Transcription and Gene Expression (7.2)
SECTION LINKS: |
NOTES HLHL JEOPARDY GAME REVIEWFor Core MATERIAL and NOTES See Topic 2.7 |
Transcription Regulation and Modification Overview
Transcription seems relatively simple at first look.
The control of transcription is vital to the functioning of our cells. If we cannot control what genes are transcribed and when they are transcribed then the liver cells might start producing substances meant for the kidney or the heart. These could be detrimental to the health of any cell or organsism. The subsequent mRNA that is produced has to be correctly identified and translated as well, hence post-modification.
|
|
Nucleosomes
Nucleosomes occur in Eukaryote Cells ONLY. Composed of:
|
|
Epigenetics, Methylation and AcEtylation
Epigenetics is the study of the chemical tags that attach to our DNA and histones and help turn genes on and off. Scientists now know that epigenetic tags can be influenced by diet, exercise, chemicals in the environment, and may even be passed down generation to generation. Which, if that is the case, means how your parents, even your grandparents, lived actually influences your gene regulation and even your susceptibility to diseases like cancer and heart disease!
|
Methylation and Aceytalation
Two of these chemical tags are methyl groups and acetyl groups.
|
|
|
Promoters, Enhancer, and Transcription Factors
DNA sequences that are not transcribed were once considered “junk”, or left over from evolution. Today we know that much if not all of these sequences are used for regulation of DNA transcription and gene production. Regulation occurs through:
|
|
|
RNA Splicing
Raw mRNA code is spliced, removing the introns from the mRNA sequence
|
|
|
5' Cap and Poly-A TAil
5' Cap7-methylguanosine cap
|
Poly-A TailA series of 50-250 Adenosines are added to the 3’ end of the mRNA (called Poly A tail)
|