Solved Sample Paper 4

Section A

Question 1(i)

Adrenaline is a 'stress hormone' found in humans similarly the 'stress hormone' of plant is

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

Answer

abscisic acid

Reason — Abscisic acid is the plant hormone that helps the plant to survive in unfavourable conditions. They cause closure of stomata and also inhibit growth.

Question 1(ii)

Area of best vision and contains maximum cone cells

1. Blind spot
2. Red spot
3. Blue spot
4. Yellow spot

Answer

Yellow spot

Reason — Yellow spot or macula lutea is the spot with maximum number of sensory cells and particularly cone cells.

Question 1(iii)

Chlorophyll is required in leaves for

1. splitting of water in hydrogen and oxygen
2. trapping sunlight
3. storing food
4. emitting light

Answer

trapping sunlight

Reason — The function of chlorophyll is to trap photons. This provides energy for splitting of water molecule.

Question 1(iv)

The first heart sound (Lubb) is produced due to

1. closure of tricuspid and bicuspid valves
2. closure of aortic and pulmonary valves
3. rushing of blood through valves producing turbulence
4. entry of blood into auricles

Answer

closure of tricuspid and bicuspid valves

Reason — Tricuspid and bicuspid valves get closed sharply at the start of ventricular systole.

Question 1(v)

The accidental discharges of petroleum in oceans or estuaries are

1. industrial waste
2. oil spills
3. oil waste
4. liquid spills

Answer

oil spills

Reason — Accidental discharges of petroleum in oceans or estuaries are termed "oil spills"

Question 1(vi)

Assertion (A) An average adult have about 5-6 litres of blood by volume in his body.

Reason (R) The main functions of the blood in our body are transportation and protection.

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

Answer

Both A and R are true

Reason — An average adult has 5-6 litres of blood by volume in his body. The main functions of the blood are transportation and protection.

Question 1(vii)

Main reason for sharp rise in world human population in the recent past

1. Poor health care
2. Improved nutrition
3. More deaths
4. Small scale immunisation

Answer

Improved nutrition

Reason — Improved nutrition has led to better health and hence decreased mortality.

Question 1(viii)

In human females, 23rd pair of chromosome is

1. XY
2. XX
3. Both XX and XY
4. Neither XX or XY

Answer

XX

Reason — In human females, 22 pairs of chromosome are autosome and 23rd pair of chromosome is sex chromosome i.e XX. In males, it is XY.

Question 1(ix)

Which of the following blood vessels is comprised of thick walls and narrow central lumen?

1. Vein
2. Venule
3. Artery
4. Capillary

Answer

Artery

Reason — This is because, they have to withstand pressure of the blood.

Question 1(x)

Maximum amount of water from the glomerular filtrate is reabsorbed in

1. PCT
2. descending limbs of loop of Henle
3. ascending limbs of loop of Henle
4. DCT

Answer

PCT

Reason — About two-third water is reabsorbed in PCT.

Question 1(xi)

Harish went to the beach for vacation of 2-3 days. After coming home he noticed his skin tone has darkened. This was due to

1. melanin
2. rhodopsin
3. thyroxine
4. serotonin

Answer

melanin

Reason — The darkening of Harish's skin tone after a beach vacation is primarily due to the increased production of melanin, a pigment responsible for skin color.

Question 1(xii)

Maximum transpiration in plant takes place from

1. stomata
2. cuticles
3. lenticels
4. root hairs

Answer

stomata

Reason — Stomata are responsible for maximum amount of transpiration.

Question 1(xiii)

Injury to the medulla generally results in death. Which of the following reasons support this statement?

P. It controls the activities of the internal organs.

Q. It control involuntary actions like salivation, vomiting, movement of breathing, beating of the heart.

R. It is the main thinking part of the brain.

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

Answer

Only P and Q

Reason — Injury to the medulla can lead to death due to its control over vital functions like internal organ activities and involuntary actions, but it is not the main thinking part of the brain.

Question 1(xiv)

The external female genitalia is called the

1. hymen
2. uterus
3. vagina
4. vulva

Answer

vulva

Reason — The external female genitalia is called the vulva.

Question 1(xv)

After coming from school, Rita wants to watch some programme on TV. She switch it on and press the remote for a particular channel.

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

(a) Cerebrum
(b) Cerebellum
(c) Skeletal muscles
(d) Medulla oblongata

1. Only c
2. Only a and c
3. Only c and d
4. Only b, c and d

Answer

Only a and c

Reason — Rita's act of switching channels involves the cerebrum for decision-making and skeletal muscles for pressing the remote

Question 2(i)

Name the following.

