Solved 2012 Question Paper ICSE Class 10 Biology

Section I (40 Marks)

Question 1(a)

Name the following:

(i) The phenomenon by which living or dead plant cells absorb water by surface attraction.

(ii) The phase of cardiac cycle in which the auricles contract.

(iii) The organ where urea is produced.

(iv) The hormone that helps increase the reabsorption of water from the kidney tubules.

(v) Chemical substances produced by micro organisms that can kill or inhibit the growth of other micro organisms. [5]

Answer

(i) Imbibition

(ii) Atrial systole

(iii) Liver

(iv) Antidiuretic hormone/Vasopressin

(v) Antibiotics

Question 1(b)

Choose the correct answer from the four options given below each statement:

(i) BCG vaccine is used to build immunity against :

1. Poliomyelitis
2. Tuberculosis
3. Malaria
4. Whooping cough

(ii) A plant is kept in a dark cupboard for about 48 hours before conducting any experiment on photosynthesis to :

1. Remove starch from the plant
2. Ensure that starch is not translocated from the leaves
3. Remove chlorophyll from the leaf of the plant
4. Remove starch from the experimental leaf

(iii) The part of the human eye where rod cells and cone cells are located is the :

1. Retina
2. Cornea
3. Choroid
4. Sclera

(iv) A reflex arc in man is best described as movement of stimuli from :

1. Receptor cell, sensory neuron, relaying neuron, effector muscles.
2. Receptor cell, efferent nerve, relaying neuron, muscles of the body
3. Receptor cell, spinal cord, motor neuron, relaying neuron.
4. Receptor cell, synapse, motor neuron, relaying neuron.

(v) NADP is expanded as :

1. Nicotinamide, adenosine dinucleostide phosphate
2. Nicotinamide, adenine dinucleotide phosphate
3. Nicotinamide, adenine dinucleous phosphate
4. Nicotinamide, adenosine dinucleous phosphate [5]

Answer

(i) Tuberculosis

(ii) Remove starch from the experimental leaf

(iii) Retina

(iv) Receptor cell, sensory neuron, relaying neuron, effector muscles

(v) Nicotinamide, adenine dinucleotide phosphate

Question 1(c)

State the main function of the following:

(i) Chordae tendinae

(ii) Lymphocytes

(iii) Seminiferous tubule

(iv) Thylakoids

(v) Beta cells of pancreas [5]

Answer

(i) Chordae tendineae play a vital role in holding the atrioventricular valves in place while the heart is pumping blood.

(ii) Lymphocytes produce antibodies which kill or neutralise the germs or the poisons from them.

(iii) The Seminiferous tubules produce sperms by the process called spermatogenesis.

(iv) The thylakoid membranes of a chloroplast are the site of light reactions of photosynthesis as the pigment chlorophyll is contained in the walls of thylakoids.

(v) Secrete insulin that helps to lower the level of glucose in blood.

Question 1(d)

Give the exact location of the:

(i) Lenticels

(ii) Prostate gland

(iii) Thyroid gland

(iv) Centrosome

(v) Mitral valve [5]

Answer

(i) Lenticels are located on the barks of the older woody stems.

(ii) Prostate gland is located between the urinary bladder and the point where sperm ducts join the urethra.

(iii) Thyroid is situated in the front part of the neck just below the larynx.

(iv) Centrosome is located in the cytoplasm usually close to the nucleus in animal cells.

(v) Mitral value is located between the left auricle and left ventricle.

Question 1(e)

Given below are sets of five terms each. In each case rewrite the terms in logical sequence as directed at the end of each statement. An example has been done for you:
Example : Cortical cells, Root hair, xylem, Soil water, endodermis (absorption of water by the plants)
Answer : Soil water, Root hair, cortical cells, endodermis, xylem.

(i) Active immunity, Antigen, Antibody, Bacteria, Lymphocytes (defence mechanism of the body).

(ii) Implantation, Parturition, Ovulation, Gestation, Fertilisation (stages leading to formation of foetus and birth).

(iii) Oval window, Tympanum, Cochlea, Auditory canal, Ear ossicles (path through which a vibration of sound is transferred in the human ear).

(iv) Karyokinesis, S-phase, Cytokinesis, G1-phase, G2-phase (cell cycle).

(v) Renal vein, Renal artery, Afferent arteriole, Efferent arteriole, Glomerulus (pathway of blood through glomerulus). [5]

Answer

(i) Active immunity, Bacteria, Antigen, Lymphocytes, Antibody.

