) The allele for smooth seeds are dominant over wrinkled seeds which are recessive.(b) The ratio 3:1 indicates the observed ratio of different phenotypes (observable traits) in the F2 generation. It means that out of every 4 individuals in the F2 generation, approximately 3 individuals will exhibit one phenotype (typically the dominant trait) and 1 individual will exhibit the other phenotype (typically the recessive trait).(c) Out of a pair of contrasting characters present together, only one is able to express itself while the other remains suppressed. The one that expresses is the dominant character and the one that is unexpressed is the recessive one.

Question 19

Question 6(i)Define the term-Diapedesis.

Accepted Answer

Diapedesis is the process by which white blood cells (WBCs) squeeze through capillary walls into tissues, using amoeboid-like extensions called pseudopodia to reach sites of infection or inflammation.

Question 20

Question 6(v)Draw a neat, labelled diagram of a chloroplast.

Accepted Answer

Labelled diagram of the chloroplast is shown below:

Solved 2024 Question Paper ICSE Class 10 Biology

Section A

Section B