Question

A protein is made up from the following amino acids: Gly-Phe-Lys-Pro-Met-Trp

1.) List the codons for the amino acids

2.) List the DNA base sequence that gave rise to this protein.

Answer 1

Given aminoacid sequence : Gly-Phe-Lys-Pro-Met-Trp.

(a) Glycine(Gly) – has four codons

GGU, GGC, GGA, GGG

Phenylalanine(phe) – has two codons

UUU, UUC

Lysine(Lys) – has two codons

AAA, AAG

Proline(Pro) – Has four codons

CCU, CCC, CCA, CCG

Methionine(Met) and Tryptophan (Trp) have only one codon; AUG and UGG.

AUG is the start codon.

(b) Protein synthesis begins with DNA, because it contains all the genetic information. Within DNA, there are sequences of nucleotides (A, T, G, C) that form a code to make proteins, a vital part of life. Proteins are made up of a sequence of 20 amino acids. These amino acids link together to form a polypeptide chain, and then folds into a three dimensional structure.

DNA --> RNA --> Protein.

First we can write mRNA sequence from the codons;

GGU-UUU-AAA-CCU-AUG-UGG.

Then the DNA sequence

CCA-AAA-TTT-GGA-TAC-ACC