Solved Sample Paper 2

Section A

Question 1(i)

Which one of the following is mainly concerned with motor signalling?

1. Hypothalamus
2. Spinal cord
3. Thalamus
4. Pons

Answer

Spinal cord

Reason — Spinal cord conducts motor responses from the brain to muscles of the trunk and limbs.

Question 1(ii)

Which of the following hormones promotes lateral bud development in dicots?

1. Auxin
2. Cytokinin
3. Gibberellins
4. Ethylene

Answer

Cytokinin

Reason — Cytokinin inhibits apical dominance and promotes lateral bud development.

Question 1(iii)

The gap between the neurons is called

1. axon
2. internode
3. synapse
4. dendrite

Answer

synapse

Reason — Synapse is the point of contact between the terminal branches of axon with the dendrites of another neuron separated by a fine gap.

Question 1(iv)

Which part of the brain mainly controls body temperature?

1. Thalamus
2. Hypothalamus
3. Cerebrum
4. Cerebellum

Answer

Hypothalamus

Reason — Hypothalamus controls body temperature.

Question 1(v)

Leaf fall can be induced by

1. cytokinins
2. auxin
3. abscisic acid
4. ethylene

Answer

abscisic acid

Reason — Abscisic acid accelerates ageing and abscission of leaves.

Question 1(vi)

Assertion(A): Loss of water as tiny drops along the margins of the tips of leaves, especially in the early morning is called guttation.

Reason: Excessive root pressure is responsible for guttation.

1. Both A and R are true
2. Both A and R are false
3. Ais true and R is false
4. A is false and R is true

Answer

Both A and R are true

Reason — Guttation is loss of water as tiny drops from hydathodes of leaves. It occurs due to high root pressure.

Question 1(vii)

Which one of the following does not affect the rate of transpiration?

1. Light
2. Wind
3. Age of the plant
4. Humidity

Answer

Age of the plant

Reason — Transpiration is affected by light intensity, wind and humidity. Age of plant is not related to rate of transpiration.

Question 1(viii)

The declining phase of a population occurs when

1. Mortality > Natality
2. Natality > Mortality
3. Mortality = Natality
4. Natality = Mortality = 0

Answer

Mortality > Natality

Reason — When death rate (mortality) is higher than birth rate (Natality), there is decrease in population.

Question 1(ix)

Harish was fond of eating dryfruits. He put some raisins in the water for 5-6 hours. After few hours, the raisins were all swelled up. This was due to

1. endosmosis
2. exosmosis
3. osmoregulation
4. no osmosis

Answer

endosmosis

Reason — When raisins are placed in water (hypotonic), endosmosis occurs. Hence, they absorb water and swell up.

Question 1(x)

Acid rain is caused by a

1. SO₂, SO₃
2. SO₂, CO
3. CO, NH₃
4. SO₂, NO₂

Answer

SO₂, NO₂

Reason — SO₂ combines with water to form sulphuric acid and NO₂ combines with water to form nitric acid.

Question(xi)

Why should we conserve forests and wildlife?

1. To maintain balance
2. To protect biodiversity
3. To continue food chain
4. All of the above

Answer

All of the above

Reason — Conservation of forests and wildlife is done to maintain ecological balance by maintaining normal food chain and to protect biodiversity.

Question(xii)

Which of these is not a vestigial organ in human beings?

1. Appendix
2. Wisdom tooth
3. Gall bladder
4. Nictitating membrane

Answer

Gall bladder

Reason — Gall bladder is not a vestigial organ as it stores bile which is produced by liver.

Question(xiii)

Blood flows in arteries in spurts and is under pressure. Which of the following reasons support this statement?

