H protein synthesis.ppt

H1 The ic code
H2 Protein synthesis(translation) in prokaryotes
H3 Translation in eukaryotes
H4 Protein targeting
H5 Protein glycosylation
H protein synthesis
Overview
Restriction enzyme digestion
Nomenclature
Gel electrophoresis
Restriction maps
Restriction fragment length polymorphisms(RFLP)
Restriction enzymes
The ic code is a triplet code
The ic code is degenerate
Universality of the ic code
Reading frames
Open reading frames
H1 The ic code
Triplet code
The nucleotide sequence of the mRNA is colinear with the amino acid sequence of the polypeptide in encodes. The relationship between them is called the ic code
5’---3’ N terminal-----C terminal
Triplet code
The three nucleotides in group called codons
43=64 codons
Initiation codon (AUG)
stop codon ( UAA, UAG,UGA)
Triplet code
The ic code is degenerate
64 codons, but only 20 amino acids, so that, a single amino acid is coded for by several different codons, that is, degenerate.
Synonyms:different codons specify the same amino acid.
Triplet code
Codon and anticodon: a triplet of bases in a specific tRNA molecule. each base is the codon base –pairs with plementary base in the anticodon.
Wobble base-pairing
Degeneracy of the ic code
Wobble rules