M2 Protein Synthesis Flashcards
1
Q
Outline the processes of transcription and where it occurs.
A
mRNA copy of the gene is made in the nucleus.
- RNA Polymerase attaches to the DNA. Hydrogen bonds break separating strands and DNA uncoils.
- RNA Polymerase lines up free RNA nucleotides along the template strand and complementary base pairing result in the mRNA being complementary to the DNA template strand.
- RNA Polymerase moves along DNA assembling mRNA strand. Hydrogen bonds between uncoiled strands reform and strands coil back to a double helix.
- When RNA Polymerase reaches a stop codon, it stops making mRNA and detaches from DNA. Leaves via nuclear pores and attached to a ribosome.
2
Q
Outline the processes of translation and where it occurs.
A
Takes place in the ribosome. Amino acids are joined together by a ribosome to make a polypeptide chain.
- mRNA attaches to a ribosome and tRNA molecules carry amino acids to the ribosome.
- tRNA molecule with an anti-codon that is complementary to the start codon on the mRNA, attaches to the mRNA (complementary base pairing).
- A second tRNA molecule attaches to the next codon on the mRNA.
- rRNA, specifically peptidyl transferase catalyses the formation of peptide bonds between those 2 amino acids attached to the tRNA molecules.
First tRNA molecule moves away leaving its amino acids behind. - A 3rd tRNA molecule binds to the next codon.
Process repeats. - Process continues until a sop codon on the mRNA.
Protein/polypeptide chain moves away from the ribosome.
3
Q
A