Question

1) You are examining two mutants where you are able to quantify the amount of DNA - shown below. One of these mutants has a loss of function in the APC and the other mutant has a loss of function in Ras. Match the graph with the mutant and EXPLAIN what about the graphs indicated that it was this mutant - process of elimination is not acceptable.

1) You are examining two mutants where you are able to quantify the amount of DNA- shown below. One of these mutants has a loss of function in the APC and the other mutant has a loss of function in Ras. Match the graph with the mutant and EXPLAIN what about the graphs indicated that it was this mutant-process of elimination is not acceptable. WT A B Percent of cells 25% 50% 75% 100% 0 25% 50% 75% 100% 25% 50% 75% 100% O 40 2- 2. 4n 2n Mos of DNA Mass of DNA Mass of DNA

Answer 1

1. The Ras protein is responsible for activating various other proteins which are essential for cell division, proliferation and survival. So the Ras protein causes cell division or is highly active in the 'S' pahse of the mitosis.

Now if the mutant has loss of function in Ras it means that the cell 'S' phase is haulted or the cell division rate is very low which actually looks like the 'B' image where the mass of the DNA is very low than the wild type.

So the 'B' mutant has loss of function of Ras protein.

2. The APC or Anaphase-promoting complex as the name suggests it is responsible for cell to enter the 'Anaphase' of mitosis.

Now if the cell has loss of function of APC it will lead the cell to arrest in anaphase which means thet the duplicated chromosomes (4n Chromosome) can not be seperated properly and can not be divide in two different cell. So it will looks like the image 'A' where the 4n chromosome is very low.

So the 'A' mutant has loss of function of APC.