A human cell in culture takes 24 h to go round the cycle…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A human cell in culture takes h to go round the cycle. Its phases last: G1 h, S h, G2 h and M h.
- How many hours does interphase last?
- What per cent of the cycle is interphase?
- What per cent of the cycle is S phase?
Need a reminder? The key ideaShow
A human cell in culture takes about 24 hours to go round the cycle: G1 about 11 h, S about 8 h, G2 about 4 h and M about 1 h. Interphase is G1, S and G2. S phase raises the DNA from 2C to 4C and gives every chromosome a second chromatid. The number of chromosomes stays 2n.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. G1 h, S h, G2 h, M h. Cycle: h.
Plan. Add the phases of interphase. Then find each share of the whole cycle.
Step 1. Interphase. h.
Step 2. Its share. .
Step 3. S phase. .
Answer: h; ; .
Check. NCERT says that interphase is more than of the cycle. agrees.
Watch out. Books split the h in different ways. A question that gives its own hours must be answered with its hours.
Source. Cooper and Hausman (2007), The Cell: A Molecular Approach, 4th edition, chapter 16; NCERT, Class XI Biology, chapter 10, for the h and the h.
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