Chapter 21, Problem 14RTC

Summary Introduction

(a)

To write:

What will happen to the apoptosis if CED-9 is functional and CED-3 is nonfunctional?

Introduction:

CED-9 and CED- are proteins that regulate the apoptotic cycle. CED-3 is a positive regulator of programmed cell death while CED-9 regulates it negatively.

Summary Introduction

(b)

To write:

Effect of active Bax and cytochrome c and nonfunctional caspase-9 on apoptosis.

Introduction:

Bax promotes apoptosis, however its overproduction can induce cell death. Cytochrome c is present in the membranes of the mitochondria and its release into the cytosol due to overexpression of Bax leads to apoptosis. However the cell death occurs by caspase-9 mediated pathway.

Summary Introduction

(c)

To write:

Effect of inactive PI-3 kinase and active Bad on apoptosis.

Introduction:

A non-phosphorylated Bad can bind to Bcl-2 proteins and inhibit their anti-apoptotic activity in the absence of trophic factors. However an activated Bad (phosphorylated) cannot bind to the Bcl-2 proteins. PI-3 kinase activates Akt kinase which helps in the phosphorylation of Bad proteins.