Question

proteins are composed of long chains of amino acids.
mrna codon chart
a protein was analyzed in a lab, and the first three amino acids were determined to be: leucine-proline-alanine. which dna base sequence could have coded for these amino acids?
○ aau gcg cgc
○ cuc ccg gcc
○ gac ggg ccc
○ gag ggc cgg

Explanation:

Step1: Find mRNA codons for leucine

Identify mRNA codons that code for leucine: CUU, CUC, CUA, CUG, UUA, UUG.

Step2: Find mRNA codons for proline

Identify mRNA codons that code for proline: CCU, CCC, CCA, CCG.

Step3: Find mRNA codons for alanine

Identify mRNA codons that code for alanine: GCU, GCC, GCA, GCG.

Step4: Convert mRNA to DNA template

DNA template strand is complementary to mRNA (A↔T, U↔A, C↔G, G↔C). Match to options:

• For leucine (CUC) → DNA: GAG
• For proline (CCC) → DNA: GGG
• For alanine (GCC) → DNA: CGG

Combined DNA sequence: GAG GGG CCC

Step5: Match to given options

Check which option matches the derived DNA sequence.

Answer:

GAG GGG CCC