Skip to main content
Pearson+ LogoPearson+ Logo
Ch. 9 - The Molecular Biology of Translation
Sanders - Genetic Analysis: An Integrated Approach 3rd Edition
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Not the one you use?Change textbook
Chapter 9, Problem 21a

In an experiment to decipher the genetic code, a poly-AC mRNA (ACACACAC...) is synthesized. What pattern of amino acids would appear if this sequence were to be translated by a mechanism that reads the genetic code as
A doublet without overlaps?

Verified step by step guidance
1
Understand the problem: The poly-AC mRNA sequence alternates between adenine (A) and cytosine (C). The question asks us to determine the amino acid pattern if the genetic code is read as doublets (two nucleotides at a time) without overlaps.
Recall the concept of codon translation: Normally, the genetic code is read in triplets (three nucleotides at a time). However, in this problem, the mechanism reads doublets. Each doublet corresponds to a specific amino acid based on the experimental genetic code provided.
List all possible doublets from the poly-AC sequence: Since the sequence alternates as ACACAC..., the possible doublets are 'AC' and 'CA'. These doublets repeat throughout the sequence.
Determine the amino acids corresponding to the doublets: Using the experimental genetic code (which would need to be provided or referenced), identify the amino acids that correspond to 'AC' and 'CA'. For example, if 'AC' codes for amino acid X and 'CA' codes for amino acid Y, the pattern would alternate between X and Y.
Describe the resulting amino acid pattern: Based on the translation of the doublets, the amino acid sequence would alternate between the amino acids corresponding to 'AC' and 'CA'. This pattern would repeat throughout the length of the mRNA.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
3m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Genetic Code

The genetic code is a set of rules that defines how sequences of nucleotides in DNA and RNA are translated into amino acids, the building blocks of proteins. It consists of codons, which are triplets of nucleotides, each corresponding to a specific amino acid or a stop signal during protein synthesis.
Recommended video:
Guided course
11:43
The Genetic Code

Translation Mechanism

Translation is the process by which ribosomes synthesize proteins using mRNA as a template. In this context, the mechanism refers to how the ribosome reads the mRNA sequence to assemble amino acids into a polypeptide chain, which can occur in different reading frames depending on the codon structure.
Recommended video:
Guided course
07:58
Translation initiation

Doublet Reading

Doublet reading refers to interpreting the mRNA sequence in pairs of nucleotides instead of the standard triplet codons. This approach alters the way amino acids are assigned to the mRNA sequence, leading to a different pattern of amino acids being produced, as each pair of nucleotides corresponds to a specific amino acid.
Recommended video:
Guided course
08:55
Sequencing Overview