ICSE Class 10 Biology Board Exam Question Paper 2012 with Solutions

ICSE Class 10 Biology Board Exam Question Paper with Solutions

SECTION-I (40 Marks)
(Attempt all questions from this Section.)

Question 1

(a) Name the following: [5]
(i) The phenomenon by which living or dead plant cells absorb water by surface traction.
(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.

Answer:
(i) Imbibition
(ii) Auricular systole
(iii) Liver
(iv) Antidiuretic hormone/Vasopressin
(v) Antibiotics

Teacher's Note:
a) This question tests fundamental biological terminology across various topics like plant physiology, human physiology, and microbiology.
b) Students should ensure precise spelling and accurate definitions for each term, as slight variations can lead to incorrect answers.

(b) Choose the correct answer from the four options given below each statement: [5]
(i) BCG vaccine is used to build immunity against
(A) Poliomyelitis
(B) Tuberculosis
(C) Malaria
(D) Whooping cough
(ii) A plant is kept in a dark cupboard for about 48 hours before conducting any experiment on photosynthesis to:
(A) Remove starch from the plant
(B) Ensure that starch is not translocated from the leaves
(C) Remove chlorophyll from the leaf of the plant
(D) Remove starch from the experimental leaf
(iii) The part of the human eye where rod cells and cone cells are located is the
(A) Retina
(B) Cornea
(C) Choroid
(D) Sclera
(iv) A reflex arc in man is best described as movement of stimuli from
(A) Receptor cell, sensory neuron, relaying neuron, effector muscles.
(B) Receptor cell, efferent nerve, relaying neuron, muscles of the body
(C) Receptor cell, spinal cord, motor neuron, relaying neuron.
(D) Receptor cell, synapse, motor neuron, relaying neuron
(v) NADP is expanded as:
(A) Nicotinamide, adenosine dinucleostide phosphate
(B) Nicotinamide, adenine dinucleotide phosphate
(C) Nicotinamide, adenine dinucleous phosphate
(D) Nicotinamide, adenosine dinucleous phosphate

Answer:
(i) (B) Tuberculosis
(ii) (D) Remove starch from the experimental leaf
(iii) (A) Retina
(iv) (A) Receptor cell, sensory neuron, relaying neuron, effector muscles
(v) (B) Nicotinamide, adenine dinucleotide phosphate

Teacher's Note:
a) This section tests knowledge of common biological facts, experimental procedures, and anatomical structures.
b) For MCQs, students should carefully read all options before selecting the most accurate one, especially for definitions and sequences.

(c) State the main function of the following: [5]
(i) Chordae tendinae
(ii) Lymphocytes
(iii) Seminiferous tubule
(iv) Thylakoids
(v) Beta cells of pancreas

Answer:
(i) Chordae tendinae - Holds the valves in position.
(ii) Lymphocytes - Produce antibodies to defend the body against infection.
(iii) Seminiferous tubule - Produce sperms
(iv) Thylakoids - Chlorophyll is located on the wall of thylakoids so light reaction of photosynthesis begins here.
(v) Beta cells of pancreas - Secrete insulin that helps to lower the level of glucose in blood.

Teacher's Note:
a) This question requires students to recall the specific functions of various biological structures and cells.
b) It is crucial to provide concise and accurate functions, focusing on the primary role of each component.

(d) Give the exact location of the : [5]
(i) Lenticels
(ii) Prostate gland
(iii) Thyroid gland
(iv) Centrosome
(v) Mitral valve.

Answer:
(i) Lenticels - On the older stems
(ii) Prostate gland - Between the urinary bladder and the point where sperm ducts join the urethra.
(iii) Thyroid gland - In the front part in the neck
(iv) Centrosome - Above the nucleus in animal cells.
(v) Mitral valve - Between the left auricle and left ventricle.

Teacher's Note:
a) This question assesses knowledge of anatomical locations of various structures in plants and humans.
b) Students should be specific with locations, avoiding vague descriptions, and using correct anatomical terms.

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

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

Teacher's Note:
a) This question tests the understanding of sequential biological processes and pathways.
b) Students must know the correct order of events in processes like immune response, reproduction, hearing, cell cycle, and blood flow in the kidney.

(f) Study the following diagram carefully and then answer the questions that follow. The diagram is depicting a defect of the human eye :
[Figure: A diagram showing light rays from a distant object passing through a convex lens (representing the eye lens) and converging behind the retina. A second diagram shows a biconvex lens placed in front of the eye, causing the light rays to converge correctly on the retina.]
(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) (a) The eye ball is too short from front to back.
(b) The lens is too flat.
(iii)
[Figure: A diagram showing an eye with hypermetropia, where parallel light rays converge behind the retina. Below it, a diagram showing a biconvex (converging) lens placed in front of the hypermetropic eye, causing the light rays to converge precisely on the retina, thus correcting the vision.]

Teacher's Note:
a) This question requires identification of an eye defect from a diagram and knowledge of its causes and correction.
b) For drawing, ensure clear labels for the eye parts, the corrective lens, and the path of light rays to show proper convergence on the retina.

