The Indian National Biology Olympiad (INBO) is an annual competition that shines a spotlight on the exceptional biology talent of young students in India. Conducted by the Homi Bhabha Centre for Science Education (HBCSE), the INBO serves as the first step for students aspiring to represent India at...
Indian Olympiad Qualifier in Biology (IOQB) 2021-2022
conducted jointly by
Homi Bhabha Centre for Science Education (HBCSE-TIFR)
and
Indian Association of Physics Teachers (IAPT)
Part II: Indian National Biology Olympiad (INBO)
Homi Bhabha Centre for Science Education (HBCSE-TIFR)
INSTRUCTIONS
The question paper is divided into Sections A and B. All answers should be written in the
answer booklet only which will be collected at the end of the examination. The question
paper need not be submitted to the examiner.
Before starting, ensure that you have received a copy of the question paper containing a
total of 25 numbered pages.
Section A
Section A consists of 21 questions carrying 1 point each.
All 21 questions are of multiple choice type, with only one correct answer for each
question.
Mark the correct answer with ‘✔’ in the answer booklet 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 29 questions with a total of 79 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: SECTION A: 3X – Y
SECTION B: 3X
********
, SECTION A
CELL BIOLOGY (7 points)
1. (1 point) Well-defined pores in the nuclear membrane mediate the tightly regulated bi-
directional transport between the nucleus and cytoplasm. The green fluorescent protein
(GFP) is smaller than ~40kDa and can pass freely through these pores. In an experiment,
cells were incubated with GFP and then treated with reagent ‘X’. Visualization of these cells
showed a strong signal for GFP in the cytoplasm. The following statements are made
regarding the possible mode/s of action of ‘X.’
I. Blocking the nuclear pores.
II. Inhibition of the active import process.
III. Increased affinity of GFP for a histone protein.
IV. Inhibition of the export process.
Pick the correct option.
a. Only I b. Only II and III
c. Only I, III, and IV d. Only I, II, and III
2. (1 point) Cells respond to contacts and soluble cues from neighboring cells by the process of
cellular signalling. The cell signalling must involve a stimulus / ligand / signal, a plasma
membrane receptor, and signalling proteins downstream of the receptor. If a receptor-bearing
cell fails to signal, which among the following could be the reason/s for the lack of
signaling?
i. Receptor lacking the extracellular domain.
ii. Receptor lacking the intracellular domain.
iii. Exclusively intracellular nature of the stimulus.
iv. Overexpressed positive-signalling-pathway proteins.
Options:
a. i and iii only b. ii and iii only
c. iv only d. i, ii and iii
3. (1 point) Intermediate filaments (IFs) are a type of cytoskeletal elements found inside cells.
When a cell undergoes mitosis, IFs disassemble by the process of phosphorylation of IF-
constituent proteins. If a cell is treated with phosphatase (capable of removing phosphate)
inhibitor and stages of the cell cycle are assessed, which one of the following statements
would be true? Note: A population of cells not treated with phosphatase inhibitor served as
the control (untreated sample).
a. There will be more cells in mitosis compared to that in the untreated sample.
b. There will be fewer cells in mitosis than in the untreated sample.
c. There will be no difference in the number of cells in various stages of cell cycle between
phosphatase treated and untreated samples.
d. Cells cease to grow and will not divide due to this inhibition.
1
, 4. (1 point) The flowchart below indicates the formation of Spermatozoa from Spermatogonia
following division (meiosis and mitosis) and maturation events. These events are listed as I
to IV, and the ploidy levels of some stages are mentioned in the parentheses.
Pick the option which correctly matches each event.
a. (I) - Maturation, (II) - Meiosis, (III) - Maturation, (IV) - Mitosis
b. (I) - Mitosis, (II) - Meiosis, (III) - Mitosis, (IV) - Maturation
c. (I) - Meiosis, (II) - Mitosis, (III) - Mitosis, (IV) - Maturation
d. (I) - Maturation, (II) - Meiosis, (III) - Mitosis, (IV) - Mitosis
5. (1 point) The addition of a natural product to a growing monolayer of cells has been found to
exclusively inhibit nuclear import. This treatment will most potently affect which one of the
following processes?
a. mRNA export and fresh protein synthesis.
b. Cellular signalling leading to mRNA formation.
c. Synthesis of rRNA and new ribosomes.
d. Nuclear pore distribution on the nuclear envelope.
6. (1 point) A sample of plasmid DNA was divided into 3 tubes M, N and O. Restriction
enzyme (RE) 1 was added to tube M; RE 2 was added to tube N and a mixture of RE 1 and
RE 2 was added to tube O. After incubation of the tubes for 1 hour at 37 °C, the samples from
the tubes were loaded into agarose gels and electrophoresis was carried out. The relative
positions of the DNA fragments after electrophoretic separation are shown. Note that both
enzymes had at least one restriction site on the treated DNA molecule. (Arrow indicates
direction of migration of bands.)
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