Cell injury and adaptation: clearance of apoptotic cells: practice question

A Pathology 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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Pathology · Cell injury and adaptation: clearance of apoptotic cells

Sample item

Apoptotic cells are cleared by macrophages without triggering inflammation. Which membrane change on the dying cell acts as the main 'eat me' signal?

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

The answer and the reasoning

C. Phosphatidylserine flipping to the outer leaflet

In apoptosis, phosphatidylserine normally confined to the inner leaflet moves to the outer surface. Macrophages recognise it, directly or through opsonins, and engulf the cell before its contents leak, so no inflammation results.

Option by option

  • A. Exposure of cytosolic cytochrome c

    Cytochrome c is a mitochondrial protein that activates caspases inside the cell.

  • B. Cell-surface display of Fas ligand

    Fas ligand is a death-inducing signal for other cells, not the engulfment marker.

  • C. Phosphatidylserine flipping to the outer leaflet (correct)

    Correct. Externalised phosphatidylserine marks the cell for phagocytosis.

  • D. Loss of surface MHC class I

    MHC class I is relevant to T-cell recognition, not to phagocytic clearance.

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.

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Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is C, Phosphatidylserine flipping to the outer leaflet. In apoptosis, phosphatidylserine normally confined to the inner leaflet moves to the outer surface.

Why is "Exposure of cytosolic cytochrome c" not the answer?

Cytochrome c is a mitochondrial protein that activates caspases inside the cell.

Why is "Cell-surface display of Fas ligand" not the answer?

Fas ligand is a death-inducing signal for other cells, not the engulfment marker.

Why is "Loss of surface MHC class I" not the answer?

MHC class I is relevant to T-cell recognition, not to phagocytic clearance.

What concept does this question test?

It tests Cell injury and adaptation: clearance of apoptotic cells in Pathology. Macrophages recognise it, directly or through opsonins, and engulf the cell before its contents leak, so no inflammation results.

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 Cell injury and adaptation: clearance of apoptotic cells?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology 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.