Epigenetics Flashcards
Gene Expression
The production of a protein using gene encoded information.
Terms for expression of genes and what expression does
Genes can be “switched on” when they are being expressed, or “switched off” when they are not being expressed. When genes are being expressed proteins will be produced from those genes.
Epigenetics
the study of factors that alter gene expression without changing the structure
Examples of environmental factors
Parent actions during lifetime, cell age, time of day, signals from other cells whether the cell is undertaking cell division
How do factors alter gene expression
Do not change the DNA. They interfere with transcription and translation resulting in changes in the proteins produced by the cell.
Acetylation/histone modification
Molecules e.g. acetyl group can attach to a histone tail changing its shape. This alters the way DNA wraps around them.
Acetylation enhances expression since
The acetyl group promotes a loose chromatin structure, allowing access for RNA polymerase and permitting transcription. When there is no acetyl group the chromatin is more compact, prohibiting transcription.
Methylation
Inhibits gene expression as Methyl-based molecules attach to cytosine bases, and they act as an “on/off switch.” This is done as genes can be switched on or off by changing the methylation pattern.
What happens if genes are switch off accidentally during methylation
problems may result eg disease.
Can the methylation pattern be inherited
Methylation pattern can be passed on as cells divide (and is therefore heritable).
