Fig. 17-17

3355U

UA

ACGMet

GTP GDPInitiator

tRNA

mRNA5 3

Start codon

mRNA binding siteSmallribosomalsubunit

5

P site

Translation initiation complex

3

E A

Met

Largeribosomalsubunit

Initiating translation

Fig. 17-18-4

Amino endof polypeptide

mRNA

5

3E

Psite

Asite

GTP

GDP

E

P A

E

P A

GDPGTP

Ribosome ready fornext aminoacyl tRNA

E

P A

Fig. 17-19-3

Releasefactor

3

5Stop codon(UAG, UAA, or UGA)

5

32

Freepolypeptide

2 GDP

GTP

5

3

Terminating translation

Translation animation

How is this model different than what is in your textbook?

How are aminoacyl-tRNAs brought to the ribosome?

How are hydrogen bonds represented?

How is the expenditure of energy (GTP) represented?

What is “peptidyl synthetase”?

Fig. 17-3a-2

(a) Bacterial cell

TRANSCRIPTIONDNA

mRNA

TRANSLATIONRibosome

Polypeptide

Fig. 17-7a-4Promoter Transcription unit

DNAStart pointRNA polymerase

553

3

Initiation

33

1

RNAtranscript

5 5

UnwoundDNA

Template strandof DNA

2 Elongation

RewoundDNA

5

5 5 3 3 3

RNAtranscript

3 Termination

5

5 5 33

3Completed RNA transcript

Fig. 17-24

RNA polymerase

DNA

Polyribosome

mRNA

0.25 µmDirection oftranscription

DNA

RNApolymerase

Polyribosome

Polypeptide(amino end)

Ribosome

mRNA (5 end)

In bacteria:Translation can happen while transcription is still ocurring

Fig. 18-3a

Polypeptide subunits that make upenzymes for tryptophan synthesis

mRNA 5

Promoter

trp operon

Genes of operon

Stop codonStart codon

trpAtrpE trpD trpC trpB

ABCDE

In bacteria: Many genes are organized in operons

Operon = group of genes sharing one promoter, expressed as 1 mRNAs containing multiple ORFs

Fig. 17-3b-3

(b) Eukaryotic cell

TRANSCRIPTION

Nuclearenvelope

DNA

Pre-mRNARNA PROCESSING

mRNA

TRANSLATION Ribosome

Polypeptide

Fig. 17-8A eukaryotic promoterincludes a TATA box

3

1

2

3

Promoter

TATA box Start point

Template

TemplateDNA strand

535

Transcriptionfactors

Several transcription factors mustbind to the DNA before RNApolymerase II can do so.

5533

Additional transcription factors bind tothe DNA along with RNA polymerase II,forming the transcription initiation complex.

RNA polymerase IITranscription factors

55 53

3

RNA transcript

Transcription initiation complex

Fig. 17-9

Protein-coding segment Polyadenylation signal3

3 UTR5 UTR

5

5 Cap Start codon Stop codon Poly-A tail

G P PP AAUAAA AAA AAA…

A eukaryotic mRNA

Fig. 17-10

Pre-mRNA

mRNA

Codingsegment

Introns cut out andexons spliced together

5 Cap

Exon Intron5

1 30 31 104

Exon Intron

105

Exon

146

3Poly-A tail

Poly-A tail5 Cap

5 UTR 3 UTR1 146

Many eukaryotic mRNAs are spliced

Fig. 17-11-1RNA transcript (pre-mRNA)

Exon 1 Exon 2Intron

ProteinsnRNA

snRNPs

Otherproteins

5

Fig. 17-11-2RNA transcript (pre-mRNA)

Exon 1 Exon 2Intron

ProteinsnRNA

snRNPs

Otherproteins

5

5

Spliceosome

Fig. 17-11-3RNA transcript (pre-mRNA)

Exon 1 Exon 2Intron

ProteinsnRNA

snRNPs

Otherproteins

5

5

Spliceosome

Spliceosomecomponents

Cut-outintronmRNA

Exon 1 Exon 25

Fig. 17-12

GeneDNA

Exon 1 Exon 2 Exon 3Intron Intron

Transcription

RNA processing

Translation

Domain 2

Domain 3

Domain 1

Polypeptide