Fonte: gare di altri paesi/India/biologia/inbo2013-Q.pdf · Apri PDF · apri PDF p.1
Cluster: Meccanica
Soluzioni (stessa cartella): · · · · · · · · · · ·
Problema 1
each question
INSTRUCTIONS SHEET – INBO 2013
The question paper is divided into Section A and Section B.
All answers should be written in the answer sheet booklet only which will be collected at the end of the examination.
The question paper need not be submitted to the examiner.
Section A
Section A consists of 34 questions carrying 1 point each.
All 34 questions are of multiple choice type, with only one correct answer for each question.
Mark the correct answer with ‘✔’ on the answer sheet provided. The correct way of marking is shown below. Use a pen to mark your answer.
Q. No. a b c d
✔
Each wrong answer will have negative marking as indicated in the scoring key.
Section B
Section B consists of 22 questions with a total of 66 points.
The points for the questions in Part B vary depending on the number of answers and the complexity of the question. These points have been indicated along with the question. Contradictory answers will not be considered for marking.
SCORING KEY
NO. OF CORRECT ANSWERS: X
NO. OF INCORRECT ANSWERS: Y
SCORE INBO (THEORY): SECTION A: 3X – Y
SECTION B: 3X
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INDIAN NATIONAL BIOLOGY OLYMPIAD – 2013 SECTION A
CELL BIOLOGY (5 points)
- (1 point) The standard free energy change and standard activation energy for four biochemical reactions are listed in the table below: Reaction Standard free energy change (kcal/mol) Standard activation energy (kcal/mol) P
- 40 18 Q -71 18 R
- 40 11 S -71 11
A few interpretations are given below. Among these, the most appropriate interpretation is: a. P, Q, R and S represent the same reaction carried out in the presence of enzyme, high temperature, absence of enzyme and low temperature, respectively. b. Q and S represent the same reaction carried out at high and low temperatures, respectively. c. R and S represent the same reaction carried out in the presence and absence of catalyst, respectively. d. P and R represent the same reaction carried out in the absence and presence of enzyme, respectively.
- (1 point) For a somatic cell with 2n = 4, which of the following is true? (Note: G1- growth phase 1, G2 - growth phase 2, M - metaphase, P - prophase and T - telophase) a. (Number of chromatids)G2 = 4; (Number of chromosomes)G1 = 4 b. (Number of chromatids)G1 = 8; (Number of sister chromatids)T = 8 c. (Number of chromatids)P = 8; (Number of chromosomes)G2 = 4 d. (Number of chromatids)G2 = 4; (Number of chromosomes)M = 8
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- (1 point) Differential centrifugation separates cellular components based on the differences in their size and / or density. A tissue sample was homogenized and three parts (aliquots) of this homogenate were subjected to differential centrifugation using three different methods as indicated below:
Method I: Aliquot 1 was centrifuged at 200,000g for 2 h.
Method II: Aliquot 2 was centrifuged at different speeds and for variable durations as indicated below: Step 1: 1,000g for 10 min Step 2: 20,000g for 20 min Step 3: 80,000g for 1 h Step 4: 200,000g for 2 h
Method III: Aliquot 3 was processed in the same manner as aliquot 2, except that the sediment and supernatant were separated after each step.
Cellular components can be obtained as separate fractions from which of these methods? a. Only method I b. Only method II c. Only method III d. Both methods II and III
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- (1 point) The following figure represents the concentrations of solutes P, Q, R and S in the two compartments A and B which are separated by a semipermeable membrane. The molecule that is actively transported across the membrane is:
a. P b. Q c. R d. S
Compartment B Concentration 2X 1X Semi-permeable membrane time Concentration 2X 1X Semi-permeable membrane Compartment A Compartment B Compartment A P: Q: R: S:
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- (1 point) Action potentials involve changes in the membrane potential of an axon, as shown in the schematic below.
During the refractory period, sodium channels are inactivated and cannot be opened by depolarization. Such a ‘temporary’ inactivation mechanism has evolved and ensures: a. the sodium channel has ample time to revert to its ‘resting state’ conformation. b. the action potential travels unidirectionally. c. Na+,K+-ATPase has sufficient time to pump Na+ out. d. the membrane potential stays below the resting potential of Na+.
PLANT SCIENCES (10 points)
- (1 point) In an experiment, isolated chloroplast thylakoids were incubated at pH 4.0 with ADP and inorganic phosphate (Pi) added to the medium and then transferred to a medium having pH 8.0. After sometime, an agent ‘X’ that makes membrane permeable to protons is added to it. What would happen? a. On transferring to medium with pH 8.0, ATP formation would occur only on addition of X.
5 b. There will be ATP formation in the medium at pH 8.0 and X will have no effect. c. At pH 8.0, ATP would be formed, but if X is added, ATP formation will stop. d. There will be ATP formation in the medium at pH 8.0 and addition of X will enhance it.
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(1 point) A student while studying the anatomy of leaves of four specimens (P - S), observed the following characters: P. Reticulate venation and no bundle sheath. Q. Parallel venation and bundle sheath containing chloroplasts. R. Reticulate venation and bundle sheath containing chloroplasts. S. Parallel venation and bundle sheath without chloroplasts. Identify the type of plants. a. P and R are C4 dicots, while Q and S are C4 monocots. b. P and R are C3 dicots, while Q and S are C3 monocots. c. P and S are C3 dicot and monocot, respectively, while Q and R are C4 monocot and dicot, respectively. d. P and S are C4 dicot and monocot, respectively, while Q and R are C3 monocot and dicot, respectively.
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(1 point) One can determine the age of an oak tree by counting the annual rings of _____________ formed by the _________________. a. primary xylem, apical meristem b. secondary phloem, vascular cambium c. dermal tissue, cork cambium d. secondary xylem, vascular cambium
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(1 point) For measuring the rate of transpiration of a twig using Ganong’s potometer, student A cuts the twig and fits it in the broad end of the water-filled potometer. Student B cuts the twig under water and fits in the broad end of the potometer. Both the students introduce an air bubble in the stem of the
6 potometer, make the apparatus air-tight and start taking readings. What would they observe? a. Both A and B observe air bubble moving towards the twig. b. Both A and B observe no movement of air bubble. c. A observes no movement and B observes movement of air bubble towards the twig. d. A observes movement, while B observes no movement of air bubble towards the twig.
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(1 point) In an experiment, velocity of xylem sap is measured in both small twig as well as main trunk of the same tree over a day. Which one of the following could be the correct graph describing it?
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(1 point) Which of the following graphs correctly depicts the rate of photosynthesis of sun plant (P) and shade plant (Q)? 0 2 4 6 8 Velocity (m/h) 1 2 4 8 10 Time (h) a. 0 2 4 6 8 Velocity (m/h) 1 2 4 8 10 Time (h) 0 2 4 6 8 Velocity (m/h) 1 2 4 8 10 Time (h) c d. 0 2 4 6 8 Velocity (m/h) 1 2 4 8 10 Time (h) b. Trunk Twig
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(1 point) Read the following description: “In these autotrophs, sporophyte is the dominant generation. Gametophyte is also photosynthetic and not dependent on sporophyte for nutrition.” These autotrophs are: a. Bryophytes. b. Pteridophytes. c. Gymnosperms. d. Angiosperms.
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(1 point) A vertical section of an ovule is shown below. The correct ploi
Topic: Conservation of Energy, Oscillations & Waves, Thermodynamics Metodi: Energy Conservation Method, Conservation Laws, Simple Harmonic Motion Analysis, Wave Equation Competenze: Physical Reasoning, Mathematical Modeling Fonte: Testo (PDF) — p.1