Lecture 6: Protein Synthesis Flashcards
What are the essential components for translation?
- Ribosomes
- mRNA and the genetic code
- tRNA complexed with appropriate amino acid
What are the three steps in protein synthesis?
- Polypepetide initiation
- Polypeptide chain elongation
- Termination of protein synthesis
Components of an amino acid?
- Carboxyl group
- Amino group
- R-Group
Where are ribosomes found?
- Cytoplasm
2. ER
Groups of three bases are called…
…codons.
For most amino acids, there is more than one codon. What is this called?
Degenerate.
Where would one find an anticodon?
tRNA
The amino acid on a tRNA attaches to what end?
The 3’ hydroxyl end.
What kinds of post-transcriptional modifications does tRNA undergo?
- Addition of CCA sequences on 3’ (OH-) terminal.
2. Modification of bases at specific positions to produce “unusual bases.”
Before an amino acid is incorporated into a protein chain, it is attached by its _____ to the ____ of an appropriate tRNA molecule.
Carboxyl end, 3’ OH
What are the two purposes of adding an amino acid to a tRNA?
- Covalently links AA to tRNA containing correct anticodon.
2. Attachment activates the amino acid.
Catalyzes covalent linkage of specific AA to corresponding specific tRNA.
aminoacyl-tRNA Synthetase(s).
There is one for every AA>
What is the wobble hypothesis?
The idea that more ‘relaxed’ bonding takes place between the 3’ base of the codon and the 5’ base of the anticodon.
This arrangement allows a single tRNA to recognize several codons.
_____ _____, not ribosomes, are the starting point for translation.
Ribosomal subunits.
eIF2
Binds with met-tRNA and GTP to form met-tRNA-GTP-eIF2 complex.
