Chapter 26.10, Problem 26.20P

Interpretation Introduction

Interpretation:

The amino acids sequence for the given mRNA base sequence code has to be predicted.

Concept Introduction:

Codon: A sequence of three ribonucleotides in the mRNA chain that codes for a specific amino acid; also a three-nucleotide sequence that is a stop codon and stops translation.

Genetic code: The sequence of nucleotides, coded in triplets (codons) in mRNA that determines the sequence of amino acids in protein synthesis.

Translation: A tRNA molecule is a single polynucleotide chain held together by regions of base pairing in a partially helical structure. An amino acid is bonded to its specific tRNA by an ester linkage. Connecting specific amino acid at end of the tRNA is known as charging tRNA. Once done, tRNA is ready to be used in the protein synthesis.

At the other end of the tRNA, three anticodons are present which are complementary to the codons present in mRNA. Once the anticodons pairs off with codons, the amino acid at terminal end of the tRNA is delivered and attached to the growing protein chain.

Illustrated relationships are:

DNA informational strand : 5’ ATG  CCA   GTA  GGC  CAC   TTG   TCA  3’

DNA Template strand: 3’ TAC  GGT   CAT  CCG  GTG   AAC   AGT  5’

mRNA: 5’ AUG  CCA  GUA  GGC  CAC  UUG   UCA  3’

protein: Met    Pro     Val    Gly     His    Leu      Ser

Notice: 5’ end of the mRNA strand codes for the N-terminal amino acid, whereas the 3’ end of the mRNA strand codes for the C-terminal amino acid. Proteins are always written N-terminal to C-terminal, reading left to right.