International Biology Olympiad Practice Problems 2015

1. The correct order in terms of molecular weight is
(a) DNA < fRNA < mRNA < insulin
(b) tRNA < mRNA < rRNA < DNA
(c) rRNA < insulin < cDNA < Z-DNA
(d) insulin < B-DNA < cDNA < Z-DNA
(NSEB 2009)
2. Plant of genotype AaBBCc was cross pollinated with another having the genotype aaBbcc. If all genes involved have complete dominance, the phenotypic ratio in the first generation plants will be
(a) 1 : 2 : 1 (b) 1 : 3 : 3 : 9
(c) 1 : 1 : 1 : 1 (d) 1 : 1 : 1 : 1 : 1 : 1
(NSEB 2012)
3. Which of the following treatments will not cause denaturation of most proteins?
(a) Transfer from aqueous to organic solvent
(b) Addition of electrolyte
(c) Agitation of the solution
(d) Addition of strong acid (NSEB 2009)
4. The indirect development in insects is because of
(a) abundance of food in water
(b) lack of stored food in eggs
(c) spiral cleavage of zygote
(d) short life span of adults. (NSEB 2009)
5. Leber’s optic neuropathy is a disease caused by a mutation in mitochondrial DNA. As a genetic counseller, what will you advise a couple with healthy husband and wife with this disease?
(a) Their children would suffer from the disease irrespective to gender.
(b) If daughter is born, she would not be suffering from the disease.
(c) If they have a son, he would be suffering from the disease.
(d) Their children are not likely to suffer from the disease irrespective of gender. (NSEB 2009)
6. As part of a student project, Sheela surgically made a full cut in the hypothalamic hypophysial tract in pregnant rabbits and studied the physiological effects on different tissues/organs. Which of the following should be expected?
(i) Formation of large volume of dilute urine
(ii) Reduced synthesis of milk by the mammary gland
(iii) Increased heart rate
(iv) Difficulty in parturition
(a) (i) and (ii) (b) (ii) and (iii)
(c) (iii) and (iv) (d) (i) and (iv)
(NSEB 2009)
7. The correct statements about respiration are
(i) In cockroach gaseous exchange occurs mainly between tracheoles and haemolymph
(ii) Increase in inspiratory capacity does not involve an increase in tidal volume
(iii) Partial pressure of oxygen in blood is less than that in alveoli
(iv) Chloride shift in erythrocytes maintain the ionic balance
(a) (i) and (ii) (b) (i), (iii) and (iv)
(c) (i), (ii) and (iv) (d) (ii) and (iii)
(NSEB 2009)
8. Following graph was obtained when rate of K* uptake by roots of growing seedlings was measured at different temperatures. The limiting factor/s at region P and Q is/are

(a) time and rate of metabolism respectively
(b) temperature and time respectively
(c) rate of metabolism
(d) temperature (NSEB 2009)
9. In an experiment, one population of copepod females was fed with diatoms while another one was fed with dinoflagellates and number of eggs hatched was monitored for 10 days.
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The graph indicates that
(a) diatoms are killing female copepods.
(b) diatoms are useful for sustaining copepod populations.
(c) older female copepods produce less viable eggs.
(d) the diatoms are toxic for eggs. (NSEB 2014)
10. Select the statement related to the effect of ethylene
(i) Promotes lateral swelling of stem
(ii) Inhibits elongation of cells
(iii) Causes loss of sensitivity of stem to gravitropic stimuli
(iv) Loosens cell wall
(v) Delayed leaf senescence
(a) (i), (ii) and (v) (b) (i), (ii) and (iii)
(c) (ii), (iv) and (v) (d) (i), (iv) and (v)
(NSEB 2012)
11. Macrophages are white blood cells that phagocytose any foreign body while plasma cells are effector B cells that produce antibodies. When these two cell types are activated, the predominant organelle at work will be respectively
(a) Rough endoplasmic reticulum and Smooth endoplasmic reticulum
(b) Golgi bodies and lysosomes
(c) Lysosomes and Rough endoplasmic reticulum
(d) Peroxisomes and lysosomes (NSEB 2012)
12. A minimum ratio of transpiration to photosynthesis will be observed on a
(a) humid and cloudy day
(b) humid day and sunny day
(c) sunny day with no winds
(d) sunny day with strong winds. (NSEB 2006)
13. The diagram depicts the mechanism of opening of stomata. Identify X and Y.
1
(a) PEP and malate (b) malate and PEP (c) pyruvate and NAD (d) NAD and pyruvate.