P. Arteries transport blood from left ventricles.

Q. Blood in left ventricle is at a high pressure.

R. Arteries have valves.

1. Only P
2. Only Q
3. Only P and Q
4. Only P and R

Answer

Only P and Q

Reason — Left ventricle pumps oxygenated blood at a high pressure to the rest of the body through arteries. This high-pressure blood is what causes the blood in the arteries to flow in a pulsatile manner, resulting in spurts.
Statement R, "Arteries have valves," is not relevant to the blood flow in arteries. Valves are typically found in veins to prevent the backflow of blood, not in arteries.

Question(xiv)

The liquid which collects in the cavity of Bowman's capsule is

1. concentrated urine
2. blood plasma minus blood proteins
3. glycogen and water
4. used bile for excretion

Answer

blood plasma minus blood proteins

Reason — During ultrafiltration almost all the liquid part of the blood i.e plasma and organic/inorganic substances are collected in Bowman's capsule.

Question (xv)

The water absorbed by the root is carried through the stem to all parts of the plant.

Which of the following is/are involved in the process described above?

(1) Xylem (2) Phloem (3) Hydathodes (4) Guard cells

1. Only 1
2. Only 1, 2 and 3
3. Only 2 and 3
4. Only 1, 3 and 4

Answer

Only 1

Reason — The transportation of water in plants is done by xylem vessel.

Question 2(i)

Name the following.

(a) The instrument which is used to measure water uptake by the plant shoot during transpiration.

(b) Movement of substances into root cells without the expenditure of energy.

(c) The enzyme that is released from the injured cells and blood platelets of a wound.

(d) The hormone produced when a plant is exposed to stress.

(e) The part of the internal ear concerned with dynamic equilibrium of the body.

Answer

(a) Potometer

(b) Passive transport

(c) Thrombokinase

(d) Abscisic Acid

(e) Sensory cells in Semicircular canal

Question 2(ii)

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

(a) Cell wall, Nucleus, Nucleoplasm, Cell membrane, Cytoplasm

(b) Australopithecus, Homo erectus, Cro-Magnon, Homo habilis, Homo sapiens sapiens

(c) Head, Pulmonary artery, Right ventricle, Right auricle, Superior vena cava

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

(e) Gamete formation, Zygote, Fertilisation, Embryo

Answer

(a) Cell wall, Cell membrane, Cytoplasm, Nucleus, Nucleoplasm,

(b) Australopithecus, Homo habilis, Homo erectus, Cro-Magnon, Homo sapiens sapiens

(c) Head, Superior vena cava, Right auricle, Right ventricle, Pulmonary artery.

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

(e) Gamete formation, Fertilisation, Zygote, Embryo

Question 2(iii)

Fill in the blanks with suitable words.

The heart consists of four chambers (a) ............... and two (b) ............... . The atria have (c) ............... walls. The ventricles have (d) ............... walls. The right ventricle pumps blood only up to the (e) ............... for oxygenation.

Answer

The heart consists of four chambers (a) two atria and two (b) ventricles . The atria have (c) thin walls. The ventricles have (d) thick muscular walls. The right ventricle pumps blood only up to the (e) lungs for oxygenation.

Question 2(iv)

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

(a) Cortisol, Calcitonin, Cytokinin, Insulin

(b) CO₂, NO₂, SO₂, NH₃

(c) Law of dominance, Law of segregation, Law of Linkage, Law of independent assortment

(d) Ovary, Fallopian tube, Ureter, Uterus

(e) 'A' blood group, 'B' blood group, 'O' blood group, 'AB' blood group

Answer

(a) Odd one: Cytokinin
Category: Others are human hormones.

(b) Odd one: NH₃
Category: Others are the type of vehicular air pollutants.

(c) Odd one: Law of Linkage
Category: Others are Mendel's laws.

(d) Odd one: Ureter
Category: Others are parts of female reproductive system

(e) Odd one: 'O' blood group
Category: Others have antigen present on RBC in all blood groups.

Question 2(v)

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

Answer

Section B

Question 3(i)

Substances which are made up of cellulose or proteins are hydrophilic. What will happen to the wooden doors in rainy season?

