In a model of a second messenger, each hormone molecule that binds to a receptor leads to 1000…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
In a model of a second messenger, each hormone molecule that binds to a receptor leads to 1000 molecules of cyclic AMP. Each molecule of cyclic AMP switches on 5 enzyme molecules.
- How many molecules of cyclic AMP are made by 10 hormone molecules?
- How many enzyme molecules are switched on by these 10 hormone molecules?
- How many enzyme molecules are switched on for each hormone molecule?
Need a reminder? The key ideaShow
A hormone acts only through a specific receptor in the target tissue. Peptide hormones and adrenaline bind to receptors in the membrane and work through second messengers such as cyclic AMP. Steroid hormones and thyroid hormones pass into the cell, bind to receptors inside, and act on the genes. The fraction of receptors occupied is hormone divided by (Kd plus hormone).
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. cyclic AMP for each hormone molecule. enzymes for each cyclic AMP.
Plan. Multiply step by step.
Step 1. Cyclic AMP. molecules.
Step 2. Enzymes. molecules.
Step 3. For each hormone molecule. enzyme molecules, or .
Answer: ; ; molecules.
Check. The two ways of finding the last answer agree.
Watch out. The numbers are chosen to show the idea. Real cells differ, and many hormones work with much smaller amplification.
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