Regulation of transcription and translation

Control of Gene Expressions 

Cells can be differentiated and undifferentiated.

Differentiation is when a cell becomes specialised to carry out a particular function by the switching on and off of genes.

Transcription Factors

Transcription factors are proteins that bind to a section of DNA adjacent to a gene and either stimulate or inhibit RNA polymerase; therefore stimulating or inhibiting transcription of a gene. 

Oestrogen stimulates transcription of genes in cells which have oestrogen receptors. 

1. Oestrogen is lipid soluble so diffuses across the cell-surface membrane.

2. An inhibitor molecule blocks the binding site to the receptors.

3. Oestrogen binds to the receptor.

4. The binding of the oestrogen to the receptor causes the receptor to change shape and release the inhibitor. 

5. Transcription factor binds with the DNA and begins the process of transcription. 

The role of the transcription factor is to bind to the promoter region allowing the RNA polymerase to transcribe the gene (switching genes on and off).

Control of transcription using Epigenetics

Epigenetic Control is a way of controlling gene expression; without changing the underlying DNA base sequence. The environment can affect the epigenetic control of genes and therefore gene expression. 

Eukaryotes…