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 organism is classically acid-fast?

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

The answer and the reasoning

B. Mycobacterium tuberculosis

Mycobacterium tuberculosis has mycolic acid-rich cell walls that retain carbol fuchsin during acid-fast staining and resist ordinary decolorization.

Option by option

  • A. Entamoeba histolytica

    Entamoeba is a protozoan parasite.

  • B. Mycobacterium tuberculosis (correct)

    Correct: mycobacteria are acid-fast because of mycolic acids.

  • C. Streptococcus pneumoniae

    S. pneumoniae is a gram-positive diplococcus.

  • D. Candida albicans

    Candida is a yeast.

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 B, Mycobacterium tuberculosis. Mycobacterium tuberculosis has mycolic acid-rich cell walls that retain carbol fuchsin during acid-fast staining and resist ordinary decolorization.

Why is "Entamoeba histolytica" not the answer?

Entamoeba is a protozoan parasite.

Why is "Streptococcus pneumoniae" not the answer?

S. pneumoniae is a gram-positive diplococcus.

Why is "Candida albicans" not the answer?

Candida is a yeast.

What concept does this question test?

It tests Bacteriology in Microbiology. The correct option holds because: Correct: mycobacteria are acid-fast because of mycolic acids.

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.