Solved 2023 Question Paper ICSE Class 10 Biology

Section A

Question 1(i)

The sex chromosome in a human ovum is:

1. X chromosome
2. Y chromosome
3. Both X and Y chromosomes
4. Either X or Y chromosome

Answer

X chromosome

Reason — Human ovum have 'XX' as pair of sex chromosomes.

Question 1(ii)

Which one of the following is a biodegradable waste?

1. Metal cans
2. E-waste
3. Plastic
4. Flowers

Answer

Flowers

Reason — Biodegradable waste refers to organic materials that can be broken down naturally by microorganisms and environmental processes. Flowers are a type of organic waste that can decompose over time, making them biodegradable whereas metal cans, e-waste, plastic are non-biodegradable waste.

Question 1(iii)

The heart sound 'Dup' is produced when:

1. Semilunar valves open
2. Atrio ventricular valves close
3. Semilunar valves close
4. Atrio ventricular valves open

Answer

Semilunar valves close

Reason — 'Dup' sound is produced at the beginning of ventricular diastole when the semilunar valve at the root of aorta and pulmonary artery close.

Question 1(iv)

Deplasmolysis occurs when a plasmolysed cell is placed in:

1. Concentrated salt solution
2. Tap water
3. Concentrated sugar solution
4. Hypertonic salt solution

Answer

Tap water

Reason — When plasmolysed cell is placed in Tap water (hypotonic solution), the cell absorbs water and becomes normal. This is known as deplasmolysis.

Question 1(v)

Alpha cells of Pancreas secrete:

1. Glycogen
2. Glucose
3. Glucagon
4. Insulin

Answer

Glucagon

Reason — Alpha cell of islet of Langerhans in Pancreas secrete glucagon. It stimulates liver to convert glycogen into glucose.

Question 1(vi)

Haploid number of chromosomes are found in:

1. Nephrons
2. Neurons
3. Skin cells
4. Sperms

Answer

Sperms

Reason — The gametes (sperm or ovum) are formed as a result of meiosis in which the number of chromosomes are halved.

Question 1(vii)

The life span of an RBC is:

1. 120 days
2. 220 days
3. 20 days
4. 2 weeks

Answer

120 days

Reason — The life span of an RBC is 120 days.

Question 1(viii)

The statistical study of human population is called:

1. Mortality
2. Demography
3. Natality
4. Equality

Answer

Demography

Reason — Demography is the term given to the statistical study of human population.

Question 1(ix)

The pale yellow colour of normal human urine is due to the pigment:

1. Melanin
2. Anthocyanin
3. Urochrome
4. Haemoglobin

Answer

Urochrome

Reason — Urochrome is the pigment responsible for pale yellow colour of normal human urine.

Question 1(x)

Stimulation of the nerves of the sympathetic nervous system:

1. Accelerates heartbeat
2. Constricts pupil of eyes
3. Increases peristalsis
4. Retards heartbeat

Answer

Accelerates heartbeat

Reason — The sympathetic nervous system prepares the body for emergency situations.

Question 1(xi)

The site of light reaction in the cells of a green leaf is:

1. Nucleus
2. Grana of chloroplast
3. Cytoplasm
4. Stroma of chloroplast

Answer

Grana of chloroplast

Reason — The site of light reaction in the cells of a green leaf is grana of chloroplast which has chlorophyll.

Question 1(xii)

The paper used to demonstrate unequal transpiration in a dicot leaf is:

1. Filter paper
2. Litmus paper
3. Starch paper
4. Cobalt chloride paper

Answer

Cobalt chloride paper

Reason — Cobalt chloride paper turns from blue to pink when exposed to moisture. Hence, it is used to demonstrate unequal transpiration in a dicot leaf.

Question 1(xiii)

Vitreous humour is present between:

1. Cornea and Iris
2. Lens and Retina
3. Iris and Lens
4. Cornea and Lens

Answer

Lens and Retina

Reason — Vitreous humour is present between lens and retina. It provides nutrition to eye.

