A culture of asynchronously growing fibroblasts was analyzed for cell cycle para
ID: 48559 • Letter: A
Question
A culture of asynchronously growing fibroblasts was analyzed for cell cycle parameters. It was determined that the doubling time of the cells is 44 hours, and the times are 2 hours for M, 18 h for G2, 10 h for S.
What proportion of the cells are in M phase?
The cells are fed radioactive thymine for a short period of time (10 min). What proportion of cells incorporate the radioactive thymine as detectable by autoradiography?
After the short pulse the radioactive thymine is removed from the culture. How much time will elapse before radioactive chromosome in M are detected?
What proportion of cells are in G1?
Explanation / Answer
18+2+10=30 so 14 hours for G1
now 2/44= 4 percent of cells arein M phase
10/44=22.7 percent of the cells are in s phase which has thymine in it
18 h because there is a g2 pahse in between
for g1 14/44= 32 percent of the cells are in g1 phase