200+ TOP Microorganism MCQs with Answers

Microorganism Objective Questions with Answers Pdf Download for Freshers Experienced Medical MBBS Students Microorganism Multiple choice Questions. These Objective type Microorganism Questions are very important for campus placement Interviews.

1. Which of the following structures is the smallest?

A. Viriod

B. Hydrogen atom

C. Bacterium

D. Mitochondrion

Answer: B

2. The oldest eukaryotic organisms are considered to be

A. diplomonads like Giardia

B. archaea

C. fungi

D. animals

Answer: B

3. The phospholipids present in cytoplasm membrane of eubacteria is mainly

A. phosphoglycerides

B. polyisoprenoid

C. phospholipoprotein

D. none of these

Answer: A

4. Which were the investigators lived at the same time?

A. Koch and Pasteur

B. Darwin and Woese

C. Van Leeuenhoek and Ricketts

D. Berg and Hooke

Answer: A

5. The unifying feature of the archaea that distinguishes them from the bacteria is

A. habitats which are extreme environments with regard to acidity

B. absence of a nuclear membrane temperature

C. presence of a cell wall containing a characteristic outer membrane

D. cytoplasmic ribosomes that are 70S

Answer: B

6. Mycoplasmas are different from the other prokaryotes by

A. presence of chitin in cell walls

B. presence of murrain in cell walls

C. presence of proteins in cell walls

D. absence of cell wall itself

Answer: D

7. Evolutionary relationships between groups of organisms are determined using which of the following type of information?

A. Comparisons of nucleotide sequences

B. Comparisons of biochemical pathways

C. Comparisons of structural features

D. All of the above

Answer: D

8. Which of the following is not true for eukaryotic cells?

A. Nucleus is bounded by nuclear membrane

B. Chromosomes contain histones

C. Chloroplasts and mitochondria contains 70S ribosomes

D. Gas vacuoles are present

Answer: D

9. Which of the following is not true for prokaryotic organism?

A. Nucleus is not bounded by nuclear membrane

B. Chromosomes does not contain histones

C. 80S ribosomes are distributed in cytoplasm

D. Cell wall contains peptidoglycan as one of the major component

Answer: C

10. Gram staining was introduced by

A. Christian gram

B. Alfred Gram

C. Robertcook

D. Louis Pasteur

Answer: A

11. Which of the following is considered the most unifying concept in biology?

A. Taxonomy

B. Anatomy

C. Genetics

D. Evolution

Answer: D

12. Various bacterial species can be subdivided into

A. subspecies

B. biovarieties

C. serovarieties

D. all of these

Answer: D

13. Living organisms have many complex characteristics. Which one of the following is shared by non-living matter as well?

A. Homeostasis

B. Tissues

C. Reproduction

D. Molecules

Answer: D

14. A newly discovered microscopic structure is hypothesized to be a living organism. Which of the following lines of evidence would support the contention that this organism may be alive?

A. It contains DNA

B. It is made of a single cell

C. It utilizes energy

D. All of these

Answer: C

15. Mycoplasmas, rickettsiae, and chlamydiae are

A. types of fungi

B. small bacteria

C. species of protozoa

D. forms of viruses

Answer: B

 

