Bacteriology: practice question

A Microbiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Microbiology · Bacteriology

Sample item

What bacterial structure contains lipopolysaccharide?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Outer membrane of Gram-negative bacteria

Lipopolysaccharide is a major component of the outer membrane of Gram-negative bacteria and its lipid A portion contributes to endotoxin effects.

Option by option

  • A. Flagellar filament

    Flagella are motility structures.

  • B. Peptidoglycan of Gram-positive bacteria

    Gram-positive organisms lack outer membrane.

  • C. Outer membrane of Gram-negative bacteria (correct)

    Correct: Gram-negative outer membrane contains LPS.

  • D. Capsule of all bacteria

    Capsules vary and are not LPS.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Microbiology questions

Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is C, Outer membrane of Gram-negative bacteria. Lipopolysaccharide is a major component of the outer membrane of Gram-negative bacteria and its lipid A portion contributes to endotoxin effects.

Why is "Flagellar filament" not the answer?

Flagella are motility structures.

Why is "Peptidoglycan of Gram-positive bacteria" not the answer?

Gram-positive organisms lack outer membrane.

Why is "Capsule of all bacteria" not the answer?

Capsules vary and are not LPS.

What concept does this question test?

It tests Bacteriology in Microbiology. The correct option holds because: Correct: Gram-negative outer membrane contains LPS.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Bacteriology?

Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Then use the flashcards and the other Microbiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.