Gene Expression Responds Dynamically to Environmental Signals
- This is the process where information from a gene is used to synthesize functional products, such as proteins.
- This then determines an organism's traits.
Hormonal Regulation: The Role of Oestrogen
Definition
Hormones
Hormones are chemical messengers that travel through the bloodstream to regulate various physiological processes.
- Oestrogen, a steroid hormone, plays a critical role in the female reproductive system, influencing the expression of specific genes.
- Remember, oestrogen’s ability to regulate gene expression is tissue-specific.
- It affects only cells with oestrogen receptors, such as those in the uterus, breast, and bone.
Biochemical Regulation: The Lac Operon in Bacteria
- In prokaryotes like Escherichia coli, gene expression is tightly regulated to conserve energy and resources.
- A cluster of genes under the control of a single promoter, allowing coordinated regulation.
The Lac Operon is A Model of Gene Regulation
- The lac operon consists of three structural genes:
- lacZ: Encodes β-galactosidase, an enzyme that breaks down lactose into glucose and galactose.
- lacY: Encodes permease, a protein that transports lactose into the cell.
- lacA: Encodes transacetylase, an enzyme with a less well-understood role.
- These genes are controlled by a promoter, an operator, and a regulatory gene ($lacI$) that produces a repressor protein.
