Translation Flashcards
Describe the Eukaryotic ribosome.
The ribosome is the site of translation. 80s Eukaryotes are composed of 60s and 40s subunits, and is made of protiens and rRNA. There are 3 tRNA binding sites: A site, P site, and E site.
Describe the prokaryotic ribosome.
The 70s prokaryotic ribosome is composed of one 50s and one 30s subunit. The difference in structure between eukaryotic and prokaryotic ribosomes allow antibiotics to target bacteria cells and limit side effects.
What do initiation factors (IFs) do in translation?
Initiation factors (IFs) assist with ribosomal subunit binding. The small subunit is recrutied first which then the large subunit is recruited already carrying the pre-charged/activated tRNA with bound methionine (start codon protein).
What is the P site?
The P site carries the bound tRNA with the protein that will later be transfered to the A site which later becomes the P site. The P site therefore holds the growing peptide chain.
What is the A site?
The A site holds the incoming charged tRNA and have their anti-codons read at the A site. This is where the protein on the P site is added by the enzyme peptidyl transferase and GTP.
What is the E site?
The E site is the transient location for uncharged (no amino acid bound) tRNA. This uncharged tRNA then dissociates from the ribosome at the E site (Exit Site).
What does a release factor (RF) do?
A release factor (RF) binds to the stop codon and ends translation of the mRNA strand.
What are termination factors
Describe the post-translational processing/modifications with protein conformation (active enzyme structures)?
The first post-translational process is folding the protein into it’s conformational form. That means the primary sequence (1° structure) must be folded into it’s Secondary(2°) structure (alpha-helices and beta-sheets), and then into its tertiary(3°) folded structure. The folded subunits then combine via hydrogen bonding and colavent bonding between amino acid side (functional) groups to comprise the Quaternary (4°) structure.
What is a post-translational processing/modification that deals with cleaving?
A cleaving post-translational modification involves cleavage of a polypetide chain.
- Post-Translational Cleaving Modifications include (EX): cutting a peptide chain (inactive) into a smaller peptide chain called insulin (active).
What is prenylation?
Prenylation is post-translational process of addying a hydrophobic molecules (lipids) to a protein.