(a) General name of chemical substances which bring about control and coordination in plants.

(b) The kind of lens required to correct myopia.

(c) The prime source of chlorofluorocarbon is

(d) The chromatin material is formed of

(e) A pollutant which is mainly responsible for causing acid rain.

Answer

(a) Phytohormone

(b) Concave lens

(c) Refrigerant

(d) DNA and histone protein

(e) Sulphur dioxide (SO₂)

Question 2(ii)

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

(a) Ureter, Kidney, Renal artery, Urinary bladder

(b) Intestine, Intestinal artery, Hepatic portal vein, Liver

(c) Right auricle, Pulmonary artery, Vena cava, Right ventricle

(d) Sperm duct, Sperm, Vagina, Urethra, Coitus.

(e) Fertilisation, Gamete formation, Embryo, Zygote.

Answer

(a) Renal artery, Kidney, Ureter, Urinary bladder.

(b) Intestinal artery, Intestine, Hepatic portal vein, Liver

(c) Vena cava, Right auricle, Right ventricle, Pulmonary artery

(d) Sperm, Sperm duct, Urethra, Coitus, Vagina

(e) Gamete formation, Fertilisation, Zygote, Embryo

Question 2(iii)

Fill in the blanks with suitable words.

The loss of excess water in the form of drops along the (a) ............... due to excessive (b) ............... is called guttation. In certain plants, like (c) ............... , grass etc. the root pressure is high enough to force the water all the way through the (d) ............... and comes out through the ends of (e) ............... .

Answer

The loss of excess water in the form of drops along the (a) leaf margins due to excessive (b) root pressure is called guttation. In certain plants, like (c) banana , grass etc. the root pressure is high enough to force the water all the way through the (d) stem and comes out through the ends of (e) leaf veins .

Question 2(iv)

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

(a) Genotype, Phenotype, Allotype, Mutation

(b) White matter, Duramater, Arachnoid matter, Piamater

(c) Addison's disease, Cushing's syndrome, Adrenal virilism, Cretinism.

(d) Mining, Stone drilling, Wearing of rubber tyres, Noise of jet

(e) Cortisol, Aldosterone, Androgen, Epinephrine

Answer

(a) Odd one: Allotype
Category: Others are genetic terms

(b) Odd one: White matter
Category: Others are layers of meninges

(c) Odd one: Cretinism
Category: Others are abnormalities related with adrenal cortex hormones.

(d) Odd one: Noise of jet
Category: Others are causes of particulate pollution

(e) Odd one: Epinephrine
Category: Others are hormones of adrenal cortex.

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)

When a black coloured guinea pig is crossed with a white coloured guinea pig. What coloured obtained in F₁ generation if black colour is dominant over white?

Answer

F₁ generation will be black colour.

Question 3(ii)

Mention 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 3(iii)

What are differences between allosomes and autosomes?

Answer

Question 3(iv)

There is a need to check over-exploitation of resources. Explain.

Answer

The increasing human population is exerting pressure on limited resources essential for human growth, development, and well-being, necessitating a thorough examination of resource over-exploitation and its impact on ecological balance.

Question 3(v)

Draw a neat and labelled diagram showing the cross-section of an adrenal gland.

Answer

Below diagram shows the cross-section of an adrenal gland:

Question 4(i)

Mention the exact location of chordae tendinae.

Answer

Chordae tendinae connects papillary muscle to bicuspid and tricuspid valves in heart.

Question 4(ii)

Give two control measures of noise pollution.

Answer

Two control measures of noise pollution are:

1. Use of sound absorbent material.
2. Follow the norms of permissable sound.

Question 4(iii)

Explain systemic circulation.

Answer

It involves circulation of blood between the heart and the body organs (except lungs). It carries oxygenated blood to the body organs and returns deoxygenated blood back to the heart.

Question 4(iv)

Differentiate between embryo and foetus.

Answer

Question 4(v)

Draw a well labelled diagram of TS of artery and vein.

Answer

Below diagram shows the transverse section of artery and vein:

Question 5(i)

Define alleles.

Answer

Alternative forms of a gene are called allele.

Question 5(ii)

After examining a prepared slide under high power microscope, a student concludes that the given slide shows stage of mitosis. Write his observation on the basis of which this conclusion can be drawn.

Answer

He might have observed the following:

1. Formation of two cells from a cell.
2. Chromosomes attached to spindle fibre and are arranged in a plane at equator.
3. Splitting of sister chromatids in anaphase.

