Gene Expression - Transcription Flashcards
What is gene expression?
The flow of genetic information from DNA to protein.
What is the pathway for gene expression? (5)
DNA-RNA-Mature RNA-Protein-Final Protein
What is the process of transferring DNA to RNA?
Transcription
What is the process of transferring RNA to Protein?
Translation
What is a gene?
A segment of DNA that is transcribed into RNA
Transcribe this DNA strand into RNA:
5’-CTGCC-3’
3’-GACGG-5’
5’-CUGCC-3’
What are the two types of RNA?
Informational (contains a message of amino acids and proteins) and functional (rRNA, tRNA, snRNA and scRNA)
What is a UTR?
Untranslated Region - The ends of a gene that aren’t translated but are required for translation
What is the -35 sequence for?
Initial recognition
What is the -10 sequence for?
The melting reaction, turning the closed complex into an open complex
What is a rho-factor?
a hexomere consisting of six identical subunits
What does a rho-factor do?
Using helicase activity, rho factor unwinds DNA to RNA
What is a rho-independent terminator made from?
An inverted repeat of A’s - folds into a hairpin loop
What is the difference between an open and closed complex?
An open complex is unwound DNA where a closed complex is wound.
Which end are new bases added to?
3’
What does RNA Polymerase II do?
Synthesises RNA in prokaryotes
What occurs in rho-dependent termination? (2)
Rho-factor binds at rut site and moves towards the 3’ end. Using helicase activity the rho-factor unwinds the DNA-RNA hybrid and releases RNA.
What occurs in rho-independent termination? (3)
Rho-independent termination is made of an inverted repeat of A’s which is transcribed into a hairpin loop. Straight after the hairpin loop DNA and RNA are bound together by A-U pairing. This weaker pairing destabilises the DNA-RNA hybrid which separates, terminating transcription.
