A student in Lisbon grows yeast. A yeast cell goes round the cycle in about 90 min…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A student in Lisbon grows yeast. A yeast cell goes round the cycle in about min. A human cell in culture takes about h. Suppose that every yeast cell goes on dividing and none dies.
- How many cycles does a yeast culture complete in h?
- How many yeast cells come from one yeast cell in h?
- How many cells come from one human cell in h?
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. Yeast cycle: min. Human cycle: h min.
Plan. Divide the time by the length of the cycle. Then double the cells in each cycle.
Step 1. Cycles of yeast. .
Step 2. Yeast cells. cells.
Step 3. Human cells. One cycle of h gives cells.
Answer: cycles; cells; cells.
Check. The yeast cycle is times shorter, so it completes cycles in the time of one human cycle.
Watch out. In real cultures the cells run out of food, so the number is a limit and not a prediction.
Source. NCERT, Class XI Biology, chapter 10 (yeast about min; human cell about h).
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