(ii) Ovulation, Fertilisation, Implantation, Gestation, Parturition.

(iii) Auditory canal, Tympanum, Ear ossicles, Oval window, Cochlea.

(iv) G1-phase, S-phase, G2-phase, Karyokinesis, Cytokinesis.

(v) Renal artery, Afferent arteriole, Glomerulus, Efferent arteriole, Renal vein.

Question 1(f)

Study the following diagram carefully and then answer the questions that follow. The diagram is depicting a defect of the human eye:

(i) Identify the defect shown in the diagram.

(ii) Give two possible reasons for the above defect.

(iii) Draw a neat labelled diagram to show how the above defect can be rectified. [5]

Answer

(i) Hypermetropia

(ii) Two possible reasons for the above defect are:

1. The eye ball is too short from front to back.
2. The lens is too flat.

(iii) Below diagram shows the rectification of the defect:

Question 1(g)

Match the items in Column A with that which is most appropriate in Column B. Rewrite the matching pairs : [5]

Answer

Question 1(h)

Given below are six sets with four terms each. In each set a term is an odd one and cannot be grouped in the same category to which the other three belong. Identify the odd one in each set and name the category to which the remaining three belong. The first has been done for you as an example. [5]

Answer

Section II (40 Marks)

Question 2(a)

Given below is an experimental set up to demonstrate a particular process. Study the same and answer the questions that follow:

(i) Name the physiological process being studied.

(ii) Explain the process mentioned above.

(iii) What is the aim of the above experiment ?

(iv) What would you observe in the experimental set-up after an hour? Give a reason to support your answer.

(v) Mention any three adaptations found in plants to overcome the physiological process mentioned in (i) above. [5]

Answer

(i) Transpiration.

(ii) Pieces of dry cobalt chloride paper are attached to the two surfaces of the leaf and held in position by two glass slides on either side tied together by elastic bands or held by clips. The leaf remains attached to its own plant. The setup is left for an hour or so.

(iii) The aim of the experiment is to prove that more transpiration occurs from the under surface of a dicot leaf.

(iv) After an hour, the piece of paper which is facing the upper surface of the leaf either does not turn pink or turns pink very slowly in a much longer time than the one on the lower surface which turns pink much faster. This proves that more Transpiration takes place from the lower surface, which is on account of the numerous stomata found on it.

(v) Some plants have developed adaptations to reduce transpiration to cut down loss of water such as:

1. Sunken stomata
2. Narrow leaves
3. Reduced exposed surface by rolling or folding of leaves.

Question 2(b)

Give the biological/technical terms for the following:

(i) A membrane which allows the passage of molecules selectively.

(ii) The suppressed allele of a gene.

(iii) Structure that carries visual stimuli from retina to the brain.

(iv) WBCs squeeze through the walls of the capillaries into the tissue.

(v) Protective coverings located round the human brain and spinal cord.

(vi) Eye lens losing flexibility resulting in a kind of long sightedness in elderly people.

(vii) Hormones which stimulate other endocrine glands to produce their specific hormones.

(viii) The phase in the menstrual cycle in which the remnant of follicle in the ovary turns to Corpus luteum.

(ix) Statistical study of human population.

(x) Artificially introducing weakened germs or germ substance into the body for developing resistance to a particular disease. [5]

Answer

(i) Selectively permeable membrane

(ii) Recessive character

(iii) Optic nerve

(iv) Diapedesis

(v) Meninges

(vi) Presbyopia

(vii) Tropic Hormones

(viii) Luteal phase

(ix) Demography

(x) Vaccination

Question 3(a)

Given below is the diagram of a cell as seen under the microscope after having been placed in a solution:

(i) What is the technical term used for the state/condition of the cell given above ?

(ii) Give the technical term for the solution in which the cell was placed.

(iii) Name the parts numbered 1 to 4.

(iv) Is the cell given above a plant cell or an animal cell? Give two reasons in support of your answer as evident from the diagram.

(v) What would you do to bring this cell back to it original condition? [5]

Answer

(i) Plasmolysed

(ii) Hypertonic solution

(iii) The parts numbered 1 to 4 are:

• 1 → Nucleus
• 2 → Chloroplast
• 3 → Vacuole
• 4 → Hypertonic solution

(iv) Plant cell because of the following reasons:

1. Clear distinct cell wall is seen
2. Chloroplast clearly seen in the cytoplasm.
3. Centrosome not seen.

(v) Place it in a hypotonic medium or plain water for some time.