16. Which of the following structure is absent in eukaryotic cells?

A. Mitochondria

B. Chloroplasts

C. Golgi structure

D. Mesosome

Answer: D

17. Who was the inventor of the Petri dish?

A. R.J. Petri, an assistant of R. Koch

B. A famous French cook

C. Italian glass blower from Petri, Italy

D. None of the above

Answer: A

18. Which one is not studied in microbiology?

A. Bacteria

B. Animal behaviour

C. Fungi

D. Algae

Answer: B

19. A characteristic of protein synthesis in both the archaea and eukarya is

A. transcription and translation are coupled

B. translation is inhibited by diphtheria toxin

C. proteins are synthesized from D-, rather than L-, isomers of amino acids

D. the initiator tRNA is charged with N-formyl-methionine

Answer: C

20. Cell theory includes all of the following except

A. all organisms are composed of one or more cells

B. the cell is the most primitive form of life

C. the cell is the structural unit of life

D. cells arise by division of preexisting cells

Answer: B

21. The five-kingdom system of classification was set up by

A. Louis Pasteur

B. Robert Whittaker

C. Robert Koch

D. Masaki Ogata

Answer: B

22. The membranes of which domains are chemically the most similar?

A. Archaea and Bacteria

B. Bacteria and Eukarya

C. Eukarya and Archaea

D. membranes of all three domains are chemically identical

Answer: B

23. Primary differences between cilia and flagella are

A. arrangement of microtubules

B. length and location of basal bodies

C. how the microtubules are fused to each other

D. number, length and direction of force

Answer: D

24. All membranes of free-living organisms have phospholipid bilayers, but exception is

A. bacteria

B. fungi

C. archaea

D. protozoa

Answer: C

25. All of the following are features of prokaryotes except

A. nitrogen fixation

B. photosynthesis

C. seual reproduction

D. locomotion

Answer: C

26. The phospholipids present in cytoplasm membrane of the archaeo-bacteria is

A. phosphoglycerides

B. polyisoprenoid

C. polyisoprenoid branched chain lipids

D. none of the above

Answer: C

27. Which of the following is/are included in Kingdom Prokaryotae?

A. Bacteria

B. Protozoa

C. Fungi

D. All of these

Answer: A

28. Which of the following may account for the small size of the cells?

A. The rate of diffusion

B. The surface area/volume ratio

C. The number of mRNAs that can be produced by the nucleus

D. All of the above

Answer: D

29. Genetic and biochemical similarities between contemporary cyanobacteria and eukaryotic chloroplasts are accepted to mean that