Question 1(xiv)

Oxygenated blood to liver is supplied by:

1. Hepatic artery
2. Hepatic vein
3. Inferior vena cava
4. Hepatic portal vein

Answer

Hepatic artery

Reason — Oxygenated blood to liver is supplied by hepatic artery.

Question 1(xv)

During the synthesis phase of the cell cycle, more of:

1. RNA is synthesised
2. RNA and proteins are synthesised
3. DNA is synthesised
4. Glucose is synthesized

Answer

DNA is synthesised

Reason — During the synthesis phase (S phase) of the cell cycle, the primary focus is on the synthesis of DNA. This phase is when the cell replicates its DNA in preparation for cell division.

Question 2(i)

Name the following:

(i) The organelle that forms the aster during cell division.

(ii) A genetic disorder in which the blood does not clot.

(iii) The permanent stoppage of menstruation in human females around the age of 45 years.

(iv) The openings on the barks of trees through which transpiration occurs.

(v) A gaseous plant hormone which promotes ripening of fruits.

Answer

(i) Centriole

(ii) Hemophilia

(iii) Menopause

(iv) Lenticels

(v) Ethylene

Question 2(ii)

Arrange and rewrite the terms in each group in correct order to be in a logical sequence beginning with the term that is underlined:

(a) Snake, Rabbit, Cabbage, Hawk.

(b) Xylem, Soil water, Cortical cells, Root hair.

(c) Receptor, Response, Effector, Spinal Cord.

(d) Fovea, Lens, Cornea, Conjunctiva.

(e) Testis, Urethra, Sperm duct, Epididymis.

Answer

(a) Cabbage → Rabbit → Snake → Hawk.

(b) Soil water → Root hair → Cortical cells → Xylem

(c) Receptor → Spinal Cord → Effector → Response

(d) Conjunctiva → Cornea → Lens → Fovea

(e) Testis → Epididymis → Sperm duct → Urethra

Question 2(iii)

Match the items given in Column I with most appropriate ones in Column II and rewrite the correct matching pairs:

Answer

Question 2(iv)

Choose the odd one out from the following terms and name the category to which the others belong:

(a) Used bandages, Pesticides, Face masks, Syringes.

(b) Dust, Smoke, Carbon monoxide, Effluents

(c) Uterus, Urethra, Urinary bladder, Ureter

(d) Menstrual phase, Telophase, Follicular phase, Luteal phase

(e) Malleus, Incus, Cochlea, Stapes

Answer

(a) Odd one : Pesticides
Used bandages, Face masks, Syringes — Bio-medical wastes

(b) Odd one : Effluents
Dust, Smoke, Carbon monoxide — Air pollutant

(c) Odd one : Uterus
Urethra, Urinary bladder, Ureter — Parts of Excretory System

(d) Odd one : Telophase
Menstrual phase, Follicular phase, Luteal phase — Menstrual cycle

(e) Odd one : Cochlea
Malleus, Incus, Stapes — Ear ossicles

Question 2(v)

State the exact location of the following structures:

(a) Thyroid gland

(b) Dura mater

(c) Amniotic fluid

(d) Papillary muscles

(e) Islets of Langerhans

Answer

(a) Thyroid gland → Infront of neck below larynx.

(b) Dura mater → The outermost membrane covering the brain directly under skull.

(c) Amniotic fluid → In the space between the amnion and the embryo.

(d) Papillary muscles → Lower portion of the interior walls of the ventricles.

(e) Islets of Langerhans → Pancreas.

Section B

Question 3(i)

Write the overall chemical equation for photosynthesis.

Answer

Balanced chemical equation representing the process of photosynthesis is given below:

$6\text{CO}_2 + 12\text{H}_2\text{O} \xrightarrow[\text{chlorophyll}]{\text{light energy}} \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{H}_2\text{O} + 6\text{O}_2 \uparrow$

Question 3(ii)

Mention any two functions of blood.

