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IldDlml6 Ettroltrh.d; 6D lnLmi6a t9tl r= f,i' , EDuc^rloxlJExcErLENcE SECOND PRE,LIMINARY EXAMINATI ON 2023AO2 4 BIOLOGY STD: X SCIENCE TIME:2 hrs. - Paper 3 DATE:09.01.2024 MARKS:80 Answers to this paper must be written on the paper provided separately. You will not be allowed to write durtngfirsi lS minutei. This time is to be spent in readtng the question papen The time given at the head af this paper is the time allowedfa) writing the answers. Attempt all questionsfram SectionA and anyfour questionsfrom Section B. The intended marlcsfor questions or ports of questiois are given in braclcets [J. This paper consists of sir printed pages. Nothing should be writt-en on this question poper. SECTION A (Attempt all questions from this section.) Question I choose the correct answers to the questions from the given options. **(Do not copy the questioR, write the correct answers only.) (i) [1st Apair of corresponding chromosomes of the same shape, alleles and size derived one from each parent is called (a) Homologouschromosome (b) Homozygouschromosome (c) Heterozygouschromosome (d) Sex chromosome (ii) The extinct human ancestor who ate only fruits and hunted with stone weapons (a) Ramapithecus (b) Australopithecus (c) Dryopithecus (d) Homo erectus are: (iii) Angina pectoris is due to (a) defectivenutrition O) defective functioning of mitral valve (c) infection by a virus (d) chest pain due to inadequate supply of oxygen to the heart muscle Conttnued onpg 2 iivj Dupllcaticn *f cixon:cserr::res in rhe ;elt c5 c} .rou*rs dunng the rai G.i Fhase (b) Anaphase (c) S- Phase {d) G-2 Phase (v) The nitrogenous base Adenine always pairs with Thiamine Guanine Thymine (a) (b) (c) (d) Cycsine (vi) The circular opening in the centre of the iris: (a) (b) (c) (d) Pupil Lens Cornea Conjunctiva (vii)Stimulation of the nerves of the parasympathetic nervous system (a) (b) (c) (d) Acceleratesheartbeat Dilates blood vessels Decreasesperistalsis Retards heartbeat (viii) The theory of Natural Selection was proposed by (a) (b) (c) (d) (ix) When (a) (b) (c) (d) (x) Lamarck Linnaeus Waliace Darwin in solution shrinks and loses its shape, then the solution is: Isotonic a cell Potable Hypotonic Hypertonic During the Gl phase of the cell cycle the volume of cytoplasm increases as (a) RNA is synthesized (b) RNA and proteins are synthesized (c) DNA is synthesized (d) Glucose is synthesized (xi) John was walking in a park, he suddenly felt a sharp pain in his chest. He tried to ignore it, but the pain became more intense. He started sweating profusely and felt dizzy. He decided to go to the hospital. The doctor immediately started treatment for: (a) Muscular pain (b) (c) (d) Heart attack Acidity Gastritis Continued on pg 3 (xii) A single highly coiled tube where spenns are stored, gets concentrated and mature is known as Epididymis Vas efferentia Vasdeferens Seminiferous tubule (a) O) (c) (d) (xiii) Assertion (A): Fraternal twins may be both boys or both girls or one boy and one girl. Reason (R): They are formed from a single zygote. They are called Di-zygotic. A is True and R is False Ais False and R is True (a) (b) (c) (d) BothAand R are True Both A and R are False (xiv) Which of the following human ancestral stages (a) (b) (c) (d) came before the modern marfl Cro-magnon Ramapithecus Homo habilis Neanderthal man (xv) The fuII compliment of DNA of an organism is (a) Gene (b) Genome (c) Genetics (d) Heredity Question 2 (i) Name the following: t5l (a) A genetic disorder in which blood does not clot. (b) Achemical leading to the formation of ozone holes. (c) The chemical released by Basophils. (d) The part of the inner ear responsible for dynamic balance. (e) The structures which help in the fonnation of spindle fibres (ii) during cell division. Arrange and rewrite the terms in each goup in the correct order so as to be in a logical seguence, (a) Cytokinesis, G2-phase, Karyokinesis, S-phase. (b) Reabsorptiorl Filtration, Secretiorq Excretion. (c) Eardrum, Sound wave, Vibration,Impulse. (d) Loss of water, Transpiration, Stomata closed, Stomata flaccid. (e) Sensory neuron, Receptor, Spinal cord, Motor neuron. (iii) Fill in the blanks with suitable words: tsl tsI Blood platelets are produced in (a) ............They get destroyed in the (b) They initiate (c) at the site of bleeding. They produce (d) .......,.. which in the presence of calcium converts (e)........... ofplasma into thrombin. Continued onpg 4 {it'i (v) Choose the *dd one *r.rf frorn the follox,i*g terrns and name the categ*r_v which others belong. (a) Glucocorticoids, Mineralocorticoids, Glucagon, Sexcorticoids. (b) Thrombin, Fibrinogen, ThrombosiS, Fibrin. (c) Loudspeaker, Amplifier, Music, Dust. (d) Needles, Dressings, Syringes, Pesticides. (e) Oil spills, Kitchen waste, Detergent, Excreta. t* Match the iterns given in Column I with the most appropriate ones in Column and rewrite the correct matching pairs. Column I Column II A. Diabetes insipidus iI fE1 tJ_l Anterior pituitary 2. Posterior pituitary 3. Adrenal cortex 4. Thyroid 1. B. Addison's disease C. Myxoedema D. Acromegaly E. Diabetes mellitus 5. Pancreas 6. Parathyroid 7. Adrena] medulla SECTION B (Axempt anyfour questionsfrom this section.) Question 3 (i) Explain Mendel's Law of IndependentAssortment. tll (ii) One rotten orange can spoil the whole basket (iii) State the dominant and recessive char:acters in a pea plant with respect to pod and fullof oranges. Give reason. flower- (iv) ttrat (v) is Adrenal L2l tzl Virilism ? What causes this condition ? LTl Given below is the diagram of a set up to study a very important physiological process. Study the diagram and answer the questions that follows. (a) Name the process being studied. (b) What change would you expect to observe in the thistle funnel containing sugar solution after about 10 minutes? (c) Name the part of a plant cell which is represented by and acts as the parchment paper and sugar solution. [3] SJGlfI SO.LIT}C\ .}AqCHVENI PAP B Question 4 (i) Define Speciation. (ii) considering example of giraffe, explain use and disuse of organs. (iii) Write difference between Blood Plasma and Serum? (iv) How do sewage fleatment plants reduce pollution? (v) Draw and label the structure of a chloroplast. lll 121 I2l B1 t3l Continued on pg 5 Question 5 (i) Give scientific reason for the statement *Law of segregation is also called Law of Purity of gametes". tll of animals black fur (B) is dominant over brown fur (b). predict u g*ootyp" and phenotype of the off-springs when both parents are Bb or have heterozygous black fur. t21 State the importance of meiosis. 12) (ii) h (iii) a certain species (iv) What is ozone hole? How are they produced? How it affects the life on the earth? t21 Given below is an outline of the human body showing the important glands. (a) Name the glands marked 1 to 5. t3l (v) 2 1 (b) Name the hormone secreted bY 7. Give one important function of this hormone' (c) Name the endocrine cells present in part 6' 3 4 5 Question 6 (i) 5 7 What does "like begets like" mean? (ii) State the functions of pericardial fluid' (iii) State the tunctions of : a) ADH b) ACTH t2l chordae tendineae ? l2l (iv) What is the function of (v) 121 t3l meiosis: The given figure represents a certain phenomenon that occurs during SH*jffiffi" hH-HH Question 7 (i) tu What is Theory of Natural Selection ? (ii) Distinguish between Homo erectus and Homo habilis. (iii) Name the blood vessel which 121 has got the ma:rimum amount of glucose and give 12) reasons for Your answer- (iv) The need to limit the size of the family is more vital today than ever before. L2) Give two reasons. (v) The diagram below represents a certain category of blood vessels showing the role of special structure intheir walls: t3l ! a kind of blood vessels shown' r^ @) Name the \l (ol Name the structure shown inside the blood vessels' structures' i-(o) Describe the role of these I I I ll Continued on pg 6 Question (i) \[&at I I I is vitreous humour? [1t (ii) (a) At the start of a race, athletes react to a starter gun which involves a number of events. [2] Put the following events in correct order beginning with (c). (A) Co-ordination by brain @) Detection by receptors (C) Stimulus (D) Response (E) Effector change (b) write one difference between voluntary and reflex action. (iii) Give reasons for the following: (a) In pineapple, auxin is used. (b) Abscisic acid is also called stress hormone. (iv) (a) State the features of Neanderthals with (v) t2) respect to cranial capacity and chin. (b) What function did the wisd.om teeth perform? t21 The diagram glven berow shows the mare urinogenital system of a human being. Study the diagram and answer the questions that follow: t3l 2 (a) Label the parts numbered 1 to g. (b) Name the corresponding structure of part (4) 3 4 in female reproductive system. (c) What is the role of the parr identified in (b)? **** *** 6 7
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