The following is the nucleotide sequence of a strand of DNA

The following is the nucleotide sequence of a strand of DNA: TACGTCTCCAGCGGAGATCTTTTCCGGTCGCAACTGAGGTTGATC The strand is used as a template for an mRNA going from left to right. The mRNA encodes a small peptide. a) Which end of the DNA is the 3\' end and which is the 5\' end? b) What is the sequence of the complementary DNA strand? c) What is the sequence of the transcript? d) What is the amino acid sequence of the peptide?

Solution

a. 3\' end is at extreme left and 5\' at extremme right.

b. DNA chain: 3\' TAC GTC TCC AGC GGA GAT CTT TTC CGG TCG CAA CTG AGG TTG ATC 5\'

Complementary chain: 5\' ATG CAG AGG TCG CCT CTA GAA AAG GCC AGC GTT GAC TCC AAC TAG 3\'

c. DNA chain: 3\' TAC GTC TCC AGC GGA GAT CTT TTC CGG TCG CAA CTG AGG TTG ATC 5\'

Transcript mRNA: 5\' AUG CAG AGG UCG CCU CUA GAA AAG GCC AGC GUU GAC UCC AAC UAG 3\'

d. Polypeptide: Met- Gln- Arg-Ser-Pro-Leu-Glu-Lys- Ala- Ser-Val-Asp-Ser-Asn-Stop