Q29-26E - Organic Chemistry (Mcmurry)

Question

For what amino acids do the following ribonucleotide triplets code?

(a) AAU 

(b) GAG 

(c) UCC 

(d) CAU

Step-by-Step Solution

Answer

In solution (a), the amino acid for AAU triplet code is Asn.

In solution (b), the amino acid for GAG triplet code is Glu.

In solution (c), the amino acid for UCC triplet code is Ser.

In solution (d), the amino acid for CAU triplet code is His.

Step 1: Introduction

Messenger RNA (mRNA) is responsible for directing the creation of hundreds of different peptides and proteins that organisms require. Protein biosynthesis is carried out on ribosomes, which are tiny granular particles made up $\mathbf{60}\mathbf{\%}$of ribosomal RNA and $\mathbf{40}\mathbf{\%}$ protein that are found in the cytoplasm of a cell.

The unique sequence of mRNA creates a message that specifies the amino acid residue sequences that must be linked, referred to as "codon". Each "word," or codon, is made up of three ribonucleotides that are unique to a certain amino acid. In a process known as translation, the message encoded in mRNA is read by transfer RNA (tRNA).

Step 2: Codon assignment of base triplet

The direction of writing the bounded amino acid sequence is always the same . tRNA, which possesses the corresponding anticodon base, reads the codon sequence on mRNA.

The tabulation is,

Step 3: Explanation for (a).

The given triplet code is,

AAU

The first base is A, the second base is A and the third base is U.

From the assignment table, the code indicates “Asn”.

Step 4: Explanation for (b).

The given triplet code is,

GAG

The first base is G, the second base is A and the third base is G.

From the assignment table, the code indicates “Glu”.

Step 5: Explanation for (c).

The given triplet code is,

UCC

The first base is U, the second base is C and the third base is C.

From the assignment table, the code indicates “Ser”.

Step 6: Explanation for (d)

The given triplet code is,

CAU

The first base is C, the second base is A and the third base is U.

From the assignment table, the code indicates “His”.