Answer

Two functions of blood are:

1. Transport of digested food (in the form of simple sugars like glucose, amino acids, vitamins, mineral salts, etc.) from the alimentary canal to the tissues.
2. Transport of oxygen from the lungs to the tissues by means of haemoglobin present in red blood cells.

Question 3(iii)

Differentiate between Karyokinesis and Cytokinesis.

Answer

Question 3(iv)

Excessive use of fertilizers in agricultural fields reduces the yield of crops. Justify the statement.

Answer

Excessive use of fertilizers in agricultural fields leads to accumulation of unused chemicals in soil. The soil becomes either acidic or basic, making the soil unfit for cultivation. Also the beneficial microorganisms present in the soil are killed due to chemicals and disturbed ph of soil. Therefore, excessive use of fertilizers in agricultural fields reduces the yield of crops.

Question 3(v)

Study the diagram given below and answer the questions that follow:

(a) Name the phenomenon depicted by the shoot in the above diagram.

(b) Which plant hormone plays an important role in the above movement?

(c) Complete and rewrite the given statement by filling in the correct terms:

Shoots show positive ............... whereas, roots show positive ............... .

Answer

(a) Phototropism

(b) Auxin

(c) Shoots show positive phototropism whereas, roots show positive geotropism .

Question 4(i)

Expand the abbreviation — DNA.

Answer

DNA — Deoxyribonucleic acid.

Question 4(ii)

What is Active transport?

Answer

Active transport is the passage of a substance (salt or ion) from its lower to higher concentration through a living cell membrane using energy from the cell.

Question 4(iii)

Mention the two pairs of nitrogenous bases which pair with each other with hydrogen bonds.

Answer

Adenine pairs with thymine with two hydrogen bonds.

Cytosine pairs with Guanine with three hydrogen bonds.

Question 4(iv)

State Mendel's 'Law of Segregation'.

Answer

Law of Segregation (also called the law of purity of gametes) — The two members of a pair of factors separate during the formation of gametes. They do not blend but segregate or separate into different gametes. The gametes combine together by random fusion at the time of zygote formation.

Question 4(v)

Draw a neat, labelled diagram of a human sperm.

Answer

Labelled diagram of a human sperm is shown below:

Question 5(i)

Explain the term 'Population density'.

Answer

Population density is the number of individuals per square kilometre (km²) at any given time.

Question 5(ii)

Name the two surgical methods of population control.

Answer

The two surgical methods of population control are:

1. Tubectomy
2. Vasectomy

Question 5(iii)

Mention two factors responsible for population explosion in India.

Answer

Two factors responsible for population explosion in India are:

1. Desire for a male child.
2. Illiteracy and Lack of awareness about birth control measures.

Question 5(iv)

Name any two resources which come under pressure due to rising population.

Answer

Two resources which come under pressure due to rising population are:

1. Water
2. Land

Question 5(v)

The diagram given below depicts the climate change on planet Earth. Answer the following questions:

(a) Name the climatic phenomenon for the increase in Earth's temperature.

(b) Mention one reason for this warming.

(c) What measure can be taken to prevent this climate change?

Answer

(a) Global warming

(b) Green house effect due to accumulation of greenhouse gases like Carbon dioxide (CO₂) and Methane (CH₄) in the atmosphere.

(c) To prevent global warming, use of fossil fuels should be minimized and renewable energy sources should be adopted rapidly. Deforestation should be stopped and more trees should be planted.

Question 6(i)

Define the term Transpiration.

Answer

Transpiration is the loss of water in the form of water vapour from the aerial parts (leaves and stem) of the plant.

Question 6(ii)

State any two adaptations in plants to reduce transpiration.

Answer

1. Sunken stomata : The stomata may be sunken or covered by hairs.
2. Narrow leaves : They have reduced surface area and hence reduced transpiration.

Question 6(iii)

Mention any two functions of the human foetal placenta.

