mRNA leaves the nucleus through the pores to enter the cytoplasm ( Codon = 3 bases)
Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)
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Transcript of Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)
![Page 1: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/1.jpg)
Fig. 17-5Second mRNA base
Firs
t mRN
A ba
se (5
end
of c
odon
)
Third
mRN
A ba
se (3
end
of c
odon
)
![Page 2: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/2.jpg)
Polypeptide
Ribosome
Aminoacids
tRNA withamino acidattached
tRNA
Anticodon
Trp
Phe Gly
Codons 35
mRNA
the mechanism of translation
![Page 3: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/3.jpg)
Fig. 17-14
Amino acidattachment site
3
5
Hydrogenbonds
Anticodon
(a) Two-dimensional structure
Amino acidattachment site
5
3
Hydrogenbonds
3 5AnticodonAnticodon
(c) Symbol used in this book(b) Three-dimensional structure
![Page 4: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/4.jpg)
Amino acid Aminoacyl-tRNAsynthetase (enzyme)
ATP
AdenosineP P P
AdenosineP
PP i
PPi
i
tRNA
tRNA
Aminoacyl-tRNAsynthetase
Computer modelAMPAdenosineP
Aminoacyl-tRNA(“charged tRNA”)
Attaching amino acids to tRNAs:Amino-acyl tRNA synthases
-20 different synthases-Require ATP-Each must be specific to the right amino acid and tRNA(s)
![Page 5: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/5.jpg)
tRNAGLN
Aminoacyl-tRNA synthase(ATSGLN)
Adenylated Glutamine
![Page 6: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/6.jpg)
Fig. 17-16b
P site (Peptidyl-tRNAbinding site) A site (Aminoacyl-
tRNA binding site)E site(Exit site)
mRNAbinding site
Largesubunit
Smallsubunit
(b) Schematic model showing binding sites
Next amino acidto be added topolypeptide chain
Amino end Growing polypeptide
mRNAtRNA
E P A
E
Codons
(c) Schematic model with mRNA and tRNA
5
3
![Page 7: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/7.jpg)
The Ribosome
LSU
SSU
![Page 8: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/8.jpg)
Fig. 17-18-1
Amino endof polypeptide
mRNA
5
3E
Psite
Asite
![Page 9: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/9.jpg)
Fig. 17-18-2
Amino endof polypeptide
mRNA
5
3E
Psite
Asite
GTP
GDP
E
P A
![Page 10: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/10.jpg)
Fig. 17-18-3
Amino endof polypeptide
mRNA
5
3E
Psite
Asite
GTP
GDP
E
P A
E
P A
![Page 11: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/11.jpg)
Peptide bond formation- Transfer of growing chain from tRNA in P site to tRNA in A site
![Page 12: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/12.jpg)
Fig. 17-18-3
Amino endof polypeptide
mRNA
5
3E
Psite
Asite
GTP
GDP
E
P A
E
P A
![Page 13: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/13.jpg)
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
![Page 14: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/14.jpg)
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
![Page 15: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/15.jpg)
Fig. 17-19-1
Releasefactor
3
5Stop codon(UAG, UAA, or UGA)
Terminating translation
![Page 16: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/16.jpg)
Fig. 17-19-2
Releasefactor
3
5Stop codon(UAG, UAA, or UGA)
5
32
Freepolypeptide
2 GDP
GTP
Terminating translation
![Page 17: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/17.jpg)
Fig. 17-19-3
Releasefactor
3
5Stop codon(UAG, UAA, or UGA)
5
32
Freepolypeptide
2 GDP
GTP
5
3
Terminating translation
![Page 18: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/18.jpg)
Fig. 17-20
Growingpolypeptides
Completedpolypeptide
Incomingribosomalsubunits
Start ofmRNA(5 end)
PolyribosomeEnd ofmRNA(3 end)
(a)
Ribosomes
mRNA
(b) 0.1 µm
![Page 19: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/19.jpg)
Second mRNA base
Firs
t mRN
A ba
se (5
end
of c
odon
)
Third
mRN
A ba
se (3
end
of c
odon
)
The genetic code:-read in triplet codons
-once a start codon is specified, codons are read in order (5’ to 3) until a “stop” codon is read
-redundant
-unambiguous
-universal*
![Page 20: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/20.jpg)
DNA sequence
RNA sequence
Amino acid sequence
Protein structure and function
tRNAGLN
Aminoacyl-tRNA synthase(ATSGLN)
Adenylated Glutamine
![Page 21: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/21.jpg)
tRNAGLN
Aminoacyl-tRNA synthase(ATSGLN)
Adenylated Glutamine
Altered DNA sequence
Altered RNA sequence
Altered (?) Amino acid sequence
Altered (?) Protein structure and function
![Page 22: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/22.jpg)
Fig. 5-17Nonpolar
Glycine(Gly or G)
Alanine(Ala or A)
Valine(Val or V)
Leucine(Leu or L)
Isoleucine(Ile or I)
Methionine(Met or M)
Phenylalanine(Phe or F)
Trypotphan(Trp or W)
Proline(Pro or P)
Polar
Serine(Ser or S)
Threonine(Thr or T)
Cysteine(Cys or C)
Tyrosine(Tyr or Y)
Asparagine(Asn or N)
Glutamine(Gln or Q)
Electricallycharged
Acidic Basic
Aspartic acid(Asp or D)
Glutamic acid(Glu or E)
Lysine(Lys or K)
Arginine(Arg or R)
Histidine(His or H)
The 20 amino acids
![Page 23: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/23.jpg)
Fig. 17-23a
Wild type
3DNA templatestrand
3
355
5mRNA
Protein
Amino endStop
Carboxyl end
A instead of G
33
3
U instead of C
55
5
Stop
Silent (no effect on amino acid sequence)
![Page 24: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/24.jpg)
Fig. 17-23a
Wild type
3DNA templatestrand
3
355
5mRNA
Protein
Amino endStop
Carboxyl end
A instead of G
33
3
U instead of C
55
5
Stop
Silent (no effect on amino acid sequence)
![Page 25: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/25.jpg)
Fig. 17-23b
Wild type
DNA templatestrand
35
mRNA
Protein
5
Amino endStop
Carboxyl end
53
3
T instead of C
A instead of G
33
3
5
5
5
Stop
Missense
![Page 26: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/26.jpg)
Fig. 17-22
Wild-type hemoglobin DNA
mRNA
Mutant hemoglobin DNA
mRNA
33
3
3
3
3
55
5
55
5
C CT T TTG GA A AA
A A AGG U
Normal hemoglobin Sickle-cell hemoglobin
Glu Val
![Page 27: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/27.jpg)
Fig. 17-23cWild type
DNA templatestrand
35
mRNA
Protein
5
Amino endStop
Carboxyl end
53
3
A instead of T
U instead of A
33
3
5
5
5
Stop
Nonsense
![Page 28: Fig. 17-5 Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)](https://reader038.fdocuments.in/reader038/viewer/2022110211/56649efd5503460f94c11f0b/html5/thumbnails/28.jpg)
Fig. 17-23e
Wild type
DNA templatestrand
35
mRNA
Protein
5
Amino end
Stop
Carboxyl end
53
3
missing
missing
33
3
5
5
5
Frameshift causing extensive missense (1 base-pair deletion)