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STD: X TIME: 2 hrs. SECOND PRELIMINARY EXAMINATION 2020-2021 BIOLOGY DATE: 05.02.2021 MARKS: 80 Answers to this paper must be written on the paper provided separately. You will not be allowed to write during the first 15minutes. 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. ____________ This paper comprises of two sections - Section I and Section II. Attempt all the questions from Section I. Attempt any four questions from Section II. The intended marks for questions or parts of questions are given in brackets []. This paper consists of six printed pages. Nothing should be written on this question paper. SECTION I (40 Marks) Attempt all questions from this section. Question 1 a) State whether the following statements are true or false. If false, rewrite the correct statement. (i) (ii) (iii) (iv) (v) [5] The pancreas is the largest endocrine gland. Hypothalamus is the part of midbrain. Destarching of plant is done by keeping plant in the dark for 24-36 hours. Chordae tendinae is also called as yellow spot. Water and minerals coming out of root hair is called as cell sap. b) Given below is an example of a certain structure and its special functional activity. On a similar pattern fill in the blanks with suitable functions: Example: Chloroplast and photosynthesis (i) Xylem and . (ii) Ciliary body and . (iii) Semicircular canal and . (iv) Thyroid gland and . (v) Eustachian tube and . [5] c) Complete the following paragraph by filling in the blanks (i) to (v) with appropriate words:[5] (i) ___________ is secreted by the ( ii) _______________ lobe of the pituitary gland. If this hormone secretion is reduced, there is an increased production of urine. This disorder is called (iii) . Sometimes excess glucose is passed with urine due to hypo secretion of another hormone called (iv)___________ leading to the cause of a disease called (v) . Cont d on page 2 . 1 d) The statements given below are incorrect. Rewrite the correct statement by changing the underlined words in the statements. (i) (ii) (iii) (iv) (v) [5] Duplicated chromosomes remain attached at a point termed centrosome. Deafness is causal due to the rupturing of the Pinna. Gyri and Sulci are the folds of Cerebellum. Free movement of solutes in and out of the cell takes place across the cell membrane. The solvent used to dissolve the chlorophyll pigments while testing a leaf for starch is Soda lime. e) What do the following abbreviations stand for? (i) SNS (ii) ADP (iii) HB (iv) TSH (v) CSF [5] f) Name the following. (i) The pigment that transforms light energy to chemical energy. (ii) The clear liquid that protects the eye lens from shock and keeps it moist. (iii) The form in which glucose is stored in liver. (iv) The primary excretory organs of humans. (v) The compound formed when hemoglobin combines with carbon dioxide in blood. [5] g) Choose the correct alternative from the choices given below each statement so as to complete its meaning. (i) The number of daughter cells formed at the end of meiosis from a cell is (A) 2 haploid cells (B) 2 diploid cells (C) 4 haploid cells (D) 4 diploid cells [5] (ii) Plasmolysis identifies the process of (A)Imbibition (B) Active transport (C)Diffusion (D)Osmosis (iii) Which of the following is not a part of the nephron? (A)Malpighian capsule (B)Henle s loop (C)Neuro lemma (D)Proximal convoluted tubule (iv) Marine fish when placed in tap water bursts because of: (A)Endosmosis (B)Exosmosis (C)Diffusion (D)Plasmolysis (v) Chromosomes get aligned at the center of the cell during: (A) Metaphase (B)Anaphase (C)Prophase (D)Telophase Cont d on page 3 . 2 h) Given below is a diagram of human ear, study the same and then answer the questions that follow: [5] (i) Identify the structure that A) Converts sound wave to mechanical wave. B) Converts vibration into nerve impulse. C) Responds to change in position. (iii) Name part I. (iv) What is the function of part labelled H.? SECTION II (40 Marks) Attempt any four questions from this section. Question 2 a) Given below is the schematic representation of circulatory system in human. Study the same and answer the questions that follow. [5] (i) Label part 1 and 3 indicated in given diagram. (ii) Give one difference between part 1 and 2 based on: (A) Their structure. (B) The nature of blood flowing through them. (iii) What is the specific name of the type of blood circulation that takes place between the heart and the lungs? (iv) Name the valve found at the beginning of part labelled 3. b) State the functions of the following. (i) Lenticels (ii) Stroma (iii) Spleen (iv) Corpus callosum (v) Lacrimal glands [5] Cont d on page 4 . 