Question

which mrna codon and amino acid correspond to the dna sequence gcc? use complementary base pairing and this codon chart to answer the question. write the amino acid using its three - letter abbreviation. write stop for a stop codon. dna sequence gcc mrna codon amino acid

Explanation:

Step1: Transcribe DNA to mRNA

In transcription, DNA base pairs with mRNA: G→C, C→G, C→G. So DNA GCC → mRNA $\text{CGG}$? No, correction: DNA template strand pairs as follows: DNA G pairs with mRNA C, DNA C pairs with mRNA G, DNA C pairs with mRNA G. Wait, no: DNA coding strand (the given sequence) transcribes to mRNA with same code except T→U. Since DNA has G, C, C, mRNA will be $\text{CGG}$? No, reverse: Wait, DNA template is complementary to mRNA. If given DNA is the coding strand (non-template), mRNA matches it with T→U. But DNA has no T, so GCC (DNA) → mRNA $\text{GCC}$? No, no: Base pairing rules for transcription: DNA A→U, T→A, C→G, G→C. So DNA sequence GCC:

• G (DNA) → C (mRNA)
• C (DNA) → G (mRNA)
• C (DNA) → G (mRNA)

Wait, no, this is if the DNA is the template strand. If the DNA is the coding strand, mRNA is identical (replace T with U). But standard: when given a DNA sequence for codon, we use the template strand to make mRNA. Wait, no, let's correct:
Step1: Transcribe DNA to mRNA. DNA G pairs with C, C pairs with G, C pairs with G. So mRNA codon is $\text{CGG}$? No, wait the codon chart has GCC as alanine. Oh right! The coding strand of DNA is the same as mRNA (except T→U). So DNA GCC (coding strand) → mRNA GCC. Yes, that's correct, because the template strand would be CGG, which transcribes to GCC mRNA.

Step1: Transcribe DNA to mRNA

DNA (coding) GCC → mRNA $\text{GCC}$ (since G→G, C→C, C→C; no T to replace with U)

Step2: Match mRNA to amino acid

Use the codon chart: find first letter G, second letter C, third letter C. This corresponds to alanine (Ala).

Answer:

mRNA codon: GCC
amino acid: Ala