Question

use the codon chart to match the amino acid that corresponds to each codon found in mrna. remember that you must change the mrna into trna before selecting the codon. 40 points
met or start val lys ser ala gly leu
ccc
cag
gaa
uuu
agu
uac
cgu
cca

Explanation:

Step1: Match CCC to amino acid

Locate CCC in the codon chart: it corresponds to Proline (not listed, but we use given options? No, wait, correction: Wait, no, the given options are the ones to pick from? Wait no, recheck: Wait, the codon chart: CCC is Proline, but the options provided are Met/Start, Val, Lys, Ser, Ala, Gly, Leu. Wait no, wait the instruction says "change mRNA to tRNA before selecting the codon"? Wait no, correction: tRNA is complementary to mRNA, but to find the amino acid, we use the mRNA codon directly in the chart. Wait, no, the instruction says "change the mRNA into tRNA before selecting the codon"—wait, no, that's a misstatement? Wait no: tRNA anticodon is complementary to mRNA codon, so the codon we look up is the mRNA codon. Wait, let's go one by one:

1. CCC (mRNA codon): In the chart, first base C, second C, third C → Proline. But Proline is not in the options? Wait no, wait the options are Met or Start, Val, Lys, Ser, Ala, Gly, Leu. Wait, no, wait I misread: Wait the chart: CCC is under C (first base), second base C, third base C: Proline (Pro). But that's not an option. Wait no, wait the question says "match the amino acid that corresponds to each codon found in mRNA. Remember that you must change the mRNA into tRNA before selecting the codon." Oh! Wait, tRNA anticodon is complementary: mRNA CCC → tRNA GGG. Then we use the tRNA anticodon as a codon? No, no, the codon chart is for mRNA. Wait, no, the instruction might mean that tRNA anticodon pairs with mRNA codon, so the amino acid is determined by the mRNA codon. Wait, no, let's recheck the options: Wait the options given are the ones to circle, so maybe I misread the chart. Wait no, let's go step by step for each codon:

Step1: CCC (mRNA) to amino acid

Locate CCC in chart: C (1st), C (2nd), C (3rd) → Proline (not in options? No, wait no, the options are Met/Start, Val, Lys, Ser, Ala, Gly, Leu. Wait, no, wait the question's options must have a typo? No, wait no, I misread: Wait the instruction says "change mRNA to tRNA"—so mRNA CCC → tRNA GGG. Then GGG is Glycine (Gly). Oh! That's what the instruction means: use the tRNA sequence as the codon to look up. That's the key.

Step1: CCC → tRNA GGG

mRNA CCC → tRNA anticodon is complementary: C ↔ G, so tRNA = GGG. Look up GGG in chart: G (1st), G (2nd), G (3rd) → Glycine (Gly)

Step2: CAG → tRNA GUC

mRNA CAG → tRNA is GUC (C↔G, A↔U, G↔C). Look up GUC: G (1st), U (2nd), C (3rd) → Valine (Val)

Step3: GAA → tRNA CUU

mRNA GAA → tRNA CUU (G↔C, A↔U, A↔U). Look up CUU: C (1st), U (2nd), U (3rd) → Leucine (Leu)

Step4: UUU → tRNA AAA

mRNA UUU → tRNA AAA (U↔A, U↔A, U↔A). Look up AAA: A (1st), A (2nd), A (3rd) → Lysine (Lys)

Step5: AGU → tRNA UCA

mRNA AGU → tRNA UCA (A↔U, G↔C, U↔A). Look up UCA: U (1st), C (2nd), A (3rd) → Serine (Ser)

Step6: UAC → tRNA AUG

mRNA UAC → tRNA AUG (U↔A, A↔U, C↔G). Look up AUG: A (1st), U (2nd), G (3rd) → Methionine (Met or Start)

Step7: CGU → tRNA GCA

mRNA CGU → tRNA GCA (C↔G, G↔C, U↔A). Look up GCA: G (1st), C (2nd), A (3rd) → Alanine (Ala)

Step8: CCA → tRNA GGU

mRNA CCA → tRNA GGU (C↔G, C↔G, A↔U). Look up GGU: G (1st), G (2nd), U (3rd) → Glycine (Gly)

Answer:

• CCC: Gly
• CAG: Val
• GAA: Leu
• UUU: Lys
• AGU: Ser
• UAC: Met or Start
• CGU: Ala
• CCA: Gly

(To match the format, the circles would be filled as follows:
CCC → circle under Gly
CAG → circle under Val
GAA → circle under Leu
UUU → circle under Lys
AGU → circle under Ser
UAC → circle under Met or Start
CGU → circle under Ala
CCA → circle under Gly)