U2L12 Flashcards
Describe the physical and chemical properties of a tRNA (transfer RNA)
Consists of a single RNA strand that is 80 nucleotides long
Looks like a cloverleaf
Why do tRNA molecules fold into a three dimensional conformation
Because of hydrogen bonds
What joins a specific amino acid to a tRNA
An aminoacyl tRNA synthetase
What are ribosomes and how many are involved in translation?
Two ribosomal subunits (large and small) are made of proteins and ribosomal RNA
Ribosomes facilitate specific coupling of tRNA anticodons with mRNA codons
How many binding sites for tRNA
P site
A site
E site
What do proteins called initiation factors do?
Bring in the large subunit that completes the translation initiation complex
What happens when a ribosome reaches a stop codon
The release factor promotes hydrolysis and the two ribosomal subunits and other components dissociate
Does the start codon count as an amino acid?
Yes but stop codon does not count
What is an SRP
A signal recognition particle binds to the signal peptide and brings it and its ribosome to the ER
What is a polyribosome
Multiple ribosomes can translate a single mRNA which enables cells to make many polypeptides quickly
What are silent mutations
Mutations that have no effect on amino acid produced by codon - still codes for the same acid
What are nonsense mutations?
Change an amino acid into a stop codon leading to nonfunctional protein
What are the 2 frame shift mutations
Insertion and deletion
What is a gene
A region of DNA that can be expressed to produce a final functional product
