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(The first 15 minutes of the examination are for reading the paper only.) ------------------------------------------------------------------------------------------------------------ Answer all questions in Part I and five questions from Part II, choosing three questions from Section A and
two questions from Section B.
All workings, including rough work, should be done on the separate answer sheet as an adjacent to; the rest The intended marks for the questions are given in brackets [ ] Answer all questions.
QUESTION 1.
Each question is followed by four possible choices of answers. Choose the correct answer and write it (i)Interferon’s inhibits the infection of (ii) Tropical plant like Sorghum is efficient carbon dioxide fixers due to operation of (iii) Heart rot disease of sugar beet is mainly due to deficiency of (iv) Conjoint, Collateral, Open and Endarch vascular bundles are found in (a) natural selection (b) survival of the fittest (c) evolution through mutation (d) struggle for existance (vi) The change of gene frequency from one generation to next is known as QUESTION 2
Fill in the blanks with suitable words 1. Bulliform cells are formed in the epidermis of . leaf 2. If wall pressure of a cell decreases, DPD of that cell will.
3. The conversion of Ammonia to nitrite and then to nitrate is called.
4. A …………fruit is derived from one carpel or the fused carpels of a single flower, whereas an aggregate fruit is derived from several carpels of a single flower.
5. A blue copper protein involved in light reaction of photosynthesis is.
6. Reabsorption of water from urine is increased by the hormone………………while reabsorption of Na ions from urine is enhanced by …………………… 7. . is a plant hormone responsible for reversal of Dwarfism 4. Epithelial tissue lining a blood vessel is.
--------------------- is the study of mode of transmission of various communicable diseases.
10. In a C3 plant, CO2 fixation takes place in the …………cells, whereas in a C4 it takes place in QUESTION 3
Supply the appropriate term /answer for each of the following 1. Human baby born with a hole in ventricular septum 2. Manure consisting of rotten vegetables and animal refuse 3. Chemical that can be used as a fuel for automobiles 4. Number of organisms required to cause disease 5. Process of formation of blood corpuscles.
6. A species occupying the same range as another species but maintaining identity by not interbreeding 7. The most recent direct pre-historic ancestor of present man 8. A structural change in chromosome which appears phenotypically 9. Transfer of a part of chromosome or a set of genes to non homologous chromosome 10. Preservation of germplasm at ultra low temperature QUESTION 4
(a) Match each item under Column A with that which is most appropriate in Column B. You must rewrite f. Hyper secretion of Growth hormone.
QUESTION 5
Give one significant difference between each of the following 1) Auxetic growth and Accretionary growth QUESTION 6
1. Prior to sowing rice, a legume was cultivated and ploughed back in the field.
2. It is unusual to get the same infectious disease more than once.
3. Hybrid vigour is best maintained in vegetatively propagating crops 4. Shoot tips are usually selected as explants in plant tissue culture.
5. Heart wood ceases the function of conducting tissue and gives support to the stem QUESTION 7
1. EDTA. 2. EEG 3. CT- scan 4.IPM 5.VAM 6.ABA 7. NAA 8. IBA Give the best contribution of the following scientist SECTION A
Answer any three questions
QUESTION 8
2. Explain the general characteristics of the three types of permanent tissue with the help of the L.S 3. Define turgor pressure. Explain four significance of turgidity in plants.
4. Draw the L.S of an ovary to show the process of fertilization in angiosperms QUESTION 9
1. Describe the flow of electrons in non- cyclic photophosphorylation and compare it with that of cyclic
2. What is meant by ascent of sap? Which tissue act as the path of ascent of sap? How does Dixon’s 3. Describe the process of urine formation in kidneys.
QUESTION 1
1) Kranz anatomy helps in performing the act of maximum carbon dioxide utilization. Justify this 2) If a tobacco plant is kept in short day conditions in summer for more than 12 hours of daylight, how would this effect the flowering of the plant? 3) Describe the mechanism of the stomatal opening with help of the diagrams and explain the role of QUESTION 11
1. How do functions of Cytokinin differ from Gibberellins?
2. Describe an experiment that would demonstrate that the growth stimulating hormone is produced at 3. Draw the V.S of Eye and label the parts
4. Mention how RBC’s maintains electrostatic neutrality.
QUESTION 12
1. Enlist the general functions of the mineral elements in the life of a plant.
2. Explain the role played by phytochrome in seed germination 3. Describe the flow of blood through heart during different phases of the cardiac cycle 4. Name and describe the sequence of steps in the formation of urea.
SECTION B
Answer any two questions
QUESTION 13
1. Describe the Humoral and Cell mediated immune reaction towards the entry of antigens [4] 2. Genetically modified food is common these days but they should be released in the market after conducting appropriate tests. Comment.
3. Mention some important reasons for drug addiction.
4. Define Metastasis. Suggest three early diagnostic symptoms or danger signals of Cancer. [3] 5. Give a note on deficiency disease and degenerative disease.
QUESTION 14
1. Why is genetic variability essential for a species to survive? 2.”Mutation is raw material for evolution.” Justify the statement.
3. Emblicaofficinalis and Aloe vera are found abundantly in Bhutan. Give two important medicinal uses 5. What is endoscopy?Differentiate between laproscope and gastroscope 6. What is sickle cell anemia? Why does nature favour existence of sickle cell Anemia? QUESTION 15
i) Rabies is also known as hydrophobia.
ii) Babies separated from the leper (suffering from leprosy) parents in early life grow into a healthy iii) Skin grafted from other person of same species is rejected.
2) Mammals are evolved from reptiles”, how embryological evidences of evolution support this statement 4) What do you understand by innate immunity and acquired immunity? 5) What is genetic counseling? What role is played by amniocentesis in genetic counseling? QUESTION 16
3. Polyploidy is genetic mechanism that leads to origin of new species. Support the above statements with example of origin of Hexaploid wheat.
4. What are the advantages of Micropropagation? 5. Give an account of Lederberg’s Replica Plating experiment to show genetic basis of adaptation. [4]

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