Answer

The wooden doors will swell up during rainy season by absorbing moisture present in the air as cellulose being hydrophilic will imbibe (surface attraction) water.

Question 3(ii)

What is apical dominance? Name the hormone that controls it.

Answer

The phenomenon of the suppression of growth of lateral buds by apical buds is called apical dominance. It is controlled by auxin.

Question 3(iii)

Give differences between active transport and osmosis.

Answer

Question 3(iv)

What is sex-linked inheritance? Give one example.

Answer

Inheritance of any character whose gene are present on sex chromosomes (either X or Y) is called sex linked inheritance. For example : Hemophilia is X-linked genetic disorder.

Question 3(v)

Draw a clear diagram of human kidney and label following parts on it, renal capsule, cortex, hilum and ureter.

Answer

Diagram of human kidney with renal capsule, cortex, hilum and ureter labelled is shown below:

Question 4(i)

Mention the exact location of dark reaction.

Answer

Dark reaction occurs in stroma.

Question 4(ii)

Mention two reasons for the increase of population in India.

Answer

Two reasons for the increase of population in India are:

1. Illiteracy — Most of the rural population which forms the bulk of our society is still illiterate, ignorant and superstitious. They also do not know the functioning of the human reproductive system.
2. Traditional Beliefs — Among the people from lower strata of the society, children are regarded as a gift of God and a sign of prosperity. Therefore, they make no effort to avoid pregnancy.

Question 4(iii)

Differentiate between haemophilia and colour blindness.

Answer

Differences between haemophilia and colour blindness are:

Question 4(iv)

What is the function of coronary arteries? What will be their affect on human if they get blocked?

Answer

Coronary arteries supply blood to the heart muscles. When there is a blockage in any coronary artery or in any one or more of their branches, there is deadening of the corresponding area of heart muscles leading to myocardial infarction commonly referred to as a heart attack.

Question 4(v)

Draw a neat and labelled diagram to show hypermetropia.

Answer

Below labelled diagram shows hypermetropia:

Question 5(i)

Define sewage.

Answer

Sewage is the liquid waste from domestic activities. It contains kitchen wastes, toilet and other household waste water.

Question 5(ii)

Enlist some of the consequences of population explosion.

Answer

Some of the consequences of population explosion are:

1. Unemployment — Population explosion leads to unemployment as sufficient numbers of jobs are not available for the growing population.
2. Increased Pollution — Due to population explosion, all kinds of pollutions (land, air, soil and water) increase causing degradation of environment and climatic conditions.

Question 5(iii)

Two potted plants are fixed horizontally in clinostat. One is rotated and the other is not. What will be your observation after some time?

Answer

After sometime we can observe that the static potted plant will show positive geotropism in root and negative geotropism in shoot. The rotating plant will not show any bending. It is because gravitational force was equally applied to all its part.

Question 5(iv)

Fixing of the embryo in the wall of uterus is A. Time taken by an embryo for full development in B. Name A and B.

Answer

A → Implantation

B → Gestation

Question 5(v)

The diagram given below is a representation of K⁺ transport mechanism of stomatal opening and closing. Study the same and answer the questions that follows:

(a) Name the cell labelled as A.

(b) Mention the states of guard cells represented by B and C.

(c) What causes closure of stomata during night?

Answer

(a) A represents epidermal cells.

(b) The state of guard cell represented by B is turgid and the state of guard cell represented by C is flaccid.

(c) During day, the guard cells have high concentration of K⁺ making it hypertonic. During night, the K⁺ ions are transported to epidermal cells due to which there is loss of water from guard cells making them flaccid. The stomata closes when guard cells are flaccid.

Question 6(i)

Give the exact location of pituitary gland.

Answer

Pituitary gland is located at the base of the midbrain below the hypothalamus.

Question 6(ii)

Differentiate between metaphase and anaphase.