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

Answer:

Teacher's Note:
a) This matching exercise tests the association of biological terms with their related concepts or applications.
b) Students should carefully consider the primary function or characteristic of each item in Column A to find its most appropriate match in Column B.

(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:

Teacher's Note:
a) This question tests the ability to classify biological terms and identify the outlier based on a common category.
b) Students should identify the common theme among three terms and then correctly name the category, ensuring the odd one out truly doesn't fit.

SECTION-II (40 Marks)
(Attempt any Four questions from this Section.)

Question 2

(a) Given below is an experimental set up to demonstrate a particular process. Study the same and answer the questions that follow :
[Figure: An experimental setup showing two leaves attached to a plant. One leaf is labeled "DORSAL SURFACE" and has cobalt chloride paper attached to its upper surface. The other leaf is labeled "VENTRAL SURFACE" and has cobalt chloride paper attached to its lower surface. Both papers are held in place by glass slides and clips. The cobalt chloride paper is initially blue.]
(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 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) Transpiration is the process by which plants release water vapor into the atmosphere, primarily through stomata on their leaves, but also through lenticels on stems and the cuticle.
(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. This is because the number of stomata is generally higher on the ventral (lower) surface of a dicot leaf, leading to a greater rate of water vapor loss from that surface.
(v) 1. Cuticle becomes thick.
2. Leaves become narrow.
3. Stomata covered by hair-like structures.

Teacher's Note:
a) This question focuses on the experiment demonstrating transpiration, a key process in plant physiology.
b) Students should clearly explain the process, the experimental setup, expected observations, and the underlying reasons, along with relevant plant adaptations.

(b) Give the biological/technical terms for the following : [5]
(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.

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

Teacher's Note:
a) This section tests a broad range of biological terminology from various chapters.
b) Students must be precise with the technical terms; common names or incorrect spellings will not be accepted.

Question 3

(a) Given below is the diagram of a cell as seen under the microscope after having been placed in a solution :
[Figure: A diagram of a plant cell that has undergone plasmolysis. The cell wall is intact, but the cell membrane has pulled away from the cell wall, and the protoplast has shrunk. Labels point to: 1 - Nucleus, 2 - Chloroplast, 3 - Vacuole, 4 - Cell wall.]
(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 its original condition ? [5]

Answer:
(i) Plasmolysed
(ii) Hypertonic solution
(iii) 1. Nucleus
2. Chloroplast
3. Vacuole
4. Cell wall
(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 in a hypotonic medium or plain water for some time.

Teacher's Note:
a) This question assesses understanding of osmosis, plasmolysis, and the distinguishing features of plant cells.
b) Students should be able to identify the cell condition, the type of solution, label cell organelles, and explain the recovery process based on osmotic principles.

(b) Differentiate between the following pairs on the basis of what is mentioned in brackets: [5]
(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).

Answer:
(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. It is guarded by two guard cells.
Stroma - It is the part/region in the chloroplast where dark reaction of photosynthesis takes place. It is a fluid-filled space.
(iii) Acromegaly - Overgrowth of certain parts of body like cheek bones, hands, and feet 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 are involved.
Guttation - Hydathodes are involved.
(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.

Teacher's Note:
a) This question requires students to differentiate between pairs of biological terms based on specific criteria.
b) For differentiation questions, it is best to present answers in a comparative table format or clearly state distinct points for each term as per the given basis.

Question 4

(a) The diagram below shows the Excretory System of a Human being. Study the same and then answer the questions that follow :
[Figure: A diagram of the human excretory system. Labels are: 1 - Renal artery, 2 - Aorta, 3 - Renal vein, 4 - Posterior Vena Cava, 5 - Ureter, 6 - Urinary bladder, 7 - Sphincter muscles, 8 - Urethra.]
(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) 1 - Renal artery
2 - Aorta
3 - Renal vein
4 - 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.

Teacher's Note:
a) This question tests knowledge of the human excretory system, including its anatomy and the functions of its components.
b) Students should accurately label the parts and describe their functions, and also recall associated endocrine glands and their locations.

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

Answer:
(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 forms 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.

Teacher's Note:
a) This question requires concise and accurate definitions of fundamental biological terms.
b) Students should focus on the key characteristics and mechanisms for each term, ensuring clarity and precision in their explanations.

Question 5

(a) Study the diagram given below and then answer the questions that follow :
[Figure: A diagram of the female reproductive system, showing the uterus, fallopian tubes, and ovaries. Part A points to the ovary, and Part B points to the uterus.]
(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) A - Ovary
Two hormones are:
1. Oestrogen
2. Progesterone
(ii) (1) If fertilisation takes place, part B i.e. uterus gets prepared to receive 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.
(iv)
[Figure: A neat, labelled diagram of a human sperm. The head contains the nucleus and is capped by the acrosome. The mid-piece contains mitochondria, and the tail is a flagellum.]

