Question

translation:
level 1: use the codon chart to identify
the amino acid that goes with the
following mrna codons:
uuu= _______
cug= _______
aug=_______
uga=_______
(write the amino acid as the three letter
abbreviation...ex: met, val, leu)
(the codon chart is presented with first letter (u, c, a, g) on the left, second letter (u, c, a, g) on the top, and third letter (u, c, a, g) on the right. the codon - amino acid mappings are as follows:
for first letter u:

• second letter u: uuu, uuc (phe); uua, uug (leu)
• second letter c: ucu, ucc, uca, ucg (ser)
• second letter a: uau, uac (tyr); uaa, uag (stop)
• second letter g: ugu, ugc (cys); uga (stop); ugg (trp)

for first letter c:

• second letter u: cuu, cuc, cua, cug (leu)
• second letter c: ccu, ccc, cca, ccg (pro)
• second letter a: cau, cac (his); caa, cag (gln)
• second letter g: cgu, cgc, cga, cgg (arg)

for first letter a:

• second letter u: auu, auc, aua (ile); aug (met)
• second letter c: acu, acc, aca, acg (thr)
• second letter a: aau, aac (asn); aaa, aag (lys)
• second letter g: agu, agc (ser); aga, agg (arg)

for first letter g:

• second letter u: guu, guc, gua, gug (val)
• second letter c: gcu, gcc, gca, gcg (ala)
• second letter a: gau, gac (asp); gaa, gag (glu)
• second letter g: ggu, ggc, gga, ggg (gly))

Explanation:

Step1: Identify UUU codon

Look at the codon chart. For UUU, the first letter is U, second is U, third is U. In the chart, UUU is grouped with UUC under Phe. So UUU corresponds to Phe.

Step2: Identify CUG codon

First letter C, second U, third G? Wait, no: CUG has first letter C, second U, third G? Wait, the chart: first letter C, second U? Wait, no, CUG: first letter C, second U? Wait, no, the first letter is C, second letter U? Wait, no, the codon CUG: first letter C, second letter U? Wait, no, looking at the chart, under first letter C, the codons with second letter U? Wait, no, the chart for first letter C: the rows are first letter U, C, A, G. For first letter C, the codons are CUU, CUC, CUA, CUG (second letter U? Wait, no, the second letter columns are U, C, A, G. Wait, CUG: first letter C, second letter U? No, CUG: first letter C, second letter U? Wait, no, CUG: C (first), U (second), G (third)? Wait, no, the chart: first letter C, second letter U? Wait, no, the first letter C row: the second letter columns are U, C, A, G? Wait, no, the columns are second letter U, C, A, G. So for CUG: first letter C (row), second letter U? No, CUG: C (first), U (second), G (third)? Wait, no, the codon CUG: C (first), U (second), G (third)? Wait, looking at the chart, under first letter C, the codons with second letter U? Wait, no, the first letter C row: the codons are CUU, CUC, CUA, CUG (second letter U? Wait, no, the second letter for these is U? Wait, no, the second letter columns are U, C, A, G. So CUU: first C, second U, third U. CUC: first C, second U, third C. CUA: first C, second U, third A. CUG: first C, second U, third G. And they are grouped under Leu. So CUG is Leu.

Step3: Identify AUG codon

AUG: first letter A, second U, third G. Looking at the chart, first letter A, second U, third G: AUG is listed as Met.

Step4: Identify UGA codon

First letter U, second G, third A? Wait, UGA: first letter U, second G, third A? Wait, UGA: U (first), G (second), A (third)? Wait, the chart: first letter U, second letter G, third letter A? Wait, the U row: second letter G, third letter A: UGA is Stop.

Answer:

UUU = Phe
CUG = Leu
AUG = Met
UGA = Stop