Figure 14.1

Figure 14.4a-2

mRNA

DNATRANSCRIPTION

TRANSLATION

Polypeptide

Ribosome

(a) Bacterial cell

Figure 14.4b-3

Nuclearenvelope

Pre-mRNA

mRNA

DNA

RNA PROCESSING

TRANSCRIPTION

TRANSLATION

Polypeptide

Ribosome

(b) Eukaryotic cell

Figure 14.5

DNAtemplatestrand

Protein

mRNA

3

Trp

TRANSCRIPTION

TRANSLATION

Amino acid

Codon

5

35

3

5

Phe Gly Ser

GU G U UU G G UC C A

CA C A AA C C AG G T

GT G T TT G G TC C A

Figure 14.6

UUU

Second mRNA base

UUC

UUA

UUG

UCU

UCC

UCA

UCG

UAU

UAC

UAA

UAG

UGU

UGC

UGA

UGG

CUU

CUC

CUA

CUG

CCU

CCC

CCA

CCG

CAU

CAC

CAA

CAG

CGU

CGC

CGA

CGG

AUU

AUC

AUA

AUG

ACU

ACC

ACA

ACG

AAU

AAC

AAA

AAG

AGU

AGC

AGA

AGG

GUU

GUC

GUA

GUG

GCU

GCC

GCA

GCG

GAU

GAC

GAA

GAG

GGU

GGC

GGA

GGG

Fir

st m

RN

A b

ase

(5

en

d o

f co

do

n)

U

C

A

G

U

C

A

G

U

C

A

G

U

C

A

G

U

C

A

G

U C A G

Phe

Leu

Ser

Tyr Cys

Trp

Met orstart

Stop

Stop Stop

Arg

Gln

His

ProLeu

Val Ala

Asp

Glu

Gly

IIeThr

Lys

Asn

Arg

Ser

Th

ird

mR

NA

bas

e (

3 e

nd

of

cod

on

)

Figure 14.7

(a) Tobacco plant expressinga firefly gene

(b) Pig expressing a jellyfishgene

Figure 14.8-3Transcription unit

RNA polymerase

Promoter

Template strand of DNA

Start point

Termination

Completed RNA transcript

RNA transcript

UnwoundDNA

RewoundDNA

RNA transcript

Direction oftranscription(“downstream”)

Initiation

Elongation

35

35

35 3

5

35

35

35

35

35

35

3

2

1

Figure 14.10

Nontemplate strand of DNA

Direction of transcription

RNA polymerase

3

53

5

RNA nucleotides

Template strand of DNA

Newly made RNA

3 end

5

UC

U

G

A

A

A

A

AA

A

AA

A

T T T

TT

T

T

CC

C

CCC C

G

GG

U

Figure 14.12

Introns cut out andexons spliced together

31–104

5 Cap

5 UTR 3 UTR

Poly-A tail

Codingsegment

1–146

AAUAAA

105– 146

5 Cap Poly-A tail

1–30

mRNA

Pre-mRNA

Intron Intron

Figure 14.UN04

DNA

mRNA

Ribosome

Polypeptide

TRANSLATION

TRANSCRIPTION

Figure 14.14

5

tRNA

Polypeptide

Ribosome

Anticodon

mRNA

Codons 3

tRNA withamino acidattached

Amino acids

Gly

Trp

Phe

A A A

A C C

CC

G

U U U G G CU G G

Animation: Translation Introduction

Figure 14.19-3Amino endof polypeptide

mRNARibosome ready fornext aminoacyl tRNA P

site

P i

5

3E

GTP

Asite

GDP

Peptide bondformation

Codon recognition

Translocation

E

P A

E

P A

P i

GTP

GDP

E

P A

3

2

1

Figure 14.22a

Incomingribosomalsubunits

(a) Several ribosomes simultaneously translating onemRNA molecule

Start of mRNA(5 end)

End of mRNA(3 end)

Growingpolypeptides

Completedpolypeptide

Polyribosome

Figure 14.23

RNA polymerase

mRNA

0.25 m

DNA

Polyribosome

RNA polymerase DNA

Polyribosome

Direction oftranscription

Ribosome

mRNA (5 end)

