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DELHI PUBLIC SCHOOL NEWTOWN SESSION 2018-2019 PREBOARD EXAMINATION CLASS: X SUBJECT: BIOLOGY [SET: A] FULL MARKS: 80 TIME: 2 HOURS Answers to this paper must be written on the paper provided separately. You will not be allowed to write during the first 15 minutes. This time is to be spent in reading the question paper. The time given at the head of this paper is the time allowed for writing the answers. Attempt all questions from Section I and any four questions from Section II. The intended marks for questions or parts of questions are given in brackets [ ]. This question paper consists of 7 printed pages. SECTION I (40 Marks) Attempt all questions from this Section QUESTION 1 (a) Name the following: [5] i. Specialised cells in the ovary and testis that undergo meiosis. ii. The process by which plants lose water in the liquid state. iii. The substance released by injured tissue cells and platelets at the site of a wound. iv. The fluid entering the renal tubule. v. Outermost tough protective membrane of the meninges. (b) Correct the following statements by changing the underlined word only: i. Methanol is released at the synapse. ii. Deficiency of insulin causes diabetes insipidus. iii. Menopause is the onset of menstruation in a young female. iv. Australopithecus were the first ancestors to hunt animals and use fire. v. Demography is the number of individuals living per km2 at any given time. [5] (c) Give the technical terms for the following: i. Ligation of the oviducts in females. ii. A wave of electrical disturbance that sweeps over the nerve cell. iii. A rise in blood pressure above 140/90. iv. Addition of phosphate to form ATP in the presence of light. v. The tendency of water molecules to remain joined to each other. [5] (d) Given below are six sets, with four terms each. In each set, one term is odd and cannot be grouped under the 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 one has been done for you as an example: [5] Example: Nose, Tongue, Arm, Eye A/1 Answer: Odd term Arm Category Sense organs i. Detergents, X-rays, sewage, oil spills. ii. Lumen, muscular tissue, connective tissue, pericardium. iii. Dendrites, Medullary sheath, Axon, Spinal cord. iv. Bile, Urea, Uric acid, Ammonia. v. Phosphate, RNA, Sugar, Nitrogenous base. (e) Given below is a diagram of an experimental setup. Answer the questions after observing the diagram carefully: i. ii. iii. iv. v. [5] Name the apparatus shown above. How is the air bubble introduced in the capillary tube? What does this instrument measure? Mention one limitation of using this instrument. If this setup is placed in front of a table fan, what change would you observe? (f) Choose the correct option from the alternatives given below: [5] i. People with hypermetropia often need reading glasses because (A) The eye lens cannot bring distant objects into focus on retina (B) The eye lens does not bulge enough to bend the light rays reflected from the print on the page (C) Corrective lenses will make the retina more sensitive to light (D) The curvatures of the lens and retina do not match each other, causing letters on the page to appear distorted ii. In heterozygous condition an allele masks the effect of the other. The allele that masks the effect of the other is known as _______ allele and the masked allele is known as the _______ allele. (A) dominant, pseudodominant (B) pseudodominant, recessive (C) dominant, recessive (D) dominant, incomplete iii. Which of the following pairs is/are incorrectly matched? (a) Implantation Uterus (b) Fertilization Seminiferous tubule (c) Spermatogenesis Fallopian tube (d) Oogenesis Ovarian follicle (A) (a) and (c) A/2 (B) (b) and (c) (C) (a) and (d) (D) (b) only iv. A pure tall plant and a pure dwarf plant are crossed to produce F1 generation. The plant of the F1 generation is self-pollinated to produce the F2 generation. The phenotypic ratio of the F2 progeny would be (A) 1 tall : 1 dwarf (B) 3 tall : 1 dwarf (C) 1 tall : 2 medium : 1 dwarf (D) all tall v. What happens when the left ventricle of human heart contracts? (A) The oxygenated blood is forced into the main artery (B) The deoxygenated blood is forced into the pulmonary artery (C) The deoxygenated blood is pumped into the lungs through pulmonary artery (D) The deoxygenated blood goes into different body organs through pulmonary vein (g) Complete the following table: [5] Plant hormone Site of synthesis One important function Auxin i. Promote cell elongation Gibberellins Meristems of apical buds and roots ii. Cytokinins iii. Stimulate cell division Ethylene Senescent leaves and flowers iv. Abscisic acid v. Induces dormancy of seeds and buds (h) Explain the following terms: i. Hydrotropism ii. Squint iii. Root pressure iv. Implantation v. Pulse [5] A/3 SECTION II (40 Marks) Attempt any four questions from this section QUESTION 2 A. The diagram below shows salt solutions of different concentrations in relation to plant cells. Observe the diagram and answer the questions that follow: [1+1+ +1+1 ] X A i. ii. iii. iv. v. vi. B C Name the phenomena being exhibited in beaker A and beaker C. What is the state of the cell in beaker A and beaker C? What type of solution will you find in the area marked X in beaker C? When a person dehydrates, he is given intravenous isotonic saline and not plain water. Justify. To recover the cell in beaker C to its normal state, which beaker should it be placed in? Justify your answer. Name the state of this cell after being recovered. What would happen if the membrane of bag X was freely permeable? B. Give reasons for the following: [5] i. Before a bouquet of flowers is covered with a cellophane paper, the florist usually sprays the flowers with a solution of abscisic acid. ii. An Rh-negative woman is usually discouraged from marrying an Rh-positive man. iii. A person urinates more frequently in winter as compared to that in summer. iv. An alcoholic person walks clumsily. v. Simple goitre is common in people living in hilly regions. QUESTION 3 A. The figure below shows an experimental setup in photosynthesis. Observe it carefully and answer the questions that follow: [1+1+2+1] i. Write the aim of the experiment shown above. A/4 ii. iii. iv. Why is the plant destarched prior to the experiment? What will you observe after testing the leaf inside the flask for the presence of starch? Justify your observation. Write the balanced chemical equation for photosynthesis. B. Given below are certain functional activities of specific structures in the body of living organisms. Name the structure responsible for the same: [5] i. Generates impulses which start the heartbeat. ii. Reabsorption of most of the water, much of glucose, Na+ & Cl- ions. iii. Carries impulses from one hemisphere of cerebellum to the other hemisphere. iv. Static balance of the body. v. Production of testosterone. QUESTION 4 A. The diagram given below shows the internal structure of human heart. Observe the diagram carefully and answer the questions that follow: [3+1+1] A B F E C D i. ii. iii. Label the parts A F. Name the blood vessel which supplies oxygenated blood to the cardiac muscles. What is myocardial infarction? Why are the valves supported by chordae tendinae? B. Given below is an experimental setup showing a phenomenon in plants. Observe the diagram carefully and answer the questions that follow: [2+1+2] Potted plant before it falls over i. ii. Potted plant after it falls over Name the tropic movements shown by the roots and shoot. What is the stimulus that made the roots grow downwards? A/5 iii. What is the benefit of this specific tropic movement for the roots and shoot? QUESTION 5 A. The diagram below represents a sectional view of the human female reproductive system. Study the diagram and answer the questions that follow: [2+2+1] i. ii. iii. Label the parts numbered 1, 3, 5 and 7. Write the two features of the part labeled 5 which help the ovum to be picked up and travel inside it. Write one important function of amniotic fluid. B. Match the items given in Column A with the most appropriate ones in Column B and rewrite the correct matching pairs: [5] Column A Column B i. Spinal nerves a. 12 pairs ii. Inner portion of b. Controls cerebrum heartbeat iii. Medulla oblongata c. Iodopsin iv. Playing a musical d. White matter instrument e. Rhodopsin v. Cone cells f. Grey matter g. 31 pairs h. Conditioned reflex QUESTION 6 A. Study the figure given below and answer the questions that follow: i. Name the ancestral human as shown in the figure. A/6 [ +2+1+ +1] ii. iii. iv. v. Write four important characteristics of the ancestral human named by you in (i) above. Mention the height and cranial capacity of this ancestral human. Name the scientist who proposed the Theory of Natural Selection. Explain the Principle of Use and Disuse as proposed by Lamarck with a proper example. B. Differentiate between the following pairs of terms based on the criteria given in brackets: i. Phototropism and Thigmotropism (stimulus) ii. Metaphase and Anaphase (position of chromatids) iii. Active transport and Passive transport (direction of molecular movement) iv. Gestation and Parturition (definition) v. Haematuria and Glycosuria (unusual component in urine) [5] QUESTION 7 A. Study the picture given below and answer the questions that follow: i. ii. iii. iv. [ +1 +2+1] Identify the type of pollution shown in the picture above. Name three sources of the pollution named by you in (i) above. Write two harmful effects of the pollution named by you in (i) above. Mention one way to minimise the type of pollution named by you in (i) above. B. Study the diagram given below and answer the questions that follow: i. ii. iii. Identify the procedure shown in the diagram. How is this procedure useful in population control? Name and briefly explain the three barrier methods of contraception. A/7 [1+1+3]
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