Parts is parts….AMINO ACIDbuilding block of proteins

contain an amino or NH2 group and a carboxyl (acid) or COOH group

PEPTIDE BONDcovalent bond link amino acids’ amino group to carboxyl (acid) group

PROTEINS long chains of amino acids held together by peptide bonds

Amino Acids

Glu = glutamic acidCys = cysteineTrp = tryptophanArg = arginineGly = glycine

His = histidineGln = glutamineAsn = asparagineLys = lysineAsp = aspartic acid

Ser = serinePro = prolineThr = threonineAla = alanineTyr = tyrosine

Phe = phenylalanineLeu = leucineIle = isoleucineMet = methionineVal = valine

GENE sequence of bases along one strand of DNA codes for messenger RNA

mRNA messenger RNAcauses protein synthesis

CODONA sequence of three nucleotides in messenger RNA that codes for a single amino acid

How does the cell know which

amino acid???

U C A G  

U

UUU = PheUUC = PheUUA = LeuUUG = Leu

UCU = SerUCC = SerUCA = SerUCG = Ser

UAU = TyrUAC = TyrUAA = StopUAG = Stop

UGU = CysUGC = CysUGA = StopUGG = Trp

UCAG

C

CUU = LeuCUC = LeuCUA = LeuCUG = Leu

CCU = ProCCC = ProCCA = ProCCG = Pro

CAU = HisCAC = HisCAA = GlnCAG = Gln

CGU = ArgCGC = ArgCGA = ArgCGG = Arg

UCAG

A

AUU = IleAUC = IleAUA = IleAUG = Met

ACU = ThrACC = ThrACA = ThrACG = Thr

AAU = AsnAAC = AsnAAA = LysAAG = Lys

AGU = SerAGC = SerAGA = ArgAGG = Arg

UCAG

G

GUU = ValCUC = ValGUA = ValGUG = Val

GCU = AlaGCC = AlaGCA = AlaGCG = Ala

GAU = AspGAC = AspGAA = GluGAG = Glu

GGU = GlyGCG = GlyGGA = GlyGGG = Gly

UCAG

The Genetic Code - Codons

Amino Acids

Glu = glutamic acidCys = cysteineTrp = tryptophanArg = arginineGly = glycine

His = histidineGln = glutamineAsn = asparagineLys = lysineAsp = aspartic acid

Ser = serinePro = prolineThr = threonineAla = alanineTyr = tyrosine

Phe = phenylalanineLeu = leucineIle = isoleucineMet = methionineVal = valine

RNA vs DNA RNA stands for “ribo” nucleic

acid sugar is ribose instead of

deoxyribose has a backbone like DNA and

it has 4 nucleotides thymine is replaced by

Uracil RNA only has one thread

Introduction

Protein Synthesis There are two steps from

DNA to proteinsTranscriptionTranslation

RNA polymerase recognizes the start point of a gene and begins to ‘unzip’ the DNA

nucleotide pattern from a gene on a DNA strand is transferred to an RNA strand (mRna)

Transcription

Translation Once at the ribosome, the mRNA

attaches. The ribosome coordinates the assembly of

the protein. Each amino acid is attached one by one

as the ribosome reads the next piece of mRNA (watch)

Every three nucleic acids correspond to one amino acid. Each such triple is called a codon.

U C A G  

U

UUU = PheUUC = PheUUA = LeuUUG = Leu

UCU = SerUCC = SerUCA = SerUCG = Ser

UAU = TyrUAC = TyrUAA = StopUAG = Stop

UGU = CysUGC = CysUGA = StopUGG = Trp

UCAG

C

CUU = LeuCUC = LeuCUA = LeuCUG = Leu

CCU = ProCCC = ProCCA = ProCCG = Pro

CAU = HisCAC = HisCAA = GlnCAG = Gln

CGU = ArgCGC = ArgCGA = ArgCGG = Arg

UCAG

A

AUU = IleAUC = IleAUA = IleAUG = Met

ACU = ThrACC = ThrACA = ThrACG = Thr

AAU = AsnAAC = AsnAAA = LysAAG = Lys

AGU = SerAGC = SerAGA = ArgAGG = Arg

UCAG

G

GUU = ValCUC = ValGUA = ValGUG = Val

GCU = AlaGCC = AlaGCA = AlaGCG = Ala

GAU = AspGAC = AspGAA = GluGAG = Glu

GGU = GlyGCG = GlyGGA = GlyGGG = Gly

UCAG

The Genetic Code - Codons

Introduction

Protein SynthesisMr.SchoenbrunSchool of the Arts