multiple choice questions 43

21. What causes bacterial cells to die out at the end of stationary phase?

a) Nutrition depletion.

b) Toxic waste product buildup.

c) Both of them above.

d) Genetic drift.


22. What is the average doubling time of E. coli during log phase.

a) 2-3 min. b) 20-30 min. c) 45 min. d) 50-60 min.


23. What is the primary site of Auxin synthesis?

a) Shoot and Root.

b) Shoot and pith.

c) Root and apical meristem.

d) Shoot and apical meristem.


24. What is the role of abscission acid in plant physiology?

a) Promote vegetative growth and seed dormancy.

b) Promote leaf senescence and apical growth.

c) Burk production and apical growth.

d) Promote stromal closure and seed dormancy.


25. Which phyto-hormone plays important role in pollination?

a) Auxin. b) Gibberrelins. c) Ehthelene.d) Abscissic acid.


26. What is the physiological process leading to fruit ripening?

a) Climacteric. b) Climatic.c) Climax. d) Climactic.


27. Which trans-membrane ion pump plays the central role of stromal opening?

a) Na+H+ATPase. b) Na+K+ATPase. c) K+H+ATPase. d) Na+K+H+ATPase.


28. What is the main mechanism of stromal closure?

a) Eflux of K+ ion to stromal cell during night.

b) Influx of K+ ion to stromal cell during night.

a) Eflux of Na+ ion to stromal cell during night.

b) Influx of Na+ ion to stromal cell during night.


29. Which of the following substance stimulates stromal opening?

a) CO2

b) Glucose.

c) H2O

d) Ca2+ ions.


30. How does auxin decreases the rate of photosynthesis?

a) By killing photosynthetic cells.

b) Promoting transformation of chloroplast into amyloplast.

c) Promoting stromal closure.

d) By inhibiting RuBisCO.


31. Fusion of more than one sperm during fertilization is called:

a) Polygamy.b) Polyspermy. c) Polynomy.d) Polyploidy.


32. Which part of a sperm contains proteolytic enzymes?

a) Golgi aparatus. b) Acrosome.c) Praetosome. d) Lysosome.


33. Which ion efflux like a wave in ovum cell after sperm entry?

a) Na+b) K+ c) Mg2+ d) Ca2+

Ans: D

34. How does the “fast block of polyspermy” works?

a) Depolarization of ova cell membrane caused by Na+ entry.

b) Repolarization of ova cell membrane caused by K+ entry.

c) Repolarization of ova cell membrane caused by Ca2+ entry.

d) Decrease of pH outside of ova cell membrame.


35. After a rod cell is hit by a photon of visible light which isomer is formed?

a) 11-cis ratinol.

b) 22-cis ratinol.

c) All-trans ratinol.

d) 2-methyl rationl.


36. Which receptor is activated by Rhodopsin after its hit by a photon?

a) Serpentine receptor.

b) Transmembrame receptor.

c) G-protein coupled receptor.

d) Leucin zipper containing doman.


37. Which of the following induces oxygenated hemoglobin molecule to release O2?

a) Increased blood pH.

b) Binding of 2,3-BPG.

c) Alanine buildup.

d) Lower CO2 concentration in blood.


38. What is true for any ecosystem?

a) Matter and energy both are recycled in an ecosystem.

b) Matter and energy both flows in unidirectional way in an ecosystem.

c) Matter flows unidirectionally while energy is recycled.

d) Matter is recycled while energy flows in unidirectional way in an ecosystem.


39. Which is the correct form of energy flow in any ecosystem?

a) Primary Producer → Secondary Producer → consumer → Microbes.

b) Primary Producer → Secondary Producer → secondary & tertiary consumer → Microbes.

c) Primary Producer → Primary consumer → secondary & tertiary consumer → Microbes.

d) Producer → Consumer→ Enhancer → Microbes.


40. What energy sources all life depends on?

a) Solar and geothermal.

b) Solar and chemical.

c) Solar and electric.

d) Geothermal and chemical.


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