NH2CHRCOOH

1
NH2---CHR---COOH
2
(hydrophilic)
(positively charged)
(negatively charged)
(hydrophobic)
Fig. 6.19
3
Fig. 6.21
4
Fig. 6.22
5
Loss-of-function mutations (generally recessive
alleles)
Gain-of-function mutations (generally dominant
alleles)
Hypermorphic Mutations
6
Incomplete Dominance
Fig. 6.24
7
THE CAT SAW THE DOG GET THE RAT
THE CAT SAW THE DOG END
GET THE RAT END
THE CAT SAW THE DOG END GET THE RAT END
8
Fig. 7.3
9
Summary Genetic Code

• Triplet codons
• Three nonsense (stop) codons
• Degenerate code
• Nonoverlapping codons
• THE CAT SAW THE DOG
• Translation initiates at set point
• Establishes reading frame
• Genes coding sequence colinear with protein
• 5 gt 3 N-terminus gt C-terminus

10
Simplified Gene Structure
Coding Sequence
11
upstream
downstream
1
1
RNA Polymerase synthesizes 5 to 3
12
Transcription Can Proceed on Opposite Strands
5
3
5
3
3
5
5
3
13
Prokaryotic Promoter Consensus Sequences
14
(No Transcript)
15
Prokaryotic Transcription Promoter Binding
Initiation
Fig. 7.9
16
Elongation
Prokaryotic
Eukaryotic
Fig. 7.9
17
Prokaryotic Termination
Fig. 7.9
18
Prokaryote
Eukaryote
Major Differences
1. Prokaryotes lack a nucleus
2. Processing of eukaryotic primary transcripts
19
(No Transcript)
20
5 Cap
7-methyl guanosine
5 - 5
Fig. 7.10
21
3 Poly-adenylation
Fig. 7.10
22
Eukaryotic Gene Structure
transcription start site
Stop codon
terminator
ATG
promoter





Exon
Exon expressed region
Intron intervening region
poly(A) site
UTR-Untranslated region
Coding Sequence
23
Anatomy of Exon/Intron Junctions
1. Splice donor junction of upstream exon and
intron 2. Splice acceptor junction of downstream
exon and intron 3. Branch site
Fig. 7.12
24
Spliceosomes
25
Fig. 7.12
26
(No Transcript)
27
Fig. 7.13
28
(No Transcript)
29
Fig. 7.16
30
Fig. 7.17
31
Fig. 7.18
32
5 to 3 along mRNA Peptide chain growns N to C
terminus
Fig. 7.18
33
Fig. 7.18
34
Fig. 7.18
35
Initiation codon AUG Stop codons UAA,
UAG, UGA
5CAUGCUAUGUUAUGUUAGGGUAAUGUAG3
AUGUUAUGUUAG
AUGCUAUGUUAUGUUAGGGUAAUGUAG
AUGUUAGGGUAA
36
Mutations And Gene Expression

• Within Coding Sequence
• Silent mutations
• Missense mutations
• Nonsense mutations
• Frameshift mutations
• Outside Coding Sequence
• Promoters and Terminators
• Splice donors and acceptors
• Transcription and Translation Molecules