A partial DNA segment and an mRNA codon chart are shown.

Question

3', T, C, A, T, G, C, A ,T, G, 5'.
What amino acid sequence is encoded in the partial DNA segment?

Answer 1

To determine the amino acid sequence encoded by the given partial DNA segment, we need to follow these steps:

1. Transcription: Convert the DNA sequence to mRNA. The mRNA is synthesized using the DNA as a template, with adenine (A) replaced by uracil (U) in RNA. The DNA strand is read from the 3' to 5' direction to synthesize mRNA in the 5' to 3' direction.

   Given DNA strand:

   3' - T C A T G C A T G - 5'
   

   The complementary mRNA sequence would be:

   5' - A G U A C G U A C - 3'
   

2. Translation: Use the mRNA codon chart to translate the mRNA sequence into an amino acid sequence. The mRNA sequence is divided into codons (groups of three nucleotides).

   mRNA codons:

   • AGU
   • ACG
   • UAC

3. Codon to Amino Acid Translation:

   • AGU → Serine (Ser)
   • ACG → Threonine (Thr)
   • UAC → Tyrosine (Tyr)

Thus, the amino acid sequence encoded by the given DNA segment is:

Ser - Thr - Tyr.