Answer

Two functions of the human foetal placenta are:

1. Placenta provides the foetus with oxygen and nutrients.
2. Placenta also removes carbon dioxide and waste products of the foetus.

Question 6(iv)

What is the significance of the human testes being located in scrotal sacs outside the abdomen?

Answer

Testes are responsible for the production of male gametes i.e., sperms. The normal body temperature does not allow the maturation of the sperms. Being suspended outside the body cavity, the temperature in the scrotal sac is 2 to 3°C lower than that of the body which is the suitable temperature for the maturation of the sperms.

Question 6(v)

Draw a neat, labelled diagram of a Malpighian Capsule.

Answer

Below labelled diagram shows Malpighian Capsule:

Question 7(i)

What is a Reflex action?

Answer

Reflex action is an automatic/quick/immediate involuntary action in the body brought about by a stimulus.

Question 7(ii)

Renal cortex has a dotted appearance and Renal medulla has a striped appearance. Explain.

Answer

The Bowman's capsule and the proximal convoluted part of all the nephrons lie in the cortex of kidneys giving it a dotted appearance. Henle's loops and collecting ducts lie in the renal medulla giving it a striped appearance.

Question 7(iii)

What are the two functions of cerebellum.

Answer

The two functions of cerebellum are:

1. Maintains balance of the body.
2. Coordinates muscular activity.

Question 7(iv)

Distinguish between Semicircular canals and Utriculus based on their function.

Answer

Semicircular canals help to keep the dynamic balance of the body while utriculus helps in maintaining static balance of the body.

Question 7(v)

A potted plant with variegated leaves was kept in dark for 24 hours and then placed in bright sunlight. Answer the following questions.

(a) Which aspect of photosynthesis is being tested in the above diagram?

(b) Why was the plant kept in dark for 24 hours?

(c) After the starch test what will be the colour of the yellow and green parts of the leaf? Give reasons to support your answer.

Answer

(a) Presence of chlorophyll is necessary for photosynthesis.

(b) The plant is kept in dark for 24 hours to to destarch the leaves.

(c) After conducting the starch test, the green leaf portion turns blue, indicating starch presence, confirming photosynthesis due to chlorophyll. Non-green parts lack chlorophyll, don't photosynthesize, and show no starch-related colour change.

Question 8(i)

Define the term Mutation.

Answer

Mutation is a sudden change in one or more genes, or in the number or in the structure of chromosomes.

Question 8(ii)

A pure breeding red flower variety of pea plant (RR) is crossed with a pure breeding white flower variety of pea plant (rr). Draw a Punnett square to find out the Phenotypic and Genotypic ratios of the progeny belonging to the F₂ generation.

Answer

Phenotypic Ratio: 3:1
RR,Rr will be red flowering and rr will be white flowering plant.

Genotypic Ratio: 1:2:1
RR(Dominant homozygous), Rr (Dominant heterozygous), rr(Recessive homozygous)

Question 8(iii)

Leaves of certain plants roll up on a hot sunny day. Explain by giving suitable reasons.

Answer

On a bright sunny day, the rate of transpiration is much higher than any other days. The leaves of certain plants roll up on a bright sunny day to reduce the exposed surface and thus reduce the rate of transpiration.

Question 8(iv)

What is a semi permeable membrane? Name the semi permeable membrane present in a plant cell.

Answer

A semipermeable membrane is a membrane which allows the passage of molecules selectively. It allows a solvent such as water molecules to pass through it freely but prevents the passage of the solute (sugar or salt molecules in solution).

Cell membrane is the semi permeable membrane present in the plant cell.

Question 8(v)

The diagram below depicts the human heart in one of its phases.

Answer the questions that follow:

(a) Which part of the heart is in the contraction phase?

(b) Give a suitable reason to justify your answer in (a).

(c) Distinguish between Systole and Diastole.

Answer

(a) Ventricles are in contraction phase

(b) Blood is passing into aorta and pulmonary artery through semilunar valves.

(c) Difference between Systole and Diastole: