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PRE- BOARD- II EXAMINATION 2020-2021. BIOLOGY SCIENCE PAPER -3. CLASS X NOTE: 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 [ ] . SECTION I(40 marks) Attempt all questions from this section. Ques 1: (A) Name the following: i) ii) iii) iv) v) [5] The nutritive layer of eye which prevents reflection of light. The inorganic ion present in chlorophyll. The part of chloroplast where light reaction takes place. A process by which plant exudes water from the margins of the leaf. The smallest common blood vessel formed by union of capillaries. (B) Give the main function of: [5] i) Vitreous humour. ii) Lenticels. iii) pericardial fluid. iv) Cuticle. v)Loop of henle. (C ) State whether the following statements are True or False. Correct the false statements and rewrite. [5] i) ii) iii) iv) v) Papillary muscles in the heart holds the apices of valves in position. The cells which have lost their water content are said to be deplasmolysed. Cones enable us to see three primary colours. Glucagon hormone is produced by beta cells. Corpus callosum is the sheet of fibres present between two cerebral hemispheres (D) Given below are the set of five terms without changing the first term rearrange the remaining four. [5] i)Grass, Insects, snake, frog, peacock. [ food chain] ii) Interphase, Metaphase, Telophase, Prophase, Anaphase.[ Karyokinesis] iii) Root hair cells, Xylem, cortex, endodermis, pericycle. [conduction of water] iv) Photon, Hydrogen and hydroxyl ion, grana, water, oxygen.[photolysis]. v)Platelets disintegrates, fibrogen, fibrin, thrombus, thrombokinase.[clotting of blood]. (E) Given below is the figure of a body system study the diagram and answer the following questions: [5] i) ii) iii) iv) v) Name all the organ systems which are shown in the diagrams. Name the parts labelled 1 to 5. Name the structural and functional unit of part labelled 1. Name two main organic constituents of the fluid which flows down the parts labelled 3. Name the two major steps involved in formation of the fluid which passes down the part labelled 3. (F) Give the exact location of: [5] i) Ciliary body. ii) Pituitary gland. iii) Hypothalamus. iv) Bowman s capsule. v)Coronary artery. (G) Differentiate between the following on the basis of what is mentioned in the bracket: i) Rods and cones (distribution). ii) Sympathetic and parasympathetic (Location). iii) Renal cortex and renal medulla (parts of nephron present). iv) LUBB and DUBB (name of the valves closed). v)Hypertonic and Hypotonic solution (definition). [5] (H) Match the items in column 1 with the most appropriate in column 2 and rewrite the correct matching pairs. [5] 1) Pacemaker a. Associated with static body balance 2) Stroma b. chordae tendinae 3) Sensory neuron. C. Site of light reaction 4) Prolactin. D. Stimulates milk ejection. 5) Sacculus e. SA node. f. Site of dark reaction. g. Stimulates production of milk by mammary gland. h. Transmits impulses from spinal cord to muscles. i. Secreted by posterior lobe of pituitary gland. j. Transmits impulses from receptor to spinal cord. SECTION II Attempt any four questions Ques 1 (A) Study the diagram and answer the questions given below : I) II) III) IV) V) [5] Name the cells of pancreas that produce insulin. Why is pancreas referred to as an exo-endocrine gland? Why is insulin not given orally but injected into the body ? What is the technical term for cells of pancreas that produce endocrine hormones ? Write two symptoms of diabetes mellitus? (B) Give biological reasons for the following: a) Some women have facial hair like beard and moustache. Why? b) An alcoholic person walks clumsily. Why? c) Blood flowing away from stomach and intestine is put into circulation via liver and not directly. Give two main reasons. d) In summer the urine is slightly thicker than in winter. Why? e) In xerophytes leaves are modified to spines. [5] Ques 2: (A) Draw a diagram of human eye as seen in a vertical section and label the parts which suit the following functions / descriptions: [5] i) ii) iii) iv) v) The structure which alters the focal length of the lens The region of distinct vision. The part which transmits the impulse to the brain. The outermost transparent part of SCLERA in front of eye lens. The fluid present in the anterior part of the eye in front of eye lens. (B) A leaf cell of a water plant was placed in a liquid other than pond water after some time it assumed a shape as shown below: [5] i) Give the term for the state of the cell it has acquired. ii) Comment on the nature of liquid surrounding the cell. iii) Name the structure which acts as selectively permeable membrane. iv) Redraw the diagram of the cell if it is soon placed in ordinary water for some time. Ques 3: (A) Given below is a stage during mitosis cell division study the same and answer the questions that follows: a) Identify the above stage give a reason to support your answer. b) Label the parts 1,2,3. [5] c) Write the function of part 1. d) Draw a well - labelled diagram of the stage that comes just after this. Name the stage also. e) Define the term homologous chromosomes. (B) The diagram given below is an experimental set up to study the factor necessary for photosynthesis study the same and answer the questions given below: [5] a) Which factor of photosynthesis was being studied? b) What type of leaf was used in the experiment. Give an example. c) Before the experiment the potted plant was kept in dark for 24 to 72 hours. Why was it kept in dark? d) Describe step by step how the candidate proceeded to test the leaf for the presence of starch. Write the observation in A and B part of leaf. Ques 4: (A) The diagram given below represents the spinal cord of a mammal seen in a transverse section and a process associated with it. Study the same and answer the question that follows: [5] I) II) III) IV) V) Name the parts 1,2,3 and 4 indicated by guidelines. What do the arrows in the diagram indicate. Give the technical term for the same. Name and explain the process mentioned in part (ii). How does the arrangement of cells in spinal cord differ from that in the brain? Give two examples of conditioned reflex. (B) Explain the following terms: [5] a) Phosphorylation. b) Double circulation. c) ultra-filtration. d) Cretinism e) Guttation. Ques 5: (A) The diagram below represents the simplified pathway of the circulation of blood. Study the same and answer the questions: [5] i) ii) iii) iv) v) Name the parts labelled 1, 2, 4 and 6. Give the name of the vessel which contains maximum amount of urea a few hours after a protein rich meal. Name the only vein which contains oxygenated blood. Draw the diagram of RBC, Neutrophils, Eosinophil and Basophil. Define diapedesis. (B) Answer the following question: 1) Write the function of guard cells. 2) Mention three adaptation found in plants to reduce transpiration. 3) Explain the mechanism of opening and closing of stomata[ potassium ion concentration theory]. [5]
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