A. eukaryotes evolved from bacteria

B. eukaryotes evolved from archaea

C. oxygenic photosynthesis first evolved in eukaryotes

D. cyanobacteria arose from chloroplasts which escaped from plant cells

Answer: B

30. Which of the following represents the hierarchy of levels of biological classification?

A. Phylum, kingdom, class, order, genus, species, family

B. Kingdom, phylum, class, order, family, genus, species

C. Kingdom, phylum, family, class, order, genus, species

D. Class, order, kingdom, phylum, family, genus, species

Answer: B

31. The three domain version of life on earth is based on the

A. nucleic acid sequence data

B. morphological traits

C. metabolic traits

D. characteristics of the cell wall

Answer: A

32. The foundation for the germ theory of disease was set down by

A. Robert Koch

B. Ronald Ross

C. Louis Pasteur

D. Walter Reed

Answer: C

33. Most microbial structures and enzymes are composed of

A. lipids

B. proteins

C. carbohydrates

D. lipids and carbohydrates

Answer: B

34. The individual remembered for bringing microbes to the world is

A. Robert Hooke

B. Antony Van Leeuenhoek

C. Robert Koch

D. Masaki Ogata

Answer: B

35. Micro organisms are found in which of the following kingdom of five kingdom concept (Whittaker’s classification)?

A. Monera

B. Protista

C. Fungi

D. All of these

Answer: D

36. The first organism in most natural food chains is

A. a herbivore

B. a decomposer

C. photosynthetic

D. carnivorous

Answer: A

37. The third kingdom, protista, as suggested by E.H. Haeckel includes

A. bacteria

B. algae

C. fungi

D. all of these

Answer: D

38. Eukaryotic cell organelles first emerged

A. from a specialized lineage of cells within the kingdom Protista

B. when prokaryotes engulfed each other and became interdependent

C. when bacteria made their first attempts at reproduction

D. just before the origin of the animal and fungal kingdoms

Answer: B

39. Who discovered the bacteria that cause cholera?

A. Pierre Berthelot

B. Robert Koch

C. Louis Pasteur

D. Rudolf Virchow

Answer: B

40. Prokaryotic microorganism include

A. protozoa

B. fungi

C. bacteria

D. all of these

Answer: C

41. All the following are basic properties of cells except

A. cells have nuclei and mitochondria

B. cells have a genetic programme and the means to use it

C. cells are capable of producing more of themselves

D. cells are able to respond to stimuli

Answer: A

42. Which of the following microorganisms is classified as a member of archaebacteria?

A. Gyanobacteria

B. Methanobacteria

C. Trichomonads

D. Mycoplasma

Answer: B

43. The idea of selective toxicity was first proposed by

A. Antony van Leeuwenhoek

B. Paul Ehrlich

C. Louis Pasteur

D. Alexander Fleming

Answer: B

44. Which of the following sequences has helped in identifying eukaryotes, eubacteria and archeabacterial cell types?

A. Signature sequence

B. Signal sequence

C. Shine-Dalgarno sequence

D. Amino acid sequence

Answer: A

45. Archeal cells usually do not contain peptidoglycan, rather contain pseudo-peptidoglycan which is mainly composed of

A. N-acetylmuramic acid and L-amino acids

B. N-acetylmuramic acid and D-amino acids

C. N-acetyltalosaminuronic acid and D-amino acids

D. N-acetyltalosaminuronic acid and L-amino acids

Answer: D

46. In the three domain system of classification, the traditional bacteria are placed in the

A. eukarya

B. archaea

C. eubacteria

D. none of these

Answer: C

47. One of the reasons for the evolutionary success of the kingdom Monera is that its members are nutritionally diverse. Which of the following(s) is/are the way(s) of obtaining energy?

A. Photoautotrophy

B. Photoheterotrophy

C. Chemoheterotrophy

D. All of the above

Answer: D

48. Carl Woese and his colleague are known for establishing

A. the five kingdom system

B. the three domain system

C. the prokaryote-eukaryote system

D. the plant-animal system

Answer: B

49. Which of the following is not found in the kingdom Monera?

A. Organelles

B. Organized cell structure

C. Ability to reproduce

D. Ability to use energy

Answer: A

50. Which of the following is the most primitive?

A. Virus

B. Eukaryote

C. Archaeon

D. Mitochondria

Answer: C

51. All the following are considered eukaryotes except

A. archaea

B. fungi

C. protozoa

D. humans

Answer: A

52. Which cell type is considered to have the oldest ancestor?

A. Archaea

B. Bacteria

C. Eukarya

D. they all share the same ancestor

Answer: D

53. What is Mycology?

A. Study of viruses

B. Study of nucleic acid

C. Study of bacteria

D. Study of fungi

Answer: D

54. Which of the following organelles contain DNA, divides and possesses some degree of autonomy?

A. Golgi apparatus

B. Ribosome

C. Chloroplast

D. Peroxisomes

Answer: C

55. All of the following individuals contributed to cell theory except

A. Robert Hooke

B. Matthias Schleiden

C. Theodor Schwann

D. Rudolf Virchow

Answer: A

56. Eukaryotic micro organisms include

A. protozoa

B. fungi

C. algae

D. all of these

Answer: D

57. The binomial name of a microbe is composed of

A. its kingdom and genus names

B. its genus name and a species modifier

C. its family and class names

D. its genus and species names

Answer: B

58. Which of the following is a characteristic unique to the ciliates?

A. Use of cilia as a sensory function

B. Presence of both a macronucleus and several micronuclei

C. Both (a) and (b)

D. Possess a light-detecting eye spot

Answer: C

59. Which of the following structure is present in prokaryotic cells?

A. Mitochondria

B. Chloroplasts

C. Golgi structure

D. Mesosome

Answer: D

60. The word cell was first used by

A. Robert Hooke

B. Theodor Schwann

C. Louis Pasteur

D. Ronald Ross

Answer: A

61. What are Blue-Green bacteria called?

A. Acquaobacteria

B. Cyanobacteria

C. Protozoa

D. None of the above

Answer: B

62. The endosymbiosis hypothesis provides an explanation for how

A. eukaryotes developed from prokayotes

B. prokaryotes developed from eukaryotes

C. algae developed from protozoa

D. protozoa developed from algae

Answer: A

63. The Archaea include all of the following except

A. methanogens

B. halophiles

C. thermoacidophiles

D. cyanobacteria

Answer: D

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