A cell makes 4 molecules of beta-galactosidase in a minute when no lactose is present…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A cell makes molecules of beta-galactosidase in a minute when no lactose is present. When lactose is present, it makes molecules in a minute.
- By what factor does lactose raise the output?
- The output without lactose is what per cent of the output with lactose?
Need a reminder? The key ideaShow
In the lac operon, lactose binds the repressor and takes it off the operator, and then the operon is on. In a DNA fingerprint, half of the bands of a child come from its mother. The other half come from its father. So every band of the child must be found in one of the two parents.
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. and molecules a minute.
Plan. A ratio, and a share.
Step 1. (a) times.
Step 2. (b) .
Answer: times; .
Check. The two answers agree: a rise of 500 times means that the old level is of the new one.
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