Lecture 5b - How can the DNA sequence of a gene code fro a specific protein? - translation Flashcards
1
Q
What is a codon?
A
- a triplet of bases
- each codes for 1 amino acid
2
Q
what is the amino acid that proteins always start with and what is the codon for this?
A
- methionine
- AUG
3
Q
What is the wobble base?
A
- when the third base doesn’t matter
4
Q
What do stop codons code for?
A
they don’t code for amino acids
5
Q
Describe tRNA
A
- different tRNA have different anticodons specific to evert codon
- amino acids are attached to the 3’ end by aminoacyl-tRNA-synthase
6
Q
What is aacinoacyl-tRNA-synthase?
A
an enzyme that connects an amino acid to its tRNA molecule
7
Q
Describe the structure of the ribosome
A
- 2 subunits made of RNA and protein
- core is made of rRNA
- protein stabilises the RNA structures
8
Q
Describe the function of the ribosome
A
- rRNA joins amino acids together via peptide transferase, making the peptide bond
9
Q
What is peptide transferase?
A
- An enzyme which adds amino acids together, forming peptide bonds, from their tRNA molecules
- made from the rRNA
10
Q
Describe the process of translation
A
- initiated by the small ribosome subunit
- moves along mRNA 5’ to 3’ until start codon is reached (methionine, AUG)
- methionine tRNA binds
- large RNA subunit binds
- reverse compliment tRNA to the mRNA the binds
- polypeptide bonds between amino acids form by peptide transferase
- moves along 1 codon at a time until stop codon is reached
- protein release factor binds
- dissociation of ribosome and translation stops
