ICSE Class 10 Biology — 2024 Paper

Centromere

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

Photophosphorylation

Reason — Photophosphorylation is the synthesis of ATP (adenosine triphosphate) from ADP (adenosine diphosphate) and inorganic phosphate (P_i) using light energy (photons).

Guttation

Reason — Guttation is the exudation of water from the tip or edges of leaves of some herbaceous plants.

Vasopressin

Reason — Vasopressin is produced by the posterior pituitary gland. Also known as ADH (Anti-diurectic hormone), it plays role in reabsorption of water in kidneys.

Potassium ions

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

Boy

Reason — 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.

Stapes

Reason — It is the smallest bone in the human body and plays a crucial role in transmitting sound vibrations from the tympanic membrane (eardrum) to the oval window of the cochlea in the inner ear.

P, Q and R

Reason — Engaging in conversation may exhaust the patient. Loosening clothes, ventilated room and taking the patient to the hospital are things that should be done as quickly as possible.

Ciliary muscles

Reason — The contraction and relaxation of ciliary muscles lead to adjustment of focal length of eye.

R and S

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

A selectively permeable membrane

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

24

Reason — Gametes are haploid i.e., they have half the number of chromosomes present in somatic cells.

Both A and R are True

Reason — The Sympathetic nervous system prepares our body for action when faced with danger, stress, or excitement. It’s the ultimate “fight-or-flight” response coordinator.

1 year

Reason — Birth rate represents the total number of live human births per 1,000 population during a year.

Peppered Moth

Reason — This phenomenon refers to the darkening of the moth's wings due to natural selection driven by pollution-induced changes in the environment during the Industrial Revolution in England.

(a) Root hairs

(b) Astigmatism

(c) Chemotropism

(d) Urea

(e) Implantation

(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 → Ascent of Sap → Leaves → Water vapour

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.

(a) Odd one : Albumin
Prothrombin, Thrombin, Fibrinogen — Involved in clotting of blood.

(b) Odd one : Glomerulus
Tonsils, Spleen, Lymph nodes — Parts of the lymphatic system.

(c) Odd one : Monocytes
Neutrophils, Basophils, Eosinophils — Granular WBCs or Granulocytes.

(d) Odd one : Styrofoam
Leaves, Grass, Cow Dung — Biodegradable substances.

(e) Odd one : Pulmonary artery
Renal artery, Coronary artery, Hepatic artery — Carry oxygenated blood.

NADP - Nicotinamide Adenine Dinucleotide Phosphate.

Two adaptations in roots for absorption of water from the soil are:

1. The roots have numerous root hairs that increase the surface area for absorption.
2. The cell wall of root hair is thin and permeable and the cell membrane is thin and semi-permeable.

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.

Two examples of water pollutants are:

1. Pesticides — Chemicals used in agriculture and pest control can leach into water bodies, contaminating them and posing risks to aquatic life and human health.
2. 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.

(a) Thigmotropism.

(b) The growth movement of plant parts in response to touch stimulus is called Thigmotropism.

(c) X → Leaf Tendril

Tubectomy.

Two harmful effects of acid rain on the environment are:

1. 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.
2. Erosion of buildings and monuments — Acid rain corrodes building materials like limestone and marble, leading to the deterioration of historical monuments and structures.

Two advantages of transpiration are:

1. Cooling effect — Transpiration helps regulate plant temperature by releasing water vapour through stomata, which cools the plant and its immediate surroundings.
2. 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.

Two objectives of Swachh Bharat Abhiyan (Clean India Mission) are:

1. 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.
2. 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.

(a) Frontal lobe or cerebral cortex.

(b) Eyes.

(c) Cerebellum.

Mixed nerve.

Difference between Australopithecus and Modern man based on body hair:

The birth rate in India is very high because :

1. Economic reasons — Children are considered to be helping hands to increase the family income.
2. 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.

(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.

(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.

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.

Difference between Diabetes mellitus and Diabetes insipidus based on the endocrine gland concerned:

Haemoglobin has very strong affinity for carbon monoxide, forming a stable compound carboxyhaemoglobin. This cuts down the capacity of blood for transporting oxygen, sometimes resulting in death. Hence, Carbon monoxide is highly dangerous when inhaled.

(a) Ovulation

(b) Corpus luteum

Labelled diagram of the chloroplast is shown below:

Hormone is a secretion from some glandular part of the body, which is poured directly into blood and which acts on the target organs or cells of the same individual, bringing about coordination between distant parts of the body.

(a) Static equilibrium : Vestibule

(b) Dynamic equilibrium : Semicircular canals

Two structural differences between an artery and a vein are:

Two limitations of using a Ganong's Potometer to demonstrate the uptake of water are:

1. It is not easy to introduce an air bubble into the apparatus.
2. Any changes in the outside air temperature may affect the position of the air bubble in the capillary tube.

(a) Mahesh is suffering from myopia, also known as nearsightedness.

(b) In myopia, the image is formed in front of the retina, instead of directly on the retina.

(c) To correct myopia, Mahesh would need concave lenses.

The blood flows through the glomerulus under great pressure which causes the liquid part of the blood to filter out from the glomerulus into the renal tubule. This filtration under high force is called Ultrafiltration.

(a) Clotting of blood : Calcium

(b) Synthesis of thyroxine : Iodine

Two harmful effects of noise pollution are:

1. Sleep disturbances
2. Hearing loss

RBCs are efficient in their functions though they lack nucleus and mitochondria because:

1. Loss of nucleus makes the red cells biconcave, thus increasing their surface area to absorb more oxygen.
2. Loss of mitochondria means that they cannot use the absorbed oxygen themselves. Thus, all the oxygen absorbed from the lungs is transported and delivered to the tissues unconsumed.

(a) Early Anaphase

(b) In Early Anaphase the sister chromatids separate and start moving towards the opposite poles. This is due to contraction of spindle fibre.

(c) There are four chromosomes in the given diagram.