Explore topic-wise MCQs in Microbiology.

This section includes 128 Mcqs, each offering curated multiple-choice questions to sharpen your Microbiology knowledge and support exam preparation. Choose a topic below to get started.

1.

Which of the following virus is transmitted by genital route?

A. Papillomaviruses
B. Herpes simplex virus type 2
C. Hepatitis B virus
D. All of these
Answer» E.
2.

Negri bodies are found in cells infected with

A. Paramyxoviruses
B. Vaccinia virus
C. Fowlpox virus
D. Rabies virus
Answer» E.
3.

The uncontrolled proliferation of cells is termed as

A. hyperplasia
B. anaplasia
C. metastasis
D. all of these
Answer» B. anaplasia
4.

The RNA sarcoma viruses, the most strongly transforming viruses may transform which of the following cells in a culture?

A. fibroblasts
B. myoblasts
C. iris epithelial
D. all of these
Answer» E.
5.

Plant viruses penetrate host cells through transient ores called

A. ectodesmata
B. endodesmata
C. cytodesmata
D. protodesmata
Answer» B. endodesmata
6.

Negative strand ssRNA viruses need to have a preformed replicase when they invade a mammalian cell because they

A. use it to terminate transcripts when they copy host cell mRNA
B. have to make a positive strand copy that can be translated
C. use it to modify host enzymes that are recruited for viral replication
D. none of the above
Answer» C. use it to modify host enzymes that are recruited for viral replication
7.

Which of the following reflects the correct order of events that take place during the multiplication of a virus?

A. Attachment, penetration, maturation, biosynthesis, release
B. Penetration, attachment, biosynthesis, maturation, release
C. Attachment, penetration, biosynthesis, maturation, release
D. Attachment, release, biosynthesis, maturation, penetration
Answer» D. Attachment, release, biosynthesis, maturation, penetration
8.

Influenza virus undergoes antigenic shift resulting in major antigenic changes by which of the following mechanisms?

A. Somatic recombination of heavy and light chains
B. Expression of several different capsule types
C. Changing the receptor binding canyon that docks with the host receptor
D. Reassortment of RNA segments from different influenza viruses
Answer» E.
9.

The reovirus and influenza virus contain

A. 10 different segments of dsRNA and 8 different segments of ssRNA respectively
B. 8 different segments of dsRNA and 10 different segments of ssRNA respectively
C. 5 different segments of dsRNA and 7 different segments of ssRNA respectively
D. 7 different segments of dsRNA and 5different segments of ssRNA respectively
Answer» B. 8 different segments of dsRNA and 10 different segments of ssRNA respectively
10.

Which of the following is responsible for a musty or earthy flavor?

A. Actinomycetes
B. Flavobacterium
C. both (a) and (b)
D. Pseudomonas syncyanea
Answer» B. Flavobacterium
11.

Anthracnose is a defect which can be observed as

A. spotting of leaves
B. spotting of seedpods
C. spotting of fruits
D. all of these
Answer» E.
12.

Saprophytic bacteria cause

A. sliminess or souring in piled, wet and heating vegetables
B. brown rot in vegetables
C. black rot in fruits
D. bacterial soft rot
Answer» B. brown rot in vegetables
13.

Pink rots in eggs is caused by the strains of

A. Pseudomonas
B. Pseudomonas fluorescens
C. species of Micrococcus or Bacillus
D. none of the above
Answer» B. Pseudomonas fluorescens
14.

Which of the following is the spike antigen of HIV-I?

A. gp 120
B. gp 140
C. gp 36
D. gp 41
Answer» B. gp 140
15.

The acidity may be described as "aromatic" when

A. Lactic streptococci and aroma forming Leuconostoc species are growing together
B. Streptococcus lactis and other lactis are growing together
C. appreciable amounts of volatile fatty acids are produced by Coliform bacteria
D. all of the above
Answer» B. Streptococcus lactis and other lactis are growing together
16.

Bacterial ropiness in milk is caused by

A. slimy capsular material from the cells usually gums or mucins
B. slimy capsular material from the cells usually proteins
C. slimy capsular material from the cells usually lipids
D. all of the above
Answer» B. slimy capsular material from the cells usually proteins
17.

Which of the cause(s) has/have been suggested for the chill rings in sausage?

A. Oxidation
B. Production of organic acids or reducing substances by bacteria
C. Excessive water
D. all of the above
Answer» E.
18.

An alkaline reaction in milk is caused by the alkali formers bacteria as

A. Pseudomonas fluorescens
B. A. viscolactis
C. both (a) and (b)
D. none of these
Answer» D. none of these
19.

Black spot in meat are produced mainly by

A. Cladosporium
B. Thamnidium
C. Mucor
D. Rhizopus
Answer» B. Thamnidium
20.

The yoghurt is made from

A. Lactobacillus bulgaricus
B. Streptococcus thermophilus
C. S. cremoris
D. mixed culture of (a) and (b)
Answer» E.
21.

Cheese cancer of Swiss and similar cheese is caused by

A. Oospora Crustacea
B. Oospora caseovorans
C. Oospora aurianticum
D. none of these
Answer» C. Oospora aurianticum
22.

Esters like flavors in butter are resulted from the action of

A. P. mephitica
B. Aeromonas hydrophila
C. P. fragi
D. Pseudomonas synxantha
Answer» D. Pseudomonas synxantha
23.

Watery soft rot is found mostly in

A. fruits
B. vegetables
C. cereals
D. all of these
Answer» C. cereals
24.

A viral load test detects the

A. provirus of HIV in infected cells
B. total amount of virus in the infected host
C. number of viruses being released by each infected cell
D. amount of bacteriophage being produced by E. coli cells
Answer» B. total amount of virus in the infected host
25.

