L6 Flashcards
Why do cells differ?
Because they express different genes and express them at different rates.
What does DNA act as a template for? via what process?
RNA via transcription
What process controls how much protein is produced? think rna
The more RNA is transcribed, the more translation that occurs and the more protein production. This also leads to more cell activity.
What does RNA polymerase do?
Transcribes DNA to RNA
Happens in 5’ to 3’
What diff types of polymerase are there?
What does transcription of mRNA require most often?
RNA polymerase I(most rRNA genes), II, III(tRNA)
Req: RNA polymerase II(protein-coding, miRNA)
What is the overview of transcription?
Basal transcription factors (often a complex set req before transcription starts) bind first
RNA polymerase binds w other factors
C-terminal domain is un-phosphorylated
C-terminal domain is phosphorylated + RNA polymerase starts making RNA
What is the process which genes are switched on to make the RNA message?
Transcription
Give 2 clinical examples of lack of transcription?
Fragile-X syndrome - Large ears, learning difficulties, autism
ATRX = alpha-thalassemia(Deficiency of alpha-globin) and mental retardation.
ATRX is a protein which can unwind DNA.
What is the C-terminal likened to and what are its functions?
Assembly line
Co-ordinate modifications of:
Splicing
Capping
Polydenlyation
Why are introns often large?
For regulation, they allow time for translation.
How are introns removed? What can this be referred to as?
Complex of RNAs and spliceosomes(proteins). They’re removed precisely so RNA can make the correct protein when exon joins to exon and codes.
Referred to as splicing
Give 2 clinical examples of incorrect splicing
Cystic fibrosis
Thalassemia - Anemia from 6 months. Also aberrant processing = premature stop codons + lack of protein.
Give 1 clinical example of exon skipping. (shortens the exon length)
Famililial isolated growth hormone deficiency type II- short stature via mutations in the GH-1 gene.
Describe polydenylation of RNA.
Sequences encoded in gemone are transcribed to RNA
Proteins recognise these
RNA cleaved + polyA tail added to 3’ of the 5’ section
= RNA’s introns removed and PolyA tail added so is capped
