A culture of asynchronously growing fibroblasts was analyzed for cell cycle para
ID: 48441 • 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?
a. 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?
b. After the short pulse the radioactive thymine is removed from the culture. How much time will elapse before radioactive chromosome in M are detected?
c. What proportion of cells are in G1?
Explanation / Answer
answer a) thymine systhensis means the cell will be in s phase i takes 14 hr in g1 and then it will go for s phase
answer b)18 hr because g2 phaseis 18 hrs
answer c)g1 is taking a period od 14 hours
aso if we want to calculate the frequency as the total number of cell s not given what we can do is to take the ratio as 1/2+1/18+1/10+1/14=0.72, now multiply it with any phase and get the proportion
c) 10 cells approx for g1 phase