Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 12: Problem 14

A glycine residue exists at position 210 of the tryptophan synthetase enzyme of wild-type \(E .\) coli. If the codon specifying glycine is GGA, how many single-base substitutions will result in an amino acid substitution at position 210 , and what are they? How many will result if the wild-type codon is GGU?

Short Answer

Expert verified
Answer: For both GGA and GGU glycine codons, 6 out of 9 possible single-base substitutions result in an amino acid substitution at position 210.

Step by step solution

01

Identify possible single-base substitutions for GGA codon

In this step, we will list all possible single-base substitutions for the given glycine codon GGA. We have three positions to change and 3 possible nucleotides to change them to (excluding the original nucleotide), so we get the following 9 substitutions: - Position 1: GGA -> AGA, TGA, or CGA - Position 2: GGA -> GAA, GTA, or GCA - Position 3: GGA -> GGG, GGT, or GGC
02

Determine amino acids corresponding to the new codons

Now, we'll use an amino acid reference table to determine the amino acids corresponding to the new codons: - AGA: Arginine - TGA: Stop codon - CGA: Arginine - GAA: Glutamic acid - GTA: Valine - GCA: Alanine - GGG: Glycine - GGT: Glycine - GGC: Glycine
03

Count how many substitutions result in a different amino acid

In this step, we will count the number of substitutions that result in an amino acid different from glycine: - AGA: Arginine (Different) - TGA: Stop codon (Different) - CGA: Arginine (Different) - GAA: Glutamic acid (Different) - GTA: Valine (Different) - GCA: Alanine (Different) - GGG: Glycine (Same) - GGT: Glycine (Same) - GGC: Glycine (Same) For the GGA codon, a total of 6 out of 9 possible single-base substitutions result in an amino acid substitution at position 210. Now, let's perform the same steps for the GGU codon.
04

Identify possible single-base substitutions for GGU codon

In this step, we will list all possible single-base substitutions for the given glycine codon GGU: - Position 1: GGU -> AGU, TGU, or CGU - Position 2: GGU -> GAU, GTU, or GCU - Position 3: GGU -> GGG, GGT, or GGC
05

Determine amino acids corresponding to the new codons

Now, we'll use an amino acid reference table to determine the amino acids corresponding to the new codons: - AGU: Serine - TGU: Cysteine - CGU: Arginine - GAU: Aspartic acid - GTU: Valine - GCU: Alanine - GGG: Glycine - GGT: Glycine - GGC: Glycine
06

Count how many substitutions result in a different amino acid

In this step, we'll count the number of substitutions that result in an amino acid different from glycine: - AGU: Serine (Different) - TGU: Cysteine (Different) - CGU: Arginine (Different) - GAU: Aspartic acid (Different) - GTU: Valine (Different) - GCU: Alanine (Different) - GGG: Glycine (Same) - GGT: Glycine (Same) - GGC: Glycine (Same) For the GGU codon, a total of 6 out of 9 possible single-base substitutions result in an amino acid substitution at position 210 as well. In conclusion, for both GGA and GGU glycine codons, 6 out of 9 possible single-base substitutions result in an amino acid substitution at position 210.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

In studies of frameshift mutations, Crick, Barnett, Brenner, and Watts-Tobin found that either three nucleotide insertions or deletions restored the correct reading frame. (a) Assuming the code is a triplet, what effect would the addition or loss of six nucleotides have on the reading frame? (b) If the code were a sextuplet (consisting of six nucleotides), would the reading frame be restored by the addition or loss of three, six, or nine nucleotides?

In studies of the amino acid sequence of wild-type and mutant forms of tryptophan synthetase in \(E .\) coli, the following changes have been observed: Determine a set of triplet codes in which only a single-nucleotide change produces each amino acid change.

When the amino acid sequences of insulin isolated from different organisms were determined, some differences were noted. For example, alanine was substituted for threonine, serine was substituted for glycine, and valine was substituted for isoleucine at corresponding positions in the protein. List the single-base changes that could occur in triplets to produce these amino acid changes.

Most proteins have more leucine than histidine residues but more histidine than tryptophan residues. Correlate the number of codons for these three amino acids with this information.

One form of posttranscriptional modification of most eukaryotic RNA transcripts is the addition of a poly-A tail at the \(3^{\prime}\) -end. The absence of a poly-A tail leads to rapid degradation of the transcript. Poly-A tails of various lengths are also added to many bacterial RNA transcripts where, instead of promoting stability, they enhance degradation. In both cases, RNA secondary structures, stabilizing proteins, or degrading enzymes interact with poly-A tails. Considering the activities of RNAs, what might be the general functions of \(3^{\prime}\) -polyadenylation??
See all solutions

Recommended explanations on Biology Textbooks

Microbiology

Read Explanation

Chemistry of Life

Read Explanation

Bioenergetics

Read Explanation

Biological Structures

Read Explanation

Ecology

Read Explanation

Organ Systems

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free