Download Name: Date: Transcription and Translation Worksheet – ANSWER

Name: _____________KEY______________
Date: ___________________
Transcription and Translation Worksheet – ANSWER KEY
Replicate what you’ve learned by translating your knowledge into good answers and
transcribing them onto this sheet. (Three. Three puns. Yes, I went there.)
1) Fill in the complementary bases for the blank DNA strand given below:
2) Complete the following tables by filling in the DNA sequence, mRNA codons, and tRNA
anticodons, as well as the amino acids expected in the final protein (using the mRNA
codons table handed out to you):
DNA
mRNA
tRNA
AA
TAC
AUG
UAC
Met
DNA
mRNA
tRNA
AA
DNA
mRNA
tRNA
AA
TAC
AUG
UAC
Met
CGC
GCG
CGC
Ala
TAC
AUG
UAC
Met
TCC
AGG
UCC
Arg
TGA
ACU
UGA
Thr
CAC
GUG
CAC
Val
TCG
AGC
UCG
Ser
CCC
GGG
CCC
Gly
GCC
CGG
GCC
Arg
ACC
UGG
ACC
Trp
CGT
GCA
CGU
Ala
GTC
CAG
GUC
Gln
CCC
GGG
CCC
Gly
ATG
UAC
AUG
Tyr
GAC
CUG
GAC
Leu
ATA
UAU
AUA
Tyr
GCT
CGA
GCU
Arg
AAT
UUA
AAU
Leu
ATG
UAC
AUG
Tyr
GGG
CCC
GGG
Pro
ACC
UGG
ACC
Trp
AAA
UUU
AAA
Phe
AAT
UUA
AAU
Leu
ACT
UGA
ACU
Stop
ATC
UAG
AUC
Stop
ATC
UAG
AUC
Stop
Name: _____________KEY______________
Date: ___________________
3) Create an mRNA strand based off of the given DNA template strand:
5’ – A U G A A G G A U A A A A G A A C A G U G G C G U G A – 5’
4) Using the mRNA codon chart, determine the amino acid sequence for the mRNA
sequence determined in question 2.
Met – Lys – Asp – Lys – Arg – Thr – Val – Ala - STOP
5) If a mutation occurred to the fourth base in the DNA template strand (thymine) and a
substitution occurred such that guanine replaced the thymine, would the final protein
be changed? If so, how?
The final protein WILL change. The second amino acid will be GLUTAMINE instead of
LYSINE.
6) If a substitution occurred to the 6th base in the DNA template strand, such that cytosine
was changed to thymine, would the final protein change? Why?
No. Initially, the DNA strand had the triplet TTC – this created the mRNA codon AAG. If
we change the template to TTT, the new codon would be AAA. Both AAG and AAA
code for lysine, so the final protein should still turn out the same (thanks to the
redundancy in the genetic code)!
7) Consider the following double-stranded DNA molecule:
5’ – ATGTGTAGTGCGAGTTGA – 3’
3’ – TACACATCACGCTCAACT – 5’
a) Which of these two strands will act as the template strand for transcription?
The 3’  5’ strand.
b) What would be the amino acid sequence coded for by the template strand of the
DNA molecule above?
Met – Cys – Ser – Ala – Ser – STOP
Name: _____________KEY______________
Date: ___________________
c) If the last base in the underlined sequence on the template strand was changed to
to a “C” (cytosine), how would the protein be changed?
This would cause the final serine to be changed to an arginine. The sequence in the
protein will now be:
Met – Cys – Ser – Ala – Arg - STOP
d) If the 4th base (reading from the left) in the DNA template strand was deleted
(removed) by radiation, how would the amino acid sequence in the final protein be
affected?
The whole sequence after the deletion will be affected because you’ll still be
reading three bases at a time, so the “reading frame” has shifted.
The new amino acid sequence will be:
Met – Val – Val – Arg – Val
There is no longer a proper stop codon, either. The new protein will barely
resemble the original.