11. Figure 17.5
Second mRNA base
FirstmRNAbase(5′endofcodon)
ThirdmRNAbase(3′endofcodon)
UUU
UUC
UUA
CUU
CUC
CUA
CUG
Phe
Leu
Leu
Ile
UCU
UCC
UCA
UCG
Ser
CCU
CCC
CCA
CCG
UAU
UAC
Tyr
Pro
Thr
UAA Stop
UAG Stop
UGA Stop
UGU
UGC
Cys
UGG Trp
GC
U
U
C
A
U
U
C
C
C
A
U
A
A
A
G
G
His
Gln
Asn
Lys
Asp
CAU CGU
CAC
CAA
CAG
CGC
CGA
CGG
G
AUU
AUC
AUA
ACU
ACC
ACA
AAU
AAC
AAA
AGU
AGC
AGA
Arg
Ser
Arg
Gly
ACGAUG AAG AGG
GUU
GUC
GUA
GUG
GCU
GCC
GCA
GCG
GAU
GAC
GAA
GAG
Val Ala
GGU
GGC
GGA
GGG
Glu
Gly
G
U
C
A
Met or
start
UUG
G
20. Figure 17.8
Transcription initiation
complex forms
3
DNA
Promoter
Nontemplate strand
5′
3′
5′
3′
5′
3′
Transcription
factors
RNA polymerase II
Transcription factors
5′
3′
5′
3′
5′
3′
RNA transcript
Transcription initiation complex
5′
3′
TATA box
T
T T T T T
A AA AA
A A
T
Several transcription
factors bind to DNA
2
A eukaryotic promoter1
Start point Template strand
22. Nontemplate
strand of DNA
RNA nucleotides
RNA
polymerase
Template
strand of DNA
3′
3′5′
5′
5′
3′
Newly made
RNA
Direction of transcription
A
A A A
A
A
A
T
T
T
T
TTT G
G
G
C
C C
C
C
G
C CC A A
A
U
U
U
end
Figure 17.9
43. Aminoacyl-tRNA
synthetase (enzyme)
Amino acid
P P P Adenosine
ATP
P
P
P
P
Pi
i
i
Adenosine
tRNA
AdenosineP
tRNA
AMP
Computer model
Amino
acid
Aminoacyl-tRNA
synthetase
Aminoacyl tRNA
(“charged tRNA”)
Figure 17.16-4
45. tRNA
molecules
Growing
polypeptide Exit tunnel
E P
A
Large
subunit
Small
subunit
mRNA
5′
3′
(a) Computer model of functioning ribosome
Exit tunnel Amino end
A site (Aminoacyl-
tRNA binding site)
Small
subunit
Large
subunit
E P A
mRNA
E
P site (Peptidyl-tRNA
binding site)
mRNA
binding site
(b) Schematic model showing binding sites
E site
(Exit site)
(c) Schematic model with mRNA and tRNA
5′ Codons
3′
tRNA
Growing polypeptide
Next amino
acid to be
added to
polypeptide
chain
Figure 17.17
53. Figure 17.20-3
Release
factor
Stop codon
(UAG, UAA, or UGA)
3′
5′
3′
5′
Free
polypeptide
2 GTP
5′
3′
2 GDP + 2 iP
When a ribosome reaches a stop
codon on mRNA, the A site of the
ribosome accepts a protein called
a release factor instead of tRNA.
The release factor hydrolyzes the
bond between the tRNA in the
P site and the last amino acid of the
polypeptide chain. The polypeptide
is thus freed from the ribosome.
The two ribosomal subunits
and the other components
of the assembly dissociate.
62. Figure 17.23
Wild-type hemoglobin
Wild-type hemoglobin DNA
3′
3′
3′5′
5′ 3′
3′5′
5′
5′5′3′
mRNA
A AG
C T T
A AG
mRNA
Normal hemoglobin
Glu
Sickle-cell hemoglobin
Val
A
A
AUG
G
T
T
Sickle-cell hemoglobin
Mutant hemoglobin DNA
C
66. Wild type
DNA template strand
mRNA5′
5′
3′
Protein
Amino end
A instead of G
(a) Nucleotide-pair substitution
3′
3′
5′
Met Lys Phe Gly Stop
Carboxyl end
T T T T T
TTTTTA A A A A
AAAACC
C
C
A
A A A A A
G G G G
GC C
G GGU U U U UG
(b) Nucleotide-pair insertion or deletion
Extra A
3′
5′
5′
3′
Extra U
5′ 3′
T T T T
T T T T
A
A A A
A
AT G G G G
GAAA
AC
CCCC A
T3′5′
5′ 3′
5′T T T T TAAAACCA AC C
TTTTTA A A A ATG G G G
U instead of C
Stop
UA A A A AG GGU U U U UG
MetLys Phe Gly
Silent (no effect on amino acid sequence)
T instead of C
T T T T TAAAACCA GT C
T A T T TAAAACCA GC C
A instead of G
CA A A A AG AGU U U U UG UA A A AG GGU U U G AC
AA U U A AU UGU G G C UA
GA U A U AA UGU G U U CG
Met Lys Phe Ser
Stop
Stop Met Lys
missing
missing
Frameshift causing immediate nonsense
(1 nucleotide-pair insertion)
Frameshift causing extensive missense
(1 nucleotide-pair deletion)
missing
T T T T TTCAACCA AC G
AGTTTA A A A ATG G G C
Leu Ala
Missense
A instead of T
TTTTTA A A A ACG G A G
A
CA U A A AG GGU U U U UG
TTTTTA T A A ACG G G G
Met
Nonsense
Stop
U instead of A
3′
5′
3′5′
5′
3′
3′
5′
5′
3′
3′5′ 3′
Met Phe Gly
No frameshift, but one amino acid missing
(3 nucleotide-pair deletion)
missing
3′
5′
5′
3′
5′ 3′
U
T CA AA CA TTAC G
TA G T T T G G A ATC
T T C
A A G
Met
3′
T
A
Stop
3′
5′
5′
3′
5′ 3′
Figure 17.24