Question

Analyze the data. Investigators discovered a new member of the Bel family. To determine the function of this new Bcl protein, the investigators used cell free extracts. They measured the levels of apoptosis in the cells by measuring the activation of caspase 9 in the cells and determined the effect of addition of the novel Bcl protein to the extracts. The results are shown in Figure A. (the numbers indicate the microgram amount of the novel Bcl protein added to the extracts). Novel Bcl protein 0 0.2 0.5 1 1.5 ug Procaspase-9 Cleaved caspase 9 a) Using the data above, do you think the novel Bcl protein is a death inhibitor or a death inducer? Why? (3 pts) To determine how the novel Bcl protein functions, the investigators expressed the novel Bcl protein under a galactose promoter in cells. Then they broke open the cells and centrifuged them to pellet the larger organelles (such as the mitochondria) and separate them from the cytosol (supernatant). The investigators then used Western blot analysis to determine the levels of cytochrome c in the pellet and supernatant in cells containing vector only, and in cells containing Bel protein grown with and without galactose. Novel Bcl protein Vector galactose Cytoc Sup Cytoc Pellet b) What role does cytochrome c play in apoptosis? (you don't need the data to answer this question) 2 pts c) Using the data above, explain the mechanism used by the novel Bcl protein to affect apoptosis. (3 pts)

Answer 1

A) the bcl protein is a death inducer or apoptosis inducer. With treatment of increased concentration of novel bcl protein, the procaspase 9 level decreased and cleaved capase 9 level increased which indicates that the cell has been destined to apoptosis.

B)when a cell enters is destined to apoptosis, the cytochrome c is released into cytosol and cytosolic cytochrome level increases that increases the apoptosis

C) in the sueprnatent cytochrome c level increased which means that novel bcl protein increases cytosolic cytochrome c to iduce apoptosis