Teacher's Note:
a) This question covers the female reproductive system, hormonal functions, and the process of fertilization, along with sperm structure.
b) For diagrams, ensure all specified parts are clearly labelled. For explanations, be specific about the physiological changes in the uterus.

(b) A homozygous plant having round (R) and yellow (Y) seed is crossed with a homozygous plant having wrinkled (r) and green (y) seeds. [5]
(i) Give the scientific name of the plant on which Mendel conducted his dihybridization 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.

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 two pairs of traits are combined in a hybrid, segregation of one pair of characters is independent of the other pair of characters.
(v) F₁ genotype = Rr Yy.
So possible gamete combinations are :
1. RY
2. rY
3. Ry
4. ry

Teacher's Note:
a) This question tests the understanding of Mendelian dihybrid cross principles, including genotypes, phenotypes, and associated laws.
b) Students should remember the scientific name of Mendel's plant, the F1 genotype, the F2 phenotypic ratio, and the gamete combinations for a dihybrid cross.

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 :
[Figure: Two diagrams of a variegated leaf. The first diagram, "BEFORE THE EXPERIMENT", shows a leaf with a central "Green Portion" and surrounding "White Portion". The second diagram, "AFTER THE EXPERIMENT", shows the same leaf after a starch test. Part A (corresponding to the original green portion) is shown as dark, and Part B (corresponding to the original white portion) is shown as light.]
(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: Iodine solution.
(iii) Variegated leaf/Coleus leaf (leaf having non-green and green regions).
(iv) After performing starch test:
Part A (green portion) turns blue-black with Iodine solution.
Part B (white portion) turns brown with Iodine solution.
(v) \( 6\text{CO}_2 + 12\text{H}_2\text{O} \xrightarrow[\text{Chlorophyll}]{\text{Sunlight}} \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{H}_2\text{O} + 6\text{O}_2 \)

Teacher's Note:
a) This question focuses on the experimental proof that chlorophyll is essential for photosynthesis.
b) Students should clearly state the aim, the test, the type of leaf, the expected results with reasons, and the balanced chemical equation for photosynthesis.

(b) The diagram given below show the cross section of two kinds of blood vessels :
[Figure: Two cross-sections of blood vessels. Vessel A has a narrow lumen and a thick muscular wall. Vessel B has a wide lumen and a thin muscular wall. Label 1 points to the endothelium, and Label 2 points to the lumen.]
(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
Reason for A (Artery): A has narrow lumen and thick muscular wall.
Reason for B (Vein): B has wide lumen and thin muscular wall.
(ii) 1 → Endothelium
2 → Lumen
(iii) "LUBB" - Sound is produced when the two auriculoventricular valves shut.
"DUP" sound is produced when the two semilunar valves shut.
(iv) 1. Hepatic portal Vein.
2. Coronary artery.

Teacher's Note:
a) This question tests knowledge of the structure and function of blood vessels and the sounds of the heart.
b) Students should be able to differentiate arteries and veins based on their cross-sectional features and recall the events causing heart sounds and specific blood vessels.

Question 7

(a) Answer the following: [5]
(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.

Answer:
(i)
[Figure: A well-labelled diagram of a neuron (nerve cell). It shows the cell body (cyton) with a nucleus and Nissl granules, dendrites extending from the cyton, an axon originating from the cyton, and myelin sheath interrupted by Nodes of Ranvier along the axon. The axon terminates in nerve endings.]
(ii) 1. Seat of Memory: Cerebrum.
2. Co-ordinates muscular activity : Cerebellum.
(iii) Activities of WHO:
1. Set pharmaceutical standards.
2. Suggests Quarantine measures.
3. Finances research on various diseases.
4. Suggests vaccinations against various diseases.

Teacher's Note:
a) This question covers the structure of a neuron, functions of brain parts, and the role of the WHO.
b) For the neuron diagram, ensure all specified parts are clearly labelled. For WHO activities, list distinct and significant contributions.

(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 chromosomes. [5]

Answer:
(i)
[Figure: A well-labelled diagram of an animal cell in metaphase of mitosis. It shows four duplicated chromosomes (each with two chromatids) aligned at the equatorial plate (metaphase plate). Spindle fibres extend from the two asters (centrosomes) at opposite poles, attaching to the centromeres of the chromosomes.]
(ii) 1. Desire for a male child.
2. Lack of awareness about birth control measures.
3. Decrease in death rate due to improved medical facilities.
4. Increase in birth rate due to early marriage and lack of family planning.
(iii) 1. Pituitary gland secretes hormones that regulate the functions of almost all other endocrine glands, hence it is called the master gland.
2. Gametes are produced by Meiosis, a reductional division, in which the number of chromosomes gets reduced to half. This ensures that during fertilisation, when two gametes fuse, the zygote formed has the diploid number of chromosomes characteristic of the species.

Teacher's Note:
a) This question assesses knowledge of cell division (mitosis), population dynamics, and endocrine system functions.
b) For the metaphase diagram, ensure chromosomes are clearly duplicated and aligned at the equator, with spindle fibers attached. For reasons, provide distinct biological explanations.