8.4 + 8.5 protein synthesis - transcription and translation Flashcards
Key points for transcription
Part of DNA unwinds
Free RNA nucleotides attach
RNA polymerase joins them together
RNA polymerase detaches
Transcription stops
What does DNA helicase do during transcription?
It breaks the H bonds between the 2 DNA strands
Exposed the bases
How many strands act as a template during transcription?
Only one is a template for the formation of mRNA strand
What does RNA polymerase do during transcription?
It joins the free RNA nucleotides together
Forming sugar phosphate backbone of mRNA molecule
What are the free RNA nucleotides attracted to during transcription?
They are attracted to their complimentary exposed bases
When does transcription stop?
When the RNA polymerase reached a stop signal, it detaches and transcription stops
+ polypeptide moves away
What is a stop signal in transcription?
It’s a specific sequence of bases that signals the end of the gene
What is splicing?
The removal of introns from premRNA
What is translation?
The conversion of mRNA into a/a sequence
Production of polypeptides
What is premRNA?
A strand of mRNA in eukaryotes that still contains introns and exons
Key point of translation
mRNA associated with ribosomes
tRNA have a specific a/a
tRNA with an anti codon attaches to the first codon
this repeats for the second codon too
a/a are joined together
Ribosome moves to next codon and does the same thing
Last tRNA detaches
Continued until stop signal
What is the tRNA’s anticodon like?
It’s complimentary to the codon
How are a/a joined together during transcription?
They use energy from ATP
During condensation reactions
by RNA polymerase
What bond does the joining of two a/a make?
It forms a peptide bond
What happens when the ribosome moves to the next codon during transcription?
The previous tRNA detaches