(NSEB 2006)
14. Of the homologous pairs of animals that represent placental on mainland and marsupial in Australia, which one is erroneous?
(a) Mole-marsupial mole
(b) Wolf-tasmanian wolf
(c) Bat-wombat
(d) Flying squirrel-flying phalanger. (NSEB 2006)
15. With increase in the total leaf area of a plant, there will be a corresponding increase in the
(a) number of metaxylem vessels
(b) cross sectional area of phloem
(c) xylem : phloem ratio
(d) number of protoxylem vessels. (NSEB 2006)
17. What is not an effect of global warming?
(i) Increased capacity of air to accommodate moisture.
(ii) Altered wind movement pattern.
(iii) Increased frequency of extreme events (flood, drought, etc.)
(iv) Altered range of disease vectors, pathogens, etc.
(a) (i) only (b) (ii) and (iv)
(c) (i) and (ii) (d) (iv) only
(NSEB 2006)
18. Dietary deficiency of this mineral causes rickets in children.
(a) Iodine (b) Zinc
(c) Potassium (d) Iron. (NSEB 2006)
19. Of various factors concerning leaf, the increasing magnitude of influence on photosynthesis is
(a) Leaf angle < leaf age < orientation of chloro- phyllose tissue.
(b) Leaf age < leaf angle < orientation of chloro- phyllose tissue.
(c) Leaf angle < orientation of chlorophyllose tissue
< leaf age.
(d) Leaf age < orientation of chlorophyllose tissue
< leaf angle.
(NSEB 2006)
20. Which of the following bacteria can form colonies on a solid medium containing KH2P04, MgS04-7H20, NaCI, mannitol and CaC03?
(a) Rhizobium (b) Escherichia
(c) Azotobacter (d) Nitrosomonas
(NSEB 2006)
21. A long day plant with critical day length of 14 hrs will flower under which of the following treatments?
(a) 7 hrs light-2 hrs darkness-3 hrs light-5 hrs darkness-7 hrs light
(b) 5 hrs light-9 hrs darkness-8 hrs light-2 hrs darkness
(c) 11 hrs darkness-13 hrs light
(d) 6 hrs light-6 hrs darkness-7.5 hrs light-4.5 hrs darkness (NSEB 2009)
22. In a typical angiosperm anther, 1000 pollen grains were found in each pollen sac. How many meiotic divisions would have occurred in the microspore mother cells before these pollens were formed?
(a) 2500 (b) 1000
(c) 250 (d) 100 (NSEB 2009)
23. Different microorganisms taking part in nitrogen cycle are
(i) Rhizobia in root nodules
(ii) Ammonifying bacteria
(iii) Nitrifying bacteria
(iv) Denitrifying bacteria
Which of them work strictly under anaerobic conditions?
(a) only (iv) (b) (i) and (iv)
(c) (i), (ii) and (iv) (d) none of these
(NSEB 2009)
24. Considering size, which of the following series is the most appropriate?
(a) bacteria > viruses > yeast
(b) hornworts > mosses > liverworts
(c) smooth muscle cell < striated muscle cell < cardiac muscle cell
(d) platelets < human erythrocytes < human eosinophils
(NSEB 2009)
25. A few statements about algae and bryophytes are given below. The correct statements, is/are
(i) Bryophytes are found in terrestrial habitats while algae are not.
(ii) Bryophytes are better adapted to conserve water than algae.
(iii) Bryophytes and algae need aquatic media for reproduction.
(iv) Bryophytes and algae have short-lived gametophytic generation.
(a) (i) and (ii)
(c) (i), (iii) and (iv)
(b) (i), (ii) and (iii)
(d) only (iii)
(NSEB 2009)
Answers
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