Module 2 Section 3 - Transcription and Translation Flashcards
When does transcription start
When RNA polymerase attaches to the DNA double helix at the beginning of the gene
What happens during transcription
An mRNA copy of a gene is made in the nucleus
What breaks between the two DNA strands
The hydrogen bonds between the 2 DNA strands in the gene break, separating the strands and the DNA molecule uncoils
After the DNA molecule uncoils what happens
One of the strands is used to make a mRNA copy
RNA polymerase lines up free RNA nucleotides along the template strand, what happens next?
Complementary base pairing means that the mRNA strand ends up being a complementary copy of the DNA template strand.
Once the RNA nucleotides have paired up with their specific bases on the DNA strand, what happens
They are joined together, forming an mRNA molecule
The RNA polymerase moves along the DNA…..
Separating the strands and assembling the mRNA strand
What happens to the hydrogen bonds once the RNA polymerase passes by
The hydrogen bonds between uncoiled strands of DNA re-form and the strands coil back into a double helix
What happens when RNA polymerase reaches a stop codon
It stops making mRNA and detaches from the DNA
What happens to the mRNA after detaching from the DNA
It moves out the nucleus through a nuclear pore and attaches to a ribosome in the cytoplasm where the next stage of protein synthesis takes place
What is the second stage of protein synthesis called
Translation
What is the first stage of protein synthesis called
Transcription
Where does translation occur
At the ribosomes in the cytoplasm
What happens during translation
Amino acids are joined together to make a polypeptide chain following the sequence of codons carried by the mRNA
What does the mRNA first do
It attaches itself to a ribosome and tRNA molecules carry amino acids to the ribosome