Answer

Differences between between metaphase and anaphase are:

Question 6(iii)

A trait may be inherited but may not be expressed. Explain.

Answer

A dominant allele expresses itself while the recessive allele is masked in heterozygous condition. For example, when a plant with round (RR) seeds is crossed with a plant with wrinkled (rr) seeds, all F₁ plants are with round seeds. Here, the genes are in heterozygous condition i.e., Rr. Allele 'r' is present but is not expressed as its effect is masked by allele 'R'. Therefore, we can say that a trait may be inherited but may not be expressed.

Question 6(iv)

State the functions of pons and cerebellum.

Answer

Function of pons:

1. Carries impulse from one hemisphere of cerebellum to other hemisphere.
2. Coordinates muscular movements on both the sides of the body.

Function of cerebellum :

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

Question 6(v)

Study the given diagram and answer the questions that follows.

(a) Name the parts labelled A, B and C in the diagram.

(b) State the function of part labelled A and B.

(c) Name the audio receptor region present in the part labelled A.

Answer

(a) The parts labelled A, B and C are:

• A → Cochlea
• B → Semi-circular canals
• C → Ear ossicles

(b)

• A → helps in hearing whereas
• B → helps in maintaining dynamic balance.

(c) Organ of Corti

Question 7(i)

Expand the abbreviation TSH.

Answer

Thyroid Simulating Hormone

Question 7(ii)

State the function of epididymis.

Answer

The epididymis stores the sperms for some days during which they mature and become motile (capable of moving).

Question 7(iii)

Give differences between turgidity and flaccidity.

Answer

Differences between turgidity and flaccidity are:

Question 7(iv)

Explain why generally only the male child suffers from colour blindness and not the female?

Answer

Colour blindness is an X-linked recessive genetic disorder caused by mutations in genes located on the X chromosome. Since females typically inherit two X chromosomes, the chance of both X chromosomes carrying the recessive mutation is indeed rare. Therefore, the likelihood of a female developing colour blindness is extremely low.

Question 7(v)

The given figure shows a cell. Study the figure and answer the questions that follows.

(a) Identify the stage of cell cycle depicted by the cell.

(b) Write any two characteristic of this phase.

(c) Identify A and B.

Answer

(a) Interphase

(b) This phase of the cell is characterised by:

1. growth in cell size
2. duplication of chromatin material.

(c) A and B are:

• A → Centrosome
• B → Chromatin threads

Question 8(i)

Define dialysis.

Answer

The artificial method of filtering out the excretory product from the body when both the kidney of a person fails to do so either due to injury or disorder is called dialysis.

Question 8(ii)

Name two types of passive transport.

Answer

Two types of passive transport are:

1. Diffusion
2. Osmosis

Question 8(iii)

Which gland secretes thyroxine? What will happen if the secretion of thyroxine is insufficient?

Answer

Thyroid gland secretes thyroxine. Insufficient secretion of thyroxine is called hypothyroidism. It may leads to simple goitre, cretinism and myxoedema.

Question 8(iv)

State two functions of placenta.

Answer

Two functions of placenta are:

1. Acts as a barrier and prevents germs from entering foetal blood.
2. Enables exchange of respiratory gases, nutrients and removes waste products of the foetus.

Question 8(v)

The diagram below represents an experiment to demonstrate a particular aspect of a physiological process in plants. Study the diagram and answer the questions that follows.

(a) What is the aim of the experiment?

(b) What is the chemical substance named X in the diagram? What will be the effect of treatment with the solution of substance X?

(c) Out of the parts mentioned A and B, which will show blue-black colour in the presence of X. Why?

Answer

(a) The aim of the experiment is to show that sunlight is necessary for photosynthesis.

(b) The chemical substance named X in the diagram is iodine. After treatment with iodine solution, the part of the leaf, which contains starch will show blue-black colour. The part having no starch will turn brown.

(c) The portion A will show blue black colour because it received sunlight and starch was formed as a result of photosynthesis.