3 Question 3 a) Given below is a diagram depicting a defect of the human eye, study the same and then answer the questions that follow: (i) (ii) (iii) (iv) Name the defect shown in the diagram. What are the two possible cause of this defect? Name the type of lens used to correct this defect. With the help of a diagram show how the defect shown above is rectified using a suitable lens b) Differentiate between the following pairs on the basis of what is mentioned within brackets: (i) (ii) (iii) (iv) (v) [5] Human skin cell and Human ovum (number of chromosomes). Rod cells and cone cells(pigment) LUBB and DUP (names of the valves whose closure produce the sound) Adrenal medulla and adrenal cortex (hormones produced) Eosinophil and neurotrophil (shape of nucleus) Question 4 a) The diagram of an apparatus given below demonstrates a particular process in plants. Study the same and answer the questions that follow (i) (ii) (iii) (iv) (v) [5] [5] Name the apparatus. Which phenomenon is demonstrated by this apparatus? State two limitations of using this apparatus. What is the importance of the air bubble in the experiment? Name the structures in a plant through which the above process takes place. Cont d on page 5 . 4 b) Give scientific reasons for the following statements: (i) (ii) (iii) (iv) (v) [5] The number of leucocytes increase during infection. Injury to medulla oblongata leads to death. Medicines dropped in the eye flow down into the nose. Transpiration is the price which the plants pays for photosynthesis. Blood flows in arteries in spurts and is under pressure. Question 5 a) The diagram given below is a structure of human brain. Study the same and answer the questions that follow: [5] (i) Name the lobes present on the part labeled 9. (ii) Label parts 5 and write its function. (iii) Name the two protective covering present around the given diagram? (iv) Write the arrangement of neuron in the structure labelled 8. b) Give appropriate biological or technical terms for the following: (i) Process of maintaining water balance in the blood. (ii) Hormones which regulate the secretion of other endocrine glands. (iii) Movement of molecules of a substance from their higher concentration to lower concentration when they are in direct contact. (iv) The process by which leucocytes engulf and destroy bacteria. (v) The complex consisting of a DNA strand and a core of histones. (vi) A chemical that changes color in the presence of moisture. (vii) Squeezing out of white blood cells from the capillaries into the surrounding tissues. (viii) Substances that increases the urine formation. (ix) The relaxation phase of the heart. (x) Exudation of plant sap from injured part of the plant. [5] Cont d on page 6 . 5 Question 6 a) A potted plant with variegated leaves was taken in order to prove a factor necessary for photosynthesis. The potted plant was kept in the dark for24 hours and then placed in bright sunlight for a few hours. Observe the diagram and answer the questions. [5] (i) What aspect of photosynthesis is being tested in the above diagram? (ii) How the process will be affected if the light intensity is high? (iii) What will be the result of the starch test performed on leaf A shown in the diagram? Given an example of a plant with variegated leaves. (iv) Draw a neat labelled diagram of a chloroplast. b) Answer the following questions (i) State the significance of mitosis. (ii) Draw a neat labelled diagram of human eye. (iii) Explain the importance of calcium in blood clotting. Question 7 a) Given below is a diagram representing a stage during mitotic cell division. Study it carefully and answer the questions that follow: [5] [2] [2] [1] [5] (i) Is it a plant cell or an animal cell? Give a reason to support your answer. (ii) Identify the stage shown. (iii) Name the stage that follows the one shown here. How is that stage identified? (iv) Write two point of difference between mitosis and meiosis b) Answer the following (i) State the location of the following. A) Synapse B) Ciliary body (ii) Draw a neat labelled diagram of longitudinal section of human kidney. (iii) Define micturition. ********************* 6 [5] [2] [2] [1]
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