Lecture 18 Objectives Flashcards
(24 cards)
What is translation?
Synthesis of proteins from mRNA
Where does translation occur?
Ribosomes
Where are ribosomes located?
In the cytosol or attached to rough ER
What are the 3 steps of translation?
Initiation, elongation, and termination
What is a codon?
A sequence of 3 mRNA nucleotides that does a unit of genetic code
What is a universal codon?
It has the same genetic code in all species with some minor deviations in mitochondria and a few single-celled organisms
What is a not ambiguous codon?
A codon that can only code for 1 amino acid
What is a degenerate codon?
More than one codon can code for the same amino acid
What is the wobble hypothesis?
The 3rd codon pairs loosely with the anticodon
What are the three sites on the large ribosomal subunit?
E-site, P-site, A-site
What co-translational modification occurs?
Acetylation - 1st amino acid is removed and replaced by acetyl group
Where does co-translational protein sorting occur?
ER
What is the targeting cell of the co-translational protein sorting?
N-terminus
What is a polysome?
Many ribosomes to translate one strand at a time
All proteins are translocated from the ER to what organelle?
Golgi apparatus
What types of post-translational modifications occur?
Lipidation, phosphorylation, proteolysis, ubiquitination, methylation
From the golgi, what 3 places can proteins be translocated?
Plasma membrane, lysosomes, ER
What are the targeting signals in the plasma membrane?
Carbohydrates and lipids added to protein
What are the targeting signals in lysosomes?
Carbohydrates and phosphate groups added to proteins
What are the targeting signals in the ER?
C-terminus
Where are proteins translocated?
Nucleus, mitochondria, or peroxisomes
What are the targeting signal in the nucleus?
Nuclear localization signal
What are the targeting signals in the mitochondria?
N-terminus
What are the targeting signals in the peroxisomes?
C-terminus or n-terminus
