Transcript transcription-translation-core-1231389105373484 - REVISION-IB2

The tRNA molecule
• tRNA molecules do the
final translating
• At one end the have a
specific amino acid
attached by a tRNA
activating enzyme
These enzymes do the first
part of translating
• At the other end they have
an anticodon which is
complementary to the
mRNA codons
© 2007 Paul Billiet ODWS
© St Edward’s University: Dept Chemistry and Biochemistry
3rd position ↓
2nd position
1st
position
U
C
A
G
U
Phe
Ser
Tyr
Cys
U
Phe
Ser
Tyr
Cys
C
Leu
Ser
STOP
STOP
A
Leu
Ser
STOP
Trp
G
Leu
Pro
His
Arg
U
Leu
Pro
His
Arg
C
Leu
Pro
Gln
Arg
A
Leu
Pro
Gln
Arg
G
Ile
Thr
Asn
Ser
U
Ile
Thr
Asn
Ser
C
Ile
Thr
Lys
Arg
A
Met
Thr
Lys
Arg
G
Val
Ala
Asp
Gly
U
Val
Ala
Asp
Gly
C
Val
Ala
Glu
Gly
A
Val
Ala
Glu
Gly
G
C
A
G
© 2007 Paul Billiet
ODWS
Acidic
Basic
Uncharged Polar
Non-polar
http://learn.genetics.utah.edu/content/begin/dna/firefly/
Translation1
AUGGGAUACACUUUUUGA
Ribosome
© 2007 Paul Billiet ODWS
mRNA
Translation 2
met
amino acid
tRNA
UAC
anticodon
AUGGGAUACACUUUUUGA
© 2007 Paul Billiet ODWS
Translation 3
gly
met
CCU
UAC
AUGGGAUACACUUUUUGA
© 2007 Paul Billiet ODWS
Translation 4
peptide bond
met
gly
UAC CCU
AUGGGAUACACUUUUUGA
© 2007 Paul Billiet ODWS
Translation 5
tyr
met
gly
AUG
UAC
CCU
AUGGGAUACACUUUUUGA
© 2007 Paul Billiet ODWS
Translation 6
met
gly
tyr
CCU AUG
AUGGGAUACACUUUUUGA
© 2007 Paul Billiet ODWS
Translation 7
thr
met
gly
tyr
UGA
CCU
AUG
AUGGGAUACACUUUUUGA
© 2007 Paul Billiet ODWS
Translation 8
phe
polypeptide chain
met
gly
tyr
thr
AAA
AUG
UGA
AUGGGAUACACUUUUUGA
© 2007 Paul Billiet ODWS
Translation: the sequence
• The tRNA molecules with the correct anticodons are
lined up with their bases complementary to the
mRNA codons
• Two tRNA molecules at a time can fit on the
ribosome
• A peptide bond forms between their amino acids
• The first tRNA leaves the ribosome and mRNA move
along to accept a new tRNA
• The process of translation proceeds in the same
direction as replication and transcription (5’ to 3’)
© 2007 Paul Billiet ODWS