Question 3(b)

Differentiate between the following pairs on the basis of what is mentioned in brackets:

(i) Natality and Mortality (definition)

(ii) Stoma and Stroma (describe its structure)

(iii) Acromegaly and Cretinism (symptoms)

(iv) Transpiration and Guttation (structures involved)

(v) Diabetes mellitus and Diabetes insipidus (reason/cause) [5]

Answer

(i) Difference between Natality and Mortality (definition)

(ii) Difference between Stoma and Stroma (describe its structure.)

(iii) Difference between Acromegaly and Cretinism (symptoms)

(iv) Difference between Transpiration and Guttation (structures involved)

(v) Difference between Diabetes mellitus and Diabetes insipidus (reason/cause)

Question 4(a)

The diagram below shows the Excretory System of a Human being. Study the same and then answer the questions that follow :

(i) Name the parts labelled 1, 2, 3 and 4.

(ii) Give the main function of the parts labelled 5, 6, 7 and 8.

(iii) Name the endocrine gland which could be added in the diagram and state its location/position. [5]

Answer

(i) The parts labelled 1, 2, 3 and 4 are:

• 1 → Posterior Vena Cava
• 2 → Aorta
• 3 → Renal Artery
• 4 → Renal Vein

(ii) Main function of the parts labelled 5, 6, 7 and 8 are:

• 5 → Ureter — Carry urine from kidneys to urinary bladder.
• 6 → Urinary bladder — Contain the urine till it is released out.
• 7 → Sphincter muscles — Guards the opening of the bladder into the urethra and relaxes only at the time of urination.
• 8 → Urethra — Passage through which urine is given out of the body.

(iii) Adrenal gland. It is located above each kidney in the form of a cap.

Question 4(b)

Briefly explain the following:

(i) Osmosis

(ii) Allele

(iii) Pulse

(iv) Reflex action

(v) Synapse [5]

Answer

(i) Osmosis — Osmosis is the movement of water molecules from their region of higher concentration (dilute solution or with a lower solute concentration) to their region of lower concentration (concentrated solution or with a higher solute concentration) through a semi permeable membrane.

(ii) Allele — Allele is one of the alternative form of the same gene responsible for determining contrasting characteristics.

(iii) Pulse — Pulse is the alternate expansion and elastic recoil of the wall of the artery during ventricular systole.

(iv) Reflex Action — Reflex action is an automatic or quick or immediate involuntary action in the body brought about by a stimulus.

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

Question 5(a)

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

(i) Name the part labelled A. Name any two hormones produced by the part labelled A.

(ii) What happens to the part labelled B:

1. If fertilisation takes place?
2. If fertilisation does not take place?

(iii) Where does fertilisation occur?

(iv) Draw a neat diagram of the human sperm as seen under high magnification and label the following parts:

1. Acrosome
2. Mitochondria [5]

Answer

(i) The part labelled A is Ovary. Two hormones produced by it are:

1. Oestrogen
2. Progesterone

(ii) (1) If fertilisation takes place, part B i.e. the uterus gets prepared to receieve the embryo. The endometrial lining thickens and gets highly vascularised. (2) If fertilisation does not take place, the thickened lining of part B i.e. the uterus (endometrium) restarts shedding on the 28th day of the menstrual cycle. Finally it is discharged out along with the unfertilised ovum as the menstrual flow through the cervix and the vagina.

(iii) Fertilisation occurs in the fallopian tube/oviduct.

(iv) Below diagram shows the human sperm with Acrosome and Mitochondria labelled:

Question 5(b)

A homozygous plant having round (R) and yellow (Y) seed is crossed with homozygous plant having wrinkled (r) and green (y) seeds :

(i) Give the scientific name of the plant on which Mendel conducted his hybridization experiments.

(ii) Give the genotype of the F₁ generation.

(iii) Give the dihybrid phenotypic ratio and the phenotype of the offspring of the F₂ generation when two plants of the F₁ generation are crossed.

(iv) Name and state the law which explains the dihybrid ratio.

(v) Give the possible combinations of gametes that can be obtained from F₁ hybrid. [5]

Answer

(i) Pisum sativum

(ii) Genotype of the F₁ generation Rr Yy

(iii) Ratio of F₂ generation 9:3:3:1 Phenotypes of F₂ generation are:

1. Round and yellow
2. Round and green
3. Wrinkled and yellow
4. Wrinkled and green

(iv) Law of Independent Assortment. It states that when there are two pairs of contrasting characters, the distribution of the members of one pair into the gametes is independent of the distribution of the other pair.

