A receptor has a Kd of 2 nmol/L. The share of the receptors that hold a hormone molecule is H/(Kd +…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A receptor has a Kd of 2 nmol/L. The share of the receptors that hold a hormone molecule is , where is the concentration of the hormone.
- What per cent of the receptors are occupied when nmol/L?
- What per cent are occupied when nmol/L?
- What per cent are occupied when nmol/L?
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. nmol/L.
Plan. Use the formula for each concentration.
Step 1. nmol/L. , which is .
Step 2. nmol/L. , which is .
Step 3. nmol/L. , which is .
Answer: ; ; .
Check. The share rises with the concentration, but never reaches .
Watch out. This is a teaching model of binding. NCERT gives only the idea that the hormone binds to a specific receptor.
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