Translation Flashcards
Who produced experiments to crack the genetic code?
Francis crick and Sydney Brenner
How many bases correspond to one amino acid?
4 types of base and 20 amino acids
3 nucleotides per amino acid so code is degenerate
Is the code overlapping
No because single base mutations only affect one amino acid
Describe Crick and Brenner’s experiment
Used bacteriophage T4 which infects E.Coli
Generated mutants in rII gene - “rapid lysis” phenotype of larger plaques
Generated mutants in RII gene of T4 using proflavin which causes frameshift mutations and intercalates between base pairs in DNA
Who deciphered the genetic code?
Nirenberg and Khorana
Describe amino acids:
More than one tRNA, some can tolerate a mismatch at the third codon position, stop codons do not code for amino acids
Single letter for amino acids allows protein sequences to be analysed digitally
Which types of RNA participate in translation
mRNAS, rRNAs and tRNAs
What do RNA do in translation?
mRNA carries the genetic info, tRNA deciphers the codons of mRNA and rRNA makes up the ribosome
Describe tRNA
Specific enzymes couple tRNAs to the correct amino acid, the anti-codon in the charged tRNA pairs with the codon in mRNA delivering its amino acid in the correct sequence
Describe rRNA
rRNA associates with a set of proteins to form the translational machinery, a ribosome is a large complex of 4 RNAs and more than 80 proteins
How is mRNA synthesised
5’ to 3’
Describe ribosome
Ribozyme - protein and rRNA which is responsible for catalysis of peptide bond formation
