Biology 2012 Solved Paper Previous Year Question ICSE
(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. 
(a) (i) Transpiration.
(ii) Two cobalt chloride papers are attatched, one on the dorsal and the other on the ventral surface of a dorsiventral leaf with the help of glass slide and clips. The set up is left in the open for few hours.
(iii) To show that more transpiration occurs from the ventral surface of a dicot leaf.
(iv) After an hour, the cobalt chloride paper placed on the ventral surface turns blue to pink faster than the one on the upper surface.
Because no. of stomata are more on the ventral surface, so more transpiration takes place from the lower surface.
(v) 1. Cuticle becomes thick.
2. Leaves becomes narrow.
3. Stomata covered by hair like structures.
(b) (i) Selectively permeable membrane
(ii) Recessive character
(iii) Optic nerve
(vii) Tropic Hormones
(viii) Luteal phase
(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 icondition of the cell given above ?
(ii) Give the technical term for the solution in which the ceil 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 ? 
(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). 
(a) (i) Plasmolysed
(ii) Hypertonic solution
(iii) (1) Nucleus (2) Chloroplast (3) Vacuole (4) Hypertonic solution
(iv) Plant cell. Because
(1) Clear distinct cell wall is seen
(2) Chloroplast clearly seen in. the cytoplasm.
(3) Centrosome not seen.
(v) Place it on a hypotonic medium or plain water for some time.
(b) (i) Natality – Number of live births per 1000 per year.
Mortality – Number of deaths per 1000 per year.
(ii) Stoma – The opening in the stomata through which transpired water and respiratory gases pass.
Stroma – It is the part/region in the chloroplast where dark reaction of photosynthesis takes place.
(iii) Acromegaly – Overgrowth of certain parts of body like cheek bones etc. due to oversecretion of growth hormone in adults.
Cretinism – Dwarfism and mental retardation due to undersecretion of thyroxine in children.
(iv) Transpiration – Stomata/cuticle/lenticels.
Guttation – Hydathodes.
(v) Diabetes mellitus – Undersecretion of insulin due to which level of glucose increases in blood.
Diabetes insipidus – Undersecretion of Antidiuretic hormone due to which reabsorption of water from kidney tubules becomes less.
(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. 
(b) Briefly explain the following :
(i) Osmosis (ii) Allele (iii) Pulse (iv) Reflex action (v) Synapse 
(a) (i) 1—Posterior Vena Cava
(ii) Part 5 : Ureter – Carry urine from kidneys to urinary bladder.
Part 6 : Urinary bladder – Contain the urine till it is released out.
Part 7: Sphincter muscles – Guards the urethra
Part 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.
(b) (i) Osmosis : The process of movement of solvent molecules from a region of low concentration to a region of higher concentration through a semipermeable membrane.
(ii) Allele – It is one of the alternative form of the same gene responsible for determining contrasting characteristics.
(iii) Pulse – It is a wave of pressure of blood passing through the arteries as it is pumped out of the heart.
(iv) Reflex Action : It is a spontaneous, automatic, involuntary response to a stimulus.
(v) Synapse : It is the point of contact between the axon endings of one neuron with the dendrites of the other neuron through where the impulse is transmitted from one neuron to the other.
(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 magnifi-cation and label the following parts.
(1) Acrosome (2) Mitochondria 
(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. 
(a) (i) A – Ovary: Two hormones are :
(1) Oesterogen (2) Progesteron
(ii) (1) If fertilisation takes place, part B i.e. uterus gets prepared to receieve the embryo. The endometrial lining thickens and gets highly vascularised.
(2) If fertilisation does not take place part B, then the endometrial lining of uterus erodes causing bleeding i.e., menstruation.
(iii) Fertilisation occurs in the fallopian tube/oviduct.
(b) (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.
(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
(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 exported result of the above test on the parts labelled A and B ?
(v) Give a balanced chemical equation to represent the process of Photosynthesis.
(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 ? Name the blood vessel that :
(iv) Name the blood vessel that:
(1) begins and ends in capillaries
(2) supplies blood to the walls of the heart 
(a) (i) To show that chlorophyll is necessary ku 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 blue black with Iodine solution.
Part B turns brown with Iodine solution Sunlight