(v) F₁ genotype: Rr Yy So possible gamete combinations are

1. RY = Round yellow
2. rY = Wrinkled yellow
3. Ry = Round green
4. ry = Wrinkled green

Question 6(a)

The diagram below is an experiment conducted to study a factor necessary for Photosynthesis. Observe the diagrams and then answer the following questions:

(i) What is the aim of the experiment?

(ii) Name the test performed on the leaf and the solution used for the test.

(iii) What type of leaf was used for the experiment? Give an example.

(iv) What is the expected result of the above test on the parts labelled A and B?

(v) Give a balanced chemical equation to represent the process of Photosynthesis. [5]

Answer

(i) To show that chlorophyll is necessary for photosynthesis.

(ii) Starch test. Solution used in Iodine solution.

(iii) Variegated leaf / Coleus leaf (leaf having non green and green regions).

(iv) After performing starch test, Part A turns brown whereas Part B turns blue black. This is because only Part B which was green had starch produced by photosynthesis due to the presence of chlorophyll. The result proves that chlorophyll is necessary for photosynthesis.

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

$6CO_2 + 12H_2O \space \space \overset{\text{light energy}}{\underset{\text{chlorophyll}}{\longrightarrow}} \space \space C_6H_{12}O_6 + 6H_2O + 6O_2 \uparrow$

Question 6(b)

The diagram given below show the cross section of two kinds of blood vessels:

(i) Identify the blood vessels A and B. In each case give a reason to support your answer.

(ii) Name the parts numbered 1 and 2.

(iii) When are the sound "LUBB" and "DUP" produced during a heartbeat?

(iv) Name the blood vessel that:

1. begins and ends in capillaries
2. supplies blood to the walls of the heart. [5]

Answer

(i) A → Artery, B → Vein
A has narrow lumen and thick muscular wall whereas B has wide lumen and thin muscular wall.

(ii) The parts numbered 1 and 2 are:

• 1 → Endothelium
• 2 → Lumen

(iii) The first sound "LUBB" is produced when the atrio-ventricular (tricuspid and bicuspid) valves get closed sharply at the start of ventricular systole. The second sound "DUP" is produced when at the beginning of ventricular diastole, the semilunar valves at the roots of aorta and pulmonary artery get closed.

(iv) Names of the respective blood vessels are given below:

1. Begins and ends in capillaries — "Hepatic portal Vein".
2. Supplies blood to the walls of the Heart — "Coronary artery".

Question 7(a)

Answer the following:

(i) Draw a well labelled diagram of a 'Neuron' and name the following parts

1. Node of Ranvier
2. Nissil granules
3. Cyton

(ii) Name the part of the human brain which is concerned with the following :

1. Seat of memory
2. Coordinates muscular activity

(iii) Mention any three major activities of the WHO. [5]

Answer

(i) Well labelled diagram of a Neuron with Node of Ranvier, Nissil granules and Cyton named is shown below:

(ii) The respective parts of the human brain are mentioned below:

1. Seat of Memory — Cerebrum.
2. Co-ordinates muscular activity — Cerebellum.

(iii) Three major activities of the WHO are:

1. To collect and supply information about occurrence of epidemic diseases. Example — Cholera, Typhoid etc.
2. To supply information on latest developments about the use of vaccines and about health hazards of nuclear radiation.
3. To lay pharmaceutical standards for important drugs.

Question 7(b)

(i) Draw a well labelled diagram to show the metaphase stage of Mitosis in an animal cell having four chromosomes.

(ii) Mention any two reasons for the population explosion in India.

(iii) Give biological reasons for the following:

1. Pituitary gland is also known as the master gland.
2. Gametes have a haploid number of chromosome. [5]

Answer

(i) Well labelled diagram showing the metaphase stage of Mitosis in an animal cell having four chromosomes is shown below:

(ii) Two reasons for the population explosion in India are:

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

(iii) Biological Reasons:

1. Pituitary gland is popularly called as the master gland because it controls the functioning of all the other endocrine glands.
2. Gametes are produced as a result of Meiosis during which the chromosome number is reduced to half and each daughter cell receives half the set of chromosomes.
   These gametes (egg and sperm) unite to form a zygote. If both of them were diploid, the zygote would have twice the number of normal chromosomes and the organism produced would be abnormal.