Lecture 13- transcription in prokaryotes Flashcards
Nucleoid
Bacterial equivalent of a nucleus
Not membrane bound
Contains DNA and proteins
How is DNA arranged in a nucleoid
Assembles in loops and supercoils
Lops contain DNA that is condensed- interacts with positively charged proteins
Transcription
Synthesis of RNS from DNA template
RNA polymerase copies one strand of DNA into RNA
Gene
Region of double stranded DNA that encodes a peptide chain (protein)
Examples functional RNAs coded by genes
Genes encoding tRNA and rRNA
Genes encoding RNAs that help to process mRNA
Start codon for a protein
AUG (Met)
Does AUG have to be at the start of the mRNA?
No, there can be mRNA before the AUG but it will be untranslated
RNA is always synthesised …. to …..
5’
3’
mRNA is longer that the protein coding region because of the 5’ to 3’ ………
untranslated regions
The promoter is…
the control region found at the start of the gene
key region for controlling the transcription of a gene
The point where transcription starts is within the …..
promoter
mRNA is synthesised in the direction from … to ….
promoter
terminator
Anything in the direction of the promoter is ….
upstream
Anything in the direction of the terminator is ….
downstream
Operon
A cluster of genes that are transcribed together to give a single mRNA molecule which encodes multiple proteins
