GATE BT Microbiology PYQs & Answers

Attempt a question, record the concept and assumptions, then check the available answer. Rework mistakes after revising the relevant concepts. Topic tags can overlap; review the question context.

Questions 1–10 of 37. Imported answers require independent review unless marked reviewed.

Topic practice 37 questionsPage 1 of 4

In nitrogen fixation, to reduce nitrogen to ammonia, which one of the following shows the correct order of electron flow?

Your answerChoose one option.

Ferredoxin → reductase → nitrogenase

NADH → reductase → nitrogenase

Ferredoxin → nitrogenase → reductase

Reductase → NADH → nitrogenase

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To determine the viable cell count of a bacterial culture, you have plated 50 μL of a 100-fold diluted sample of the culture on a nutrient agar plate and obtained 20 colonies after overnight incubation. The viable cell count of the culture is _____ CFU mL⁻¹. (answer in integer)

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Koch’s postulate was established by Robert Koch while working on a disease caused by

Your answerChoose one option.

Mycobacterium tuberculosis

Bacillus anthracis

Streptococcus pneumoniae

Bacillus subtilis

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Corynebacterium diphtheriae causes diphtheria in humans, only when this bacterium is infected by

Your answerChoose one option.

phage β

epsilon phage

T4 phage

lambda phage

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Which of the following features is/are used to distinguish Archaea from Bacteria?

Your answerSelect all correct options. You can choose more than one.

Gram-staining

Peptidoglycan in the cell wall

Presence of N-acetylglucosamine

16S rRNA sequences

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Correctly match the Microorganisms with their respective Nutrition and energy requirement.

Microorganisms	Nutrition and energy requirement
P. Photoautotrophs	1. Use organic compounds as a source of energy, hydrogen, electron and carbon
Q. Chemoorganotrophs	2. Use light energy and use CO₂ as their carbon source
R. Chemolithoautotrophs	3. Use light energy and use organic compounds as electron donor and carbon source
S. Photoorganoheterotrophs	4. Oxidise reduced-inorganic molecules as energy and electron source but derive carbon from organic sources

Your answerChoose one option.

P-2; Q-1; R-4; S-3

P-2; Q-1; R-3; S-4

P-1; Q-2; R-4; S-3

P-4; Q-1; R-2; S-3

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The relationship that involves the exchange of nutrients between two different species for their mutual growth is called ________.

Your answerChoose one option.

antagonism

commensalism

parasitism

syntrophism

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Which one of the following bacteriophages has a genome composed of single stranded circular DNA?

Your answerChoose one option.

ØX174

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Match the disease (Column I) with its biological vector (Column II).

Column I　　　　　　　　　Column II P. Chagas disease　　　　　1. Tsetse flies Q. Trypanosomiasis　　　　 2. Mosquitoes R. Leishmaniasis　　　　　 3. Sandflies S. Yellow Fever　　　　　　4. Reduviid bugs

Your answerChoose one option.

P-4; Q-1; R-3; S-2

P-2; Q-3; R-4; S-1

P-1; Q-4; R-3; S-2

P-3; Q-1; R-2; S-4

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The correct sequence of events during bacteriophage infection of a bacterial cell is

Your answerChoose one option.

landing → attachment → tail contraction → penetration and unplugging → DNA ejection

attachment → landing → penetration and unplugging → tail contraction → DNA ejection

landing → tail contraction → attachment → DNA ejection → penetration and unplugging

attachment → tail contraction → landing → penetration and unplugging → DNA ejection

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GATE BT Microbiology PYQs

How to practice Microbiology

Question 17

Question 33

Question 11

Question 12

Question 21

Question 36

Question 15

Question 21

Question 36

Question 20