Question

Cytochrome c is an important molecule in initiating apoptosis in cells. All of the following regarding cytochrome c are true EXCEPT:

A) The release of cytochrome c into the cytoplasm is an important step in apoptosis initiation.

B) The loss of cytochrome c from the electron transport chain blocks ATP synthesis by oxidative phosphorylation.

C) Loss of cytochrome c from the inner mitochondrial membrane results in increased formation of reactive oxygen species.

D) Bax proteins mediate cytochrome c release.

E) Caspases are proteases that increase cytoplasmic levels of cytochrome c.

Answer 1

Answer is:
E) Caspases are proteases that increase cytoplasmic levels of cytochrome c.

Explanation:

A) The release of cytochrome c into the cytoplasm is an important step in apoptosis initiation: Cytochrome c is involved in initiation of apoptosis.

B) The loss of cytochrome c from the electron transport chain blocks ATP synthesis by oxidative phosphorylation: Electron transport chain blocks ATP synthesis by oxidative phosphorylation. Cytochrome c involved in the electron transport chain of mitochondria.

C) Loss of cytochrome c from the inner mitochondrial membrane results in increased formation of reactive oxygen species: Loss of cytochrome c from the intermembrane space in apoptosis form O2 as when cytochrome c is released then respiratory chain reduced as electron flow between Complex III and Complex IV is reduced.

D) Bax proteins mediate cytochrome c release: Bax induces cytochrome c release from the mitochondria.

E) Caspases are proteases that increase cytoplasmic levels of cytochrome c: Caspases cleave substrates such as downstream caspases that leads to cell death.