1a. The template DNA strand, from which the mRNA is synthesized, is 5’ CAAACTACCCTGGGTTGCCAT 3’
(RNA synthesis proceeds in a 5’ à 3’ direction, so the template strand and the mRNA will be complementary to each other)
Â
b. The coding DNA strand, which is complementary to the template strand, is 5’ ATGGCAACCCAGGGTAGTTTG 3’
Â
c. The sequence of the mRNA is 5’ AUGGCAACCCAGGGUAGUUUG 3’
(the sequence of the mRNA is complementary to the template strand and identical to the coding strand with U substituted for T)
Â
d. The third codon is 5’ ACC 3’.  Therefore, the corresponding anti-codon is 5’ GGU 3’
Â
Â
2. Below is a table for the genetic code:
Â
Â
T
C
A
G
T
TTT Phe (F)
TTC "
TTA Leu (L)
TTG "
TCT Ser (S)
TCC "
TCA "
TCG "
TAT Tyr (Y)
TAC "
TAA Stop
TAG Stop
TGT Cys (C)
TGC "
TGA Stop
TGG Trp (W)
C
CTT Leu (L)
CTC "
CTA "
CTG "
CCT Pro (P)
CCC "
CCA "
CCG "
CAT His (H)
CAC "
CAA Gln (Q)
CAG "
CGT Arg (R)
CGC "
CGA "
CGG "
A
ATT Ile (I)
ATC "
ATA "
ATG Met (M)
ACT Thr (T)
ACC "
ACA "
ACG "
AAT Asn (N)
AAC "
AAA Lys (K)
AAG "
AGT Ser (S)
AGC "
AGA Arg (R)
AGG "
G
GTT Val (V)
GTC "
GTA "
GTG "
GCT Ala (A)
GCC "
GCA "
GCG "
GAT Asp (D)
GAC "
GAA Glu (E)
GAG "
GGT Gly (G)
GGC "
GGA "
GGG "
Â
a. The following codons can be mutated by one base to produce an amber codon:
CAG Â Â Gln
AAG Â Â Lys
GAG Â Â Glu
TCG Â Â Ser
TTG Â Â Leu
TGG Â Â Trp
TAA Â Â Stop
TAT Â Â Tyr
TAC Â Â Tyr
Â
b. From part a, CAG (Gln) and TGG (Trp) can become amber stop codons through EMS.
Â
c. From part b, both of the resulting amber codons could be suppressed by amber nonsense suppressors generated by EMS.
Â
Â
3a. The codon is the three nucleotide sequence in the mRNA that indicates which amino acid should be incorporated in the growing polypeptide chain. Â The anticodon is the complementary three nucleotide sequence in the appropriate tRNA.
Â
b. Template strand is the DNA strand off which the mRNA is synthesized. Â The coding, or non-template, strand is the DNA strand complementary to the template strand; it has the same sequence (except for T for U substitutions) as the mRNA.
Â
c. The Pribnow box is a sequence of six nucleotides (TATAAT) positioned at -10 that signals where transcription initiation should begin in prokaryotic DNA. Â The Shine-Delgarno sequence is a short, purine-rich region in the mRNA that is complementary to the rRNA within the 16S ribosomal subunit. Â The sequence signals which AUG acts as the translation start in mRNA.
Â
Â
4a. False, a wobble allows the anticodon in the tRNA to hybridize with different codons in mRNA.
Â
b. False, a frameshift mutation affects all the subsequent amino acids.
Â
c. False, only one codon (AUG) encodes for the start of protein synthesis; three codons signal the end of protein synthesis.
Â
d. False, the wobble is first base (5’ to 3’) in the anticodon.
Â
e. True, RNA can be used as a template for DNA synthesis in a process known as reverse transcription.
Â
f. True. Â For example, a single base substitution causing CAT to change to AAT would signal a termination.
Â
g. False, the Wobble Hypothesis explains how alternate base pairing can occur with the first nucleotide (going from 5' to 3') in the anticodon.
Â
Â
5a. Digestion of RNA with alkali will cleave the strand after each 3’ phosphate.  Therefore, the products remaining will consist of pppNp, Np, and N-OH
Â
b. If RNA was synthesized in the 3’ to 5’ direction (i.e. by adding ribonucleotides to the 5’ end), then the pppNp and Np fragments should be labeled with tritium.
Â
c. If RNA was synthesized in the 5’ to 3’ direction (i.e. by adding ribonucleotides to the 3’ end), then the Np and N-OH fragments should be labeled with tritium.
Â
d. Since the N-OH fragments were labeled with tritium, RNA synthesis must occur in a 5' to 3' direction.
Â
Â
6. In a missense mutation, the new nucleotide alters the codon so as to produce an altered amino acid in the protein product. Â With a nonsense mutation, the new nucleotide changes a codon that specified an amino acid to one of the stop codons (TAA, TAG, or TGA). Therefore, translation of the messenger RNA transcribed from this mutant gene will stop prematurely.
Â
Explanation:
:)