Question

Which of the following statements are true? (Choose all that apply)

a. Some Bcl₂ family members promote apoptosis, whereas others inhibit apoptosis.
b. The death-promoting members of the Bcl₂ family include Bcl2 itself.
c. Some death-inhibiting members of the Bcl₂ family inhibit apoptosis by blocking cytochrome c release from mitochondria.
d. Bax and Bak are death-promoting members of the Bcl₂ family that induce the release of cytochrome c from mitochondria into the cytosol.

Answer 1

Statement a is true. Some Bcl₂ family members promote apoptosis, whereas others inhibit apoptosis. Statement b is false. Statement c is true. Some death-inhibiting members of the Bcl₂ family inhibit apoptosis by blocking cytochrome c release from mitochondria. Statement d is true. Bax and Bak are death-promoting members of the Bcl₂ family that induce the release of cytochrome c from mitochondria into the cytosol, which triggers apoptosis.

Step-by-step explanation:

Statement a is true. Some Bcl₂ family members promote apoptosis, whereas others inhibit apoptosis. For example, Bcl-2 and Bcl-xL are anti-apoptotic proteins that inhibit apoptosis, while Bax and Bak are pro-apoptotic proteins that promote apoptosis by inducing the release of cytochrome c from mitochondria.

Statement b is false. Bcl2 itself is an anti-apoptotic protein.

Statement c is true. Some death-inhibiting members of the Bcl₂ family, such as Bcl-xL, inhibit apoptosis by blocking cytochrome c release from mitochondria.

Statement d is true. Bax and Bak are death-promoting members of the Bcl₂ family that induce the release of cytochrome c from mitochondria into the cytosol, which triggers the molecular events leading to apoptosis.