Question 5(iii)

Explain Darwin theory of 'Natural selection'.

Answer

During the struggle for existence, only those individuals which have advantageous variations survive while the ones which lack these variations are wiped out. Nature selects only those variations which are suitable for existence. This process is called natural selection.

Question 5(iv)

'A' forms the outer portion of the kidney and 'B' form the inner portion of the kidney. Name A and B.

Answer

• A → Cortex
• B → Medulla

Question 5(v)

Study the diagram given below and answer the questions that follows.

(a) Name the parts labelled 1, 2 and 3 in the diagram.

(b) Mention the collective terms for the membranes covering the brain.

(c) What is the function of cerebrospinal fluid?

Answer

(a)

• A → Cerebrum
• B → Cerebellum
• C → Medulla oblongata

(b) Meninges

(C) The cerebrospinal fluid provides nutrition and protection against jerk to the brain.

Question 6(i)

Given the exact location of interstitial cells.

Answer

Interstitial cells are present in seminiferous tubules.

Question 6(ii)

Give differences between passive transport and active transport.

Answer

Question 6(iii)

What is hydrotropism? Give one example.

Answer

The movement of plants in response to water is called hydrotropism. For example, roots move towards water.

Question 6(iv)

Make a Punnett square for finding out the proportion of different genotypes in the progeny of a genetic cross between a pure tall (TT) pea plant with a pure dwarf (tt) pea plant.

Answer

In F₁ generation:

All plants will be heterozygous tall.

In F₂ generation:

Genotypic ratio will be: 1 : 2 : 1

Question 6(v)

An outline sketch of a tree is shown in a diagram below. Study the same and answer the questions that follows.

(a) Name the phenomenon labelled A in diagram.

(b) Explain phenomenon 'A'.

(c) Give one significance of phenomenon 'A'.

Answer

(a) Transpiration

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

(c) Transpiration maintains the temperature of the plant.

Question 7(i)

Expand TSH.

Answer

TSH — Thyroid Stimulating Hormone

Question 7(ii)

Briefly explain the diencephalon.

Answer

Diencephalon is a part of fore brain. It has two parts:

1. Thalamus: It relays pain and pressure impulses to cerebrum.
2. Hypothalamus: It controls the body temperature and pituitary gland.

Question 7(iii)

What are main objectives of family welfare programme?

Answer

The main objectives of family welfare are:

1. Family planning in terms of having a small family.
2. Total welfare of the small family, including the diet and nutrition of the child and pregnant mother.
3. Subsequent care of the children, like immunisation and oral rehydration therapy, to ensure survival of the young ones

Question 7(iv)

Give difference between transpiration and guttation.

Answer

Question 7(v)

The diagram given below shows a type of tropism. Answer the questions that follows.

(a) What do A and B indicate?

(b) Name the tropic movements shown by parts A and B.

(c) Why do A and B show these types of movement?

Answer

(a)

• A → roots growing towards earth's gravity
• B → stem growing towards light

(b)

• A → geotropism
• B → phototropism

(c) Roots exhibit positive geotropic movement as they seek to absorb water and minerals from the soil. In contrast, shoots display negative geotropic movement, aiming to grow upward towards sunlight to facilitate photosynthesis in the leaves.

Question 8(i)

Define corpus callosum.

Answer

Corpus callosum ("hard body") is a sheet of fibres connecting the two cerebral hemispheres. It is located in the forebrain. It connects two cerebral hemispheres and transfers information from one hemisphere to other.

Question 8(ii)

Name the two genetic disorders in males caused due to sex-linked inheritance.

Answer

Colour blindness, Haemophilia

Question 8(iii)

State two harmful effects of soil pollution.

Answer

Two harmful effects of soil pollution are:

1. The pesticides used in agricultural farming may cause health problems.
2. The toxic industrial waste converts the fertile land into barren area.

Question 8(iv)

Rate of photosynthesis is low at very high temperature. Mention reason.

Answer

Rate of photosynthesis is low at very high temperature because enzymes responsible for photosynthesis get denatured at high temperature.

Question 8(v)

Given below is a diagram representing a stage during the mitotic cell division. Answer the following questions.

(a) Identify the stage.

(b) Give suitable reason for your answer in (a).

(c) What changes are observed with chromosomes during stage shown in diagram?

Answer

(a) Metaphase

(b) Metaphase stage is characterized by chromosomes arranged at equatorial plane.

(c) Spindle fibres attach to the centromere of each chromosome.