Question 1

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]

Accepted 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 2

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.

Accepted 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 3

Question 1(g)Match the items in Column A with that which is most appropriate in Column B. Rewrite the matching pairs : [5]Column AColumn B(1) Potometer(a) Antiseptic(2) Hypothalamus(b) Disinfectants(3) Formalin(c) Vasectomy(4) Contraception in males(d) Sudden change in genes(5) Mutation(e) Pituitary gland (f) Tubectomy (g) Transpiration (h) Thyroid gland (i) Alleles (j) Photosynthesis

Accepted Answer

Column AColumn B(1) Potometer(g) Transpiration(2) Hypothalamus(e) Pituitary gland(3) Formalin(b) Disinfectants(4) Contraception in males(c) Vasectomy(5) Mutation(d) Sudden change in genes

Question 4

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]No.SetOdd oneCategoryeg:Cell wall, large vacuole, plastids, centrosomecentrosomeparts of plant cell.(i)Cerebrum, cerebellum, thalamus, hypothalamus(ii)Ovary, ureter, fallopian tube, uterus(iii)Adrenal gland, liver, thyroid gland, pituitary gland(iv)Malleus, Pinna, Incus, Stapes(v)Haemophilia, colour blindness, albinism, night blindness

Accepted Answer

No.SetOdd oneCategory(i)Cerebrum, cerebellum, thalamus, hypothalamusCerebellumParts of fore brain(ii)Ovary, ureter, fallopian tube, uterusUreterParts of female reproductive system(iii)Adrenal gland, liver, thyroid gland, pituitary glandLiverEndocrine glands(iv)Malleus, Pinna, Incus, StapesPinnaEar ossicles(v)Haemophilia, colour blindness, albinism, night blindnessnight blindnessSex-Linked Inheritance.

Question 5

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]

Accepted 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:Sunken stomataNarrow leavesReduced exposed surface by rolling or folding of leaves.

Question 6

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]

Accepted 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 7

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]

Accepted Answer

(i) Difference between Natality and Mortality (definition)NatalityMortalityThe total number of live births per 1000 people of population per year is called birth rate or natality.The total number of deaths per 1000 people of population per year is called death rate or mortality.(ii) Difference between Stoma and Stroma (describe its structure.)StomaStromaA stoma is a microscopic pore surrounded by two specialized guard cells found in the leaves and stems. Its main function is gaseous exchange.Stroma is the colourless ground substance found in the chloroplast. It is the site of the light independent reactions of photosynthesis.(iii) Difference between Acromegaly and Cretinism (symptoms)AcromegalyCretinismOvergrowth of certain parts of the body like cheek bones etc, due to oversecretion of growth hormone in adults.Dwarfism and mental retardation due to under secretion of thyroxine in children.(iv) Difference between Transpiration and Guttation (structures involved)TranspirationGuttationTranspiration occurs from Stomata/cuticle/lenticels.Guttation occurs from Hydathodes.(v) Difference between Diabetes mellitus and Diabetes insipidus (reason/cause)Diabetes mellitusDiabetes insipidusUndersecretion of insulin due to which level of glucose increases in blood.Undersecretion of Antidiuretic hormone due to which reabsorption of water from kidney tubules becomes less.

Question 8

Question 4(b)Briefly explain the following:(i) Osmosis(ii) Allele(iii) Pulse(iv) Reflex action(v) Synapse [5]

Accepted 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 9

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]

Accepted 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:6CO2+12H2O  ⟶chlorophylllight energy  C6H12O6+6H2O+6O2↑6CO_2 + 12H_2O \space \space \overset{	ext{light energy}}{\underset{	ext{chlorophyll}}{\longrightarrow}} \space \space C_6H_{12}O_6 + 6H_2O + 6O_2 \uparrow6CO2​+12H2​O  chlorophyll⟶​light energy​  C6​H12​O6​+6H2​O+6O2​↑

Question 10

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:begins and ends in capillariessupplies blood to the walls of the heart. [5]Answer(i) A → Artery, B → VeinA 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 → Endothelium2 → 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:Begins and ends in capillaries — "Hepatic portal Vein".Supplies blood to the walls of the Heart — "Coronary artery".

Accepted Answer

Answer: [5]

Question 11

Question 7(a)Answer the following:(i) Draw a well labelled diagram of a 'Neuron' and name the following partsNode of RanvierNissil granulesCyton(ii) Name the part of the human brain which is concerned with the following :Seat of memoryCoordinates muscular activity(iii) Mention any three major activities of the WHO. [5]

Accepted 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:Seat of Memory — Cerebrum.Co-ordinates muscular activity — Cerebellum.(iii) Three major activities of the WHO are:To collect and supply information about occurrence of epidemic diseases. Example — Cholera, Typhoid etc.To supply information on latest developments about the use of vaccines and about health hazards of nuclear radiation.To lay pharmaceutical standards for important drugs.

Question 12

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:Pituitary gland is also known as the master gland.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:Desire for a male child.Lack of awareness about birth control measures.(iii) Biological Reasons:Pituitary gland is popularly called as the master gland because it controls the functioning of all the other endocrine glands.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.

Accepted Answer

Answer: [5]

Solved 2012 Question Paper ICSE Class 10 Biology

Section I 40 Marks

Section Ii 40 Marks