Gene Expression Part 1 Flashcards
What is contained in the coding gene structure
Promoter
Start and stop codons
Exons and introns
Upstream regulatory region
How does a cell keep control over which genes are expressed or not
Potential regulatory elements
What is gene expression driven by
RNA polymerase 2
What needs to occur for a one to be expressed and switched on
Need a number off
DNA binding proteins
Transcription factors
Promoter region
How can gene expression be fine tunes
By the binding of other DNA binding proteins to distal regions termed upstream enhancer sequence
what do activators do to the sequence
They enhance the sequence and increase expression significantly
What is produced in transcription
mRNA
tRNA
rRNA
What molecule aids in the production of
mRNA
tRNA
rRNA
RNA polymerase
What are the 3 different types of polymerase
RNA polymerase 1
Production of large ribosomal RNA
RNA polymerase 2
Production of mRNA
RNA polymerase 3
Responsible for production of tRNA and the small ribosomal RNA molecule.
Describe the process of transcription
RNA polymerase molecules collide randomly with the DNA in the nucleus and bind with specific DNA sequences called promoter.
The RNA polymerase then opens up a short length of the DNA helix exposing a specific section of DNA on each strand
One stand acts as a template
What are the two types of transcriptional repressors
Interacts with activator - Blocks function
Overlapping binding sites- stops activator from binding.
Describe the process of RNA processing
5’ end is capped of the mRNA molecule
Addition of methylated G nucleotide by removal of a phosphate
And addition of a GMP via guananyl transferase and the addition of a methyl group via methyl transferase
3’ End is cleaved at a specific site and a poly A tail of up to 200 nucleotides os added by poly A polymerase
What is RNA splicing
Where introns are removed
What is translational control
WHere the mRNA associated with ribosomes which translated into a polypeptide chain.
Many ribosomes attach to each mRNA
Define the initiation process of translation
Occur when the intiator of tRNA carrying methionine associated with a small ribisomal unit in association with eukaryotic intiatiation factor 2.
The small ribosomal until recognises the 5’ end of mRNA capped with 2 additional initiation factors and scans the mRNA for a start codon which allows the large subunit to bind.