Colorless rots in eggs is caused by

A. Pseudomonas alcaligenes
B. Pseudomonas fluorescens
C. both (a) and (b)
D. none of these
Answer» B. Pseudomonas fluorescens
26.

Bulgarian butter milk is made with the help of

A. Lactobacillus bulgaricus
B. Streptococcus lactis
C. Streptococcus thermophilus
D. S. cremoris
Answer» B. Streptococcus lactis
27.

Which of the following microorganism spoil poultry in polyethylene bags?

A. Pseudomonas-achromobacter
B. Alcaligenes
C. hetero-fermentative species
D. catalase negative bacteria
Answer» B. Alcaligenes
28.

The problem(s) associated with development of a vaccine against HIV is/are

A. antibody alone may be insufficient
B. rapid mutation of HIV
C. virus can spread from cell to cell by fusion to produce syncytia
D. all of these
Answer» E.
29.

Cheese with too low an acidity because of the addition of cream or the failure of the starter often is made gelatinous or slimy by

A. Pseudomonas
B. P. fragi
C. Alcaligenes metalcaligenes
D. all of these
Answer» E.
30.

Which of the following species of Clostridium is responsible for formation of dark green to black colours in cheese?

A. Clostridium tyrobutyricum
B. Clostridium sporogenes
C. Clostridium herbarum
D. None of these
Answer» D. None of these
31.

Which of the following (s) is/are responsible for the green patches on the surface of meats under aerobic conditions?

A. P. expansum
B. P. asperulum
C. P. oxalicum
D. All of these
Answer» E.
32.

The cells most oftenly infected by HIV are

A. Null cells
B. CD8 + T lymphocytes
C. CD4 + T lymphocytes
D. None of these
Answer» D. None of these
33.

More spoilage of eggs is caused by

A. bacteria than molds
B. molds than bacteria
C. synergistically
D. none of these
Answer» B. molds than bacteria
34.

Non bacterial ropiness or sliminess in milk and milk products may be due to the

A. stringiness caused by mastitis and in particular by fibrin and leucocytes from the cow's blood.
B. sliminess resulting from the thickness of the cream
C. stringiness due to thin films of casein or lactalbumin during cooling
D. all of the above
Answer» E.
35.

The greening of sausage may appear as a green ring not far from the casing, a green core, or a green surface. The cause of greening is the production of hydrogen peroxide by

A. hetero-fermentative species
B. catalase negative bacteria
C. both (a) and (b)
D. none of these
Answer» D. none of these
36.

Unopened, sliced bacon, packaged in material somewhat highly resistant to oxygen permeability, is spoiled mostly by

A. Lactobacilli
B. Micrococci
C. fecal Streptococci
D. molds
Answer» B. Micrococci
37.

What is the average incubation period for development of AIDS?

A. One year
B. Five years
C. Ten years
D. Twenty years
Answer» D. Twenty years
38.

The commonest opportunistic infection in AIDS patient in India is

A. cryptosporidiosis
B. toxoplasmosis
C. tuberculosis
D. cryptococcosis
Answer» D. cryptococcosis
39.

Pseudomonas nigrifaciens in mildly salted butter may cause

A. black smudge
B. greenish areas
C. pink color
D. none of these
Answer» B. greenish areas
40.

Black mold rot is caused by

A. A.flavus
B. A. niger
C. Trichoderma
D. Trichothecium roseum
Answer» C. Trichoderma
41.

HIV or Human Immunodeficiency Virus is considered unique because each virus contains:

A. more than 100 copies of the viral genome
B. a genome made up of both DNA and RNA components
C. a viral enzyme known as reverse transcriptase
D. sticky proteins that allow it to bind tightly to host cells
Answer» D. sticky proteins that allow it to bind tightly to host cells
42.

The reovirus and influenza virus contain

A. 10 different segments of dsRNA and 8 different segments of ssRNA respectively
B. 8 different segments of dsRNA and 10 different segments of ssRNA respectively
C. 5 different segments of dsRNA and 7 different segments of ssRNA respectively
D. 7 different segments of dsRNA and 5different segments of ssRNA respectively
Answer» B. 8 different segments of dsRNA and 10 different segments of ssRNA respectively
43.

Which of the following characteristics would not be used to classify viruses?

A. Type of cell wall structure
B. Type of nucleic acid
C. Presence of an envelope
D. Symmetry
Answer» B. Type of nucleic acid
44.

Viral matrix proteins are

A. exposed on the surface of the virus
B. found mainly on naked viruses
C. anchor the envelope of enveloped viruses
D. part of the nucleoprotein core of viruses
Answer» D. part of the nucleoprotein core of viruses
45.

The nucleocapsid is covered by an outer membrane like structure called

A. envelope
B. covering
C. membronocapsid
D. all of these
Answer» B. covering
46.

Which type of interferon is produced by virus-infected cells?

A. α
B. β
C. Both (a) and (b)
D. None of these
Answer» D. None of these
47.

Influenza virus undergoes antigenic shift resulting in major antigenic changes by which of the following mechanisms?

A. Somatic recombination of heavy and light chains
B. Expression of several different capsule types
C. Changing the receptor binding canyon that docks with the host receptor
D. Reassortment of RNA segments from different influenza viruses
Answer» E.
48.

Which of the following virus is transmitted by the respiratory route?

A. Rhinovirus
B. Coronavirus
C. Measles virus
D. All of these
Answer» E.
49.

What is the function of positive strand in double stranded RNA viruses?

A. Synthesis of protein
B. Production of ribosomes
C. Both (a) and (b)
D. None of these
Answer» B. Production of ribosomes
50.

Intracytoplasmic inclusion bodies are found in cells infected with

A. Rabies virus
B. Vaccinia virus
C. Fowlpox virus
D. all of these
Answer» E.