Q: Which equation best represents the balance of cell survival and cell death signals?

$$\text{Cell Fate} = \text{Pro-death signals} - \text{Anti-death signals}$$

Question 1

Which of the following best describes the role of phosphatidylserine (PS) during apoptosis?

Accepted Answer

PS flips to the outer membrane, signaling macrophages to engulf the apoptotic cell.

Question 2

A patient with a mutation that causes overexpression of BCL-2 proteins is most likely to develop which of the following conditions?

Accepted Answer

Cancer due to insufficient apoptosis.

Question 3

Which of the following events is a hallmark of apoptosis but can also occur in necrosis?

Accepted Answer

DNA fragmentation into nucleosome-sized pieces.

Question 4

During the intrinsic pathway of apoptosis, which sequence of events occurs?

Accepted Answer

Bax forms pores in mitochondria → cytochrome c release → caspase-9 activation → caspase-3 activation

Question 5

Which of the following is NOT a feature of necrosis?

Accepted Answer

Genetically controlled, single-cell death

Question 6

A researcher observes that cells are dying in a tissue culture, but there is no inflammation and the cells are being engulfed by phagocytes. Which type of cell death is most likely occurring?

Accepted Answer

Apoptosis

Question 7

Which caspase is primarily activated in the extrinsic pathway of apoptosis?

Accepted Answer

Caspase-8

Question 8

In the context of cell death, what is the function of MLKL during necroptosis?

Accepted Answer

MLKL forms transmembrane pores, leading to cell membrane rupture.

Question 9

Which equation best represents the balance of cell survival and cell death signals?

Accepted Answer

$$	ext{Cell Fate} = 	ext{Pro-death signals} - 	ext{Anti-death signals}$$

Question 10

A cell exposed to oxidative stress and low ATP levels is most likely to undergo which type of cell death?

Accepted Answer

Necrosis

Question 11

Which of the following statements about autophagy is TRUE?

Accepted Answer

Autophagy is a survival mechanism but excessive autophagy can cause cell death.

Question 12

Which process is most important for separating digits during embryonic development?

Accepted Answer

Apoptosis

Question 13

A cell loses its attachment to the extracellular matrix (ECM). What is the most likely outcome?

Accepted Answer

The cell will undergo apoptosis (anoikis).

Question 14

Which of the following is a function of caspase-3 in apoptosis?

Accepted Answer

Caspase-3 cleaves structural proteins during the execution phase.

Question 15

Which of the following best explains why inflammation is triggered during necrosis but not apoptosis?

Accepted Answer

Necrosis involves cell membrane rupture and release of cell contents, while apoptosis is contained and cleared by phagocytes.

Question 16

A scientist treats cells with a ligand that binds to the TNF receptor. Which pathway is most likely activated?

Accepted Answer

Extrinsic apoptosis pathway

Question 17

Which of the following is a mechanism by which procaspases are activated?

Accepted Answer

Procaspases are activated by cleavage, conformational change, or proximity.

Question 18

A cell is exposed to toxic proteins that cause internal stress. Which pathway of apoptosis is most likely activated?

Accepted Answer

Intrinsic mitochondrial pathway

Question 19

Which of the following is a specialized form of cell death that results in the formation of protective layers in skin and hair?

Accepted Answer

Cornification

Question 20

A cell is exposed to both pro-apoptotic and anti-apoptotic signals. Which equation best predicts whether the cell will survive or die?

Accepted Answer

$$	ext{Cell Survival} = 	ext{Anti-apoptotic signals} - 	ext{Pro-apoptotic signals}$$

Cell Death: Mechanisms, Pathways, and Biological Significance

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