Cortisol is a lipid-soluble steroid hormone that plays a major role in the body's response to stress.
Explain why cortisol can rapidly enter a target cell by passing through its cell-surface membrane.
In the cytoplasm, cortisol binds to a specific glucocorticoid receptor (GR). GR is a protein.
Suggest and explain why cortisol binds to a specific GR.
The binding of cortisol to a GR changes the shape of the GR. This hormone-receptor complex then enters the nucleus and stimulates gene expression.
Suggest how the GR complex could stimulate gene expression.
The gene that codes for the GR protein has a variable number of CAG trinucleotide repeats. Some studies have investigated whether there is an association between the number of CAG repeats in this gene and the risk of developing clinical depression.
Table 1 shows the results of a statistical test from one study.
Table 1
| Number of CAG repeats in the GR gene | Probability (PPP) value |
|---|---|
| ≤14\le 14≤14 | 0.45 |
| ≤16\le 16≤16 | 0.18 |
| ≤18\le 18≤18 | 0.03 |
| ≤20\le 20≤20 | 0.08 |
| ≥22\ge 22≥22 | 0.35 |
What can you conclude from the data in Table 1?