Polypeptide(amino end)

Figure 14.26

mRNA

DNA template strand

StopProtein Phe GlyMet Lys

A G3 T CC 5T T T TA A A AC C

5 3TA A A A AT T T TG G G G C

U5 3G CA U U G GGA A A AU U

Wild type

Phe GlyMet Lys

A A3 T CC 5T T T TA A A AC C

5 3TA A A A AT T T TG G G G T

U5 3G UA U U G GGA A A AU U

Phe SerMet Lys

A G3 T CC 5T T T TA A A AC T

5 3TA A A A AT T T TG G A G C

U5 3G CA U U A GGA A A AU U

Met

A C3 T CT 5A T A TC A A GC A

5 3TA T A T AG T T CG A T G G

U5 3G GA G U U GAU A U AU U

Leu AlaMet Lys

A A3 T GC 5T T T

A

A A C TC C

5 3TA A A AGT T AG G G C T

U5 3G UA U G G GGA A A

U

U A

GlyMet Phe

A T3 T TA 5A A

T T

C C G

C

C A

5 3TA T T

A

A

G G C

T

G T T A A

U5 3G AA G C U AUU U

A G

G

A

Met

A G3 T CC 5A T T TA A A AC C

5 3TA T A A AT T T TG G G G C

U5 3G UA U U G GGU A A AU U

Stop Stop

Stop

Stop

Stop

A instead of G

Silent (no effect on amino acid sequence)

(a) Nucleotide-pair substitution

U instead of C

T instead of C

Missense

A instead of G

A instead of T

Nonsense

U instead of A

Extra A

Frameshift causing immediate nonsense(1 nucleotide-pair insertion)

(b) Nucleotide-pair insertion or deletion

Extra U

Frameshift causing extensive missense(1 nucleotide-pair deletion)

missing

missing

missing

missing

No frameshift, but one amino acid missing(3 nucleotide-pair deletion)

Animation: Protein Synthesis

15Regulation of

Gene Expression

Figure 15.2

Regulationof geneexpression

Precursor

trpE gene

(a) Regulation of enzyme activity

Feedbackinhibition

Enzyme 1

Enzyme 2

Enzyme 3

Tryptophan

(b) Regulation of enzyme production

trpD gene

trpC gene

trpB gene

trpA gene

Operon: Genes that code for similar things are grouped together with a regulatory gene that controls their transcription

Figure 15.3a

(a) Tryptophan absent, repressor inactive, operon on

Protein

Inactiverepressor

mRNA

5

3

E D C B A

Regulatorygene

RNApolymerase

Genes that code for enzymes that make tryptophan

Operator

mRNA 5

trpE trpD trpC trpB trpAtrpR

Repressible operon: Tryptophan

Figure 15.3b

DNA

mRNA

Protein Activerepressor

No RNAmade

Tryptophan(corepressor)

(b) Tryptophan present, repressor active, operon off

What happens when tryptophan is present?Don‘t need to make tryptophan-building enzymes!

Figure 15.4b

IacZ IacY IacAIacI

lac operon

Permease Transacetylase-Galactosidase

mRNA

Protein

RNA polymerase

mRNA 53

5

Inactiverepressor

Allolactose(inducer)

(b) Lactose present, repressor inactive, operon on

Inducible operon: Lactose

Figure 15.4a

DNA

PromoterOperator

Regulatorygene

NoRNAmade

IacZlacI

mRNA RNApolymerase

3

5

ActiverepressorProtein

(a) Lactose absent, repressor active, operon off

Figure 15.10-3

DNA

EnhancerDistal controlelement

Activators PromoterGene

TATA box

DNA-bendingprotein

Group of mediator proteins

General transcriptionfactors

RNApolymerase II

RNApolymerase II

RNA synthesisTranscriptioninitiation complex

Figure 15.11Albumin gene

Crystallin gene

Promoter

Promoter

(b) LENS CELL NUCLEUS

Availableactivators

Albumin genenot expressed

Crystallin geneexpressed

Crystallin genenot expressed

Albumin geneexpressed

Availableactivators

(a) LIVER CELL NUCLEUS

Controlelements

Enhancer

Enhancer