Questions and Answers pdf


1. Extra nuclear DNA in E. coli is termed as

(a) F+ factor

(b) sex factor

(c) episome

(d) All of these

Ans. d

2. Smallest cell/organism is that of

(a) vibrio

(b) bacillus

(c) mycoplasma

(d) Rhizobium

Ans. c

3. Bacteria which retain purple colour after staining with Gram stain is

(a) Gram +ve

(b) Gram -ve

(c) trichous

(d) spirillum

Ans. a

4. Which of the following is a rod-shaped bacterium?

(a) Bacillus subtilis

(b) Pneumococcus pneumoniae

(c) Vibrio cholerae

(d) Streptococcus nigricans

Ans. a

5. Bacteria having a tuft of flagella at both ends are called

(a) peritrichous

(b) bitrichous

(c) amphitrichous

(d) atrichous

Ans. c

6. Bacteria which are smallest in size are

(a) cocci

(b) vibrio

(c) bacilli

(d) spirilla

Ans. a

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7. Bacteria, whose cells have only a single curve are known

(a) vibrio

(b) cocci

(c) spirilla

(d) bacilli 

Ans. a

8. Non-photosynthetic, unicellular, cell wall bound spherical or rod-shaped microorganisms usually smaller than 5 micron in size which lack an organised nucleus are called

(a) viruses

(b) bacteria

(c) cyanobacteria

(d) mycoplasma

Ans. b

9. Organisms which have cell but no distinct nucleus are

(a) bacteria

(b) cyanobacteria

(c) Both (a) and (b)

(d) None of these

Ans. c

10. What does the bacterial cells possess in eukaryotic cells?

(a) Photosynthetic pigments

(b) A nucleoid with a circular chromosome

(c) Membrane-enclosed organelles

(d) A 9 + 2 arrangement of microtubules

Ans. b

11. Plasmids

(a) replicate independently of

(b) often contain antibiotic resistance genes

(c) are transferred from one bacterium to another by conjugation

(d) All of the above main chromosome

Ans. d

12. Bacteria were first discovered by (bacteria were for the first time observed by)

(a) A V Leeuwenhoek

(b) Robert Hooke

(c) Robert Koch

(d) Louis Pasteur

Ans. a

13. The largest non-sulphur bacteria are

(a) vibrio

(b) Bacillus subtilis

(c) spirillum 

(d) E. coli

Ans. c

14. Staphylococcus bacterium is a

(a) chain-like colony

(b) plate-like colony 

(c) bunch-like colony

(d) cube-like colony

Ans. c

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15. Which of the following is the size of bacteria?

(a) 2-10µ

(b) 10-15 µ

(c) 50-100µ

(d) 100-200 µ

Ans.  a

16. A spherical bacterium is termed as

(a) vibrio

(b) coccus

(c) bacillus

(d) spirillum

Ans. b

17. What is the general shape of the Bacilli bacteria?

(a) Rod-shaped

(b) Spherical

(c) Spiral

(d) Comma

Ans. a

18. Bacteria having a tuft of flagella at one end are called

(a) peritrichous

(b) monotrichous

(c) lophotrichous

(d) amphitrichous

Ans. c

19. The smallest bacteria measure approximately

(a) 0.5u

(b) 0.05 u

(c) 0.005 u

(d) 0.0005 u

Ans. a

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20. Largest among sulphur bacteria are

(a) Chlorobium

(b) Beggiatoa

(c) Chromatium

(d) Thiobacillus

Ans. b

21. Bacteria differ from other plants in that they do not have

(a) DNA

(b) RNA

(c) cell wall

(d) a well-defined nucleus

Ans. d

22. Which one of the following does not follow the central dogma of molecular biology?

(a) HIV

(b) Pea

(c) Mucor

(d) Chlamydomonas

Ans. a

23. Infectious proteins are

(a) satellite viruses

(b) gemini viruses

(c) prions

(d) viroids

Ans. c

24. What is not true about retrovirus?

(a) DNA has no role in life cycle

(b) There is a gene for RNA dependent DNA polymerase

(c) Genetic material is RNA

(d) They are causative agents for certain cancers

Ans. d

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25. A chemical compound that is found in all viruses is

(a) Only RNA

(b) lipid

(c) RNA or DNA

(d) protein

Ans. c

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26. Bacteriophage kill

(a) fungi

(b) parasite

(c) bacteria

(d) viruses

Ans. c

27. Provirus is

(a) a free virus

(b) a primitive virus 

(c) an integrated viral genome

(d) a free DNA

Ans. c

28. The process which cannot take place in the absence of virus is

(a) transformation

(b) conjugation

(c) translocation

(d) transduction

Ans. d

29. Which of the following is not a viral disease?

(a) AIDS

(b) Smallpox

(c) Tuberculosis

(d) Influenza

Ans. c

30. Which was the virus to be crystallised for the first time?

(a) Cauliflower mosaic virus

(b) Tobacco mosaic virus

(c) Tomato mosaic virus

(d) Influenza virus

Ans. b

31. Average size range of a virus is

(a) 10-30 nm

(b) 20-14,000 nm

(c) 100-1000 nm

(d) 1-10 nm

Ans. b

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32. The main difference between Gram positive and Gram negative bacteria is

(a) cell membrane

(b) cell wail

(c) ribosome

(d) mitochondria

Ans. b

33. Helically coiled-shaped bacteria are called

(a) spirilla

(b) cocci

(c) bacili

(d) vibrio

Ans. a

34. Extrachromosomal material of bacteria is found as

(a) circular DNA

(b) extrachromosomal DNA

(c) plasmid

(d) All of these

Ans. d

35. Bacteria pili are involved in

(a) asexual reproduction

(b) sexual reproduction

(c) saprophytic nutrition

(d) antibiotic resistance

Ans. b

36. One of the following bacteria is a good vector in genetic engineering.

(a) Mycobacterium tuberculosis

(b) Agrobacterium tumefaciens

(c) Salmonella typhimurium

(d) Bacillus amyloliquefaciens

Ans. b

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37. From where most of the antibiotics are extracted?

(a) Algae

(b) Bacteria

(c) Virus

(d) Plants

Ans. b

38. Mesosome in a bacterial cell is

(a) plasmid

(b) connection between two cells

(c) plasma membrane infolding for respiration

(d) None of the above

Ans. c

39. The wall of bacteria consists of

(a) N-acetyl glucosamine

(b) N-acetyl muramic acid

(c) Both (a) and (b)

(d) cellulose

Ans. c

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40. Bacteria found in hot acidic aerobic conditions, are

(a) halophiles

(b) thermoacidophiles

(c) methanogens

(d) rickettsiae

Ans. b

41. Gram-negative bacteria that is not aerobic is

(a) Escherichia

(b) Pseudomonas

(c) Neisseria

(d) None of these

Ans. a

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42. Name the enzyme which hydrolyses murein

(a) peroxidase

(b) lysozyme

(c) tannase

(d) None of these

Ans. c

43. Coliform bacteria on fermentation of carbohydrates yields

(a) acetic acid

(b) lactic acid

(c) formic acid

(d) All of these

Ans. d

44. Protein from which hook and filaments of flagela are composed is

(a) keratin

(b) flagellin

(c) gelatin

(d) casein

Ans. b

45. Germ theory of diseases was putforth by

(a) Edward Jenner

(b) Weismann

(c) Louis Pasteur

(d) Robert Koch

Ans. c