Oestrogen is a steroid hormone that belongs to a group of female sex hormones called oestrogens.
Steroid hormones are hydrophobic.
Explain why oestrogen can rapidly enter a cell by passing through its cell-surface membrane.
In the cytoplasm, oestrogen binds to a specific oestrogen receptor (ER). An ER is a protein.
Suggest and explain why oestrogen binds to a specific ER.
The binding of oestrogen to an ER changes the shape of the ER. This ER molecule now enters the nucleus and stimulates gene expression.
Suggest how the ER could stimulate gene expression.
The gene that codes for the ER has a variable number of GT repeats. Some studies have shown an association between the number of GT repeats and the risk of developing breast cancer.
Table 1 shows the results of a statistical test from one study.
Table 1
| Number of GT repeats in the ER gene | Probability (P) value |
|---|---|
| ≤15\le 15≤15 | 0.01 |
| ≤16\le 16≤16 | 0.25 |
| ≤17\le 17≤17 | 0.08 |
| ≤18\le 18≤18 | 0.15 |
| ≥19\ge 19≥19 | 0.10 |
What can you conclude from the data in Table 1?
