Fonte: gare di altri paesi/India/biologia/inbo2015-Q.pdf · Apri PDF · apri PDF p.1
Cluster: Meccanica
Soluzioni (stessa cartella): · · · · · · · · · · ·
Problema 1
each question
INSTRUCTIONS SHEET – INBO 2015
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 30 questions carrying 1 point each. All 30 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 28 questions with a total of 70 points. The points for the questions in Section 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
1 INDIAN NATIONAL BIOLOGY OLYMPIAD – 2015 SECTION A
CELL BIOLOGY (7 points)
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(1 point) A highly reductionist attribute of a living system is observed in self- replicating molecules. Autocatalytic RNA is the best example of this. However, if a biological system in the form of primordial cell has to be designed from chemical system, in addition to self-replicating molecules, it requires energy capturing and generating systems as well. Which of the following components would be the most important in organizing a self-propagating biological system? a. Enzymes b. Plasma Membrane c. Mitochondria d. Chloroplasts
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(1 point) Yeast artificial chromosomes (YACs) are genetically engineered chromosomes derived from the DNA of yeast, Saccharomyces cerevisiae. YACs are used as cloning vectors to transfer large fragments of DNA. Which of the following is/are essential to generate a yeast artificial chromosome (YAC) vector? I. Telomeric sequences II. Centromeric sequences III. Autonomously replicating sequences
a. III only b. I and III only c. II and III only d. I, II and III
2 3. (1 point) Restriction endonucleases are enzymes which cut DNA at specific sequences. Two samples of DNA (sample 1 and sample 2) of 18kb each were cut using three different restriction enzymes simultaneously. When the digested samples were run on agarose gel, the following pattern was obtained. Note that each DNA sample has one recognition sequence for each of the three enzymes.
Which of the following could explain the results? a. The concentration of sample 1 used is more than the concentration of sample 2. b. Sample 2 seems to be contaminated with DNA from sample 1. c. The sample 2 was loaded much later than sample 1. d. Sample 1 is circular DNA while sample 2 is a linear piece of DNA.
- (1 point) Liposomes are vesicles used to entrap drugs for targeted delivery to specific organs. Following is a schematic representation of a liposome. 1, 2, 3 and 4 would be:
3 2 1 4 Sample loading wells Direction of migration 2kb 7kb 3kb Sample 1 Sample 2 6kb 9kb
3 a. 1: Water soluble drug 2: Water insoluble drug 3: Homing peptide 4: Polar head of lipid b. 1: Hydrophobic drug 2: Hydrophilic drug 3: Water soluble drug 4: Protein coat c. 1: Homing peptide 2: Hydrophobic drug 3: Hydrophilic proteins 4: Polar head groups of proteins d. 1: Hydrophobic drug 2: Phospholipids 3: Hydrophilic drug 4: Hydrophilic proteins
- (1 point) A typical graph obtained for an enzyme catalyzed reaction that takes place in a human body is shown below.
Which of the following correctly represents the same reaction in which no enzyme is used? Broken line represents the enzyme catalyzed reaction for comparison. Velocity Vmax [ Substrate ]
4
- (1 point) In addition to glycolysis, there also exists another “glucose direct oxidation” pathway in the cell cytoplasm. This pathway is depicted below.
Velocity Velocity Velocity Velocity b. Vmax [ Substrate ] c. Vmax [ Substrate ] d. Vmax [ Substrate ] [ Substrate ] Vmax a. DNA Synthesis Glucose-6-PO4 Glucose-6-PO4 dehydrogenase Gluconolactone Ribose PO4 Ribulose PO4 Xylulose PO4 NADP+ NADPH Fatty Acid Synthesis
5 Enzymes of this pathway will be found abundantly in: i. Bone marrow cells ii. Liver cells iii. Adipose tissue iv. Skeletal muscles
a. i and iii only b. iii and iv only c. i, ii and iii only d. ii and iv only
- (1 point) Red blood cells also possess the same pathway that is shown in Question no. 6. What is the role of this pathway in these cells? i. To provide pentose sugars required for nucleic acid synthesis. ii. To provide reducing equivalents required for fat synthesis. iii. To provide extra energy by direct glucose oxidation. iv. To generate NADPH that can provide protection against reactive oxygen species.
a. i and iv only b. iii and iv only c. i, ii and iii only d. iv only
PLANT SCIENCES (5 points)
- (1 point) The ABC model postulates that the organ identity in each whorl of a flower is determined by the combination of the following five genes: Apetala 1 (AP1) Apetala 2 (AP2) Apetala 3 (AP3)
6 Pistillata (PI) Agamous (AG) The table below indicates the normal expression pattern of these genes in the whorls of a wild flower. As shown in the table, the expression of AP1 or AP2 in a whorl leads to the suppression of AG in that same whorl and vice versa.
Which of the following patterns will develop (from outermost whorl to the innermost whorl) if only the activity of genes AP3 and PI is lost? a. Sepals, Petals, Petals, Carpels b. Sepals, Stamens, Stamens, Carpels c. Sepals, Sepals, Carpels, Carpels d. Sepals, Sepals, Petals, Carpels
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(1 point) With reference to the table in the previous question (Question no. 8), which of the following patterns will develop (from outermost whorl to the innermost whorl) if only the activity of genes AP1 and AP2 is lost? a. Petals, Petals, Stamens, Carpels b. Carpels, Stamens, Stamens, Carpels c. Petals, Stamens, Stamens, Carpels d. Stamens, Stamens, Carpels, Carpels
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(1 point) A CAM plant was supplied with 14CO2 in the evening at 7 pm and the radiolabeled carbon (14C) was monitored over time. The correct pathway followed by the 14C will be:
AP3 or PI (B)
AP1 or AP2 (A) AG (C) Sepals Petals Stamens Carpels 1 Outermost whorl 2 3 4 Innermost whorl
7 a. During night: oxaloacetic acid (cytosol) oxaloacetic acid (vacuole) malate (vacuole) During day: malate (cytosol) CO2 (cytosol) carbohydrates (chloroplast) b. During night: oxaloacetic acid (cytosol) malate (cytosol) malic acid (vacuole) During day: malate (cytosol) CO2 (chloroplast) Calvin cycle intermediates (chloroplast) carbohydrates (chloroplast) c. During night: oxaloacetic acid (cytosol) malic acid (chloroplast) During day: CO2 (cytosol) Calvin cycle intermediates (chloroplast) carbohydrates (chloroplast) d. During night: oxaloacetic acid (cytosol) oxaloacetic acid (vacuole) During day: malate (cytosol) Calvin cycle intermediates (chloroplast) carbohydrates (chloroplast)
- (1 point) Assuming that the number of chromosomes in the endosperm of a gymnosperm is 80, the number of chromosomes before and immediately after fertilization in each of the following structures will be:
Structures Before fertilization After fertilization a. Integument 80 160 Cells of archegonia 80 80 Nucellus 160 160 b. Integument 80 80 Cells of archegonia 40 40 Nucellus 80 80 c. Integument 80 80 Cells of archegonia 40 40 Nucellus 40 120 d. Integument 160 160 Cells of archegon
Topic: Conservation of Energy, Nuclear & Particle Physics Metodi: Energy Conservation Method, Conservation Laws, Radioactive Decay Law, Mass-Energy Equivalence Competenze: Physical Reasoning, Mathematical Modeling Fonte: Testo (PDF) — p.1