Lecture 20 Flashcards
Amino acids have a 3 letter code and a..
1 letter code
What is translation?
The process of mRNA to a protein
How did Watson and Crick find out how many bases code for one amino acid? (Triplet codon hypothesis)
They knew there was 20 amino acids
- worked out that a triplet of bases would make a possible 64 AA (with some redundancy)
- triplet was the closest
What is a codon?
A ‘word’ (a triplet) it encodes one amino acid
How did they figure out which triplet codon encodes for which amino acids?
Experimentally
How many of the 64 codons specify an amino acid?
61
Do amino acids have more than 1 codon?
Most do
What are the codons that specify stop?
3 of them
- UAA, UAG, UGA
What does the stop codons do
Sits at the end of the mRNA and doesn’t code for any AA so the protein stops being made
What is the start codon?
AUG (also specifies methionine) always first codon
What would enable tRNA to act as the adaptor between mRNA and amino acids?
The tRNA must have nucleotides
What does tRNA look like?
- small RNA molecule
- single/short strand RNA
- 70-80 nucleotide length
- at least 1 tRNA for each AA
- has a region that can bind AA
- a region that interacts with mRNA
What is translation?
The synthesis of proteins by ribosomes using mRNA as a set of instructions
What is the function of a ribosome?
The machine that allows protein synthesis
What is the structure of a ribosome?
- large subunit
- small subunit
Only come together when making proteins
