Lecture 8 Flashcards
Reading frames?
Possible ways to read the mRNA strand when making codons.
How many reading frames are possible in translation?
3
How long are open reading frames for the gene?
100-300 amino acids.
What components does translation need to proceed?
mRNA, charged tRNA, ribosomes, and translation initiation factors. Aminoacyl-tRNA are also used.
Aminoacyl-tRNA synthetase?
Determines if the correct amino acid is added that binds to the amino acid and tRNA.
Small ribosome unit binds to?
The correct binding point on the mRNA.
Translation steps? (4•)
•small subunit of ribosome binds to the correct binding site in mRNA and initiation factors bind to the 5’ cap.
•the large ribosome subunit attaches with the first tRNA in the peptidyl site (P) to the start codon.
•The second tRNA attaches to the amino-acyl acceptor site (A) and the first peptide bond between the amino acids are made. The most recent amino acid bonds above the later amino acid.
•the first tRNA moves to the exit (E) site and is ejected as the ribosome moves. All other tRNA’s move one site to the left.
What does tRNA mainly consist?
•an anti-codon that pairs up with each codon in mRNA.
What is the directionality of the anti-codon?
3’-5’ which is anti-parallel.
How many aminoacyl tRNA synthetases are there?
20
Wobble effect?
The ribosome may use the first two nucleotides of a codon to bring the correct tRNA.
UTR?
Untranslated region.
Where in the mRNA does UTR occur?
Both ends of the mRNA.
DNA polymerization?
Pyrophosphate?
