Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 12: Problem 9

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.

Short Answer

Expert verified
Answer: One possible set of triplet codes for each amino acid change is: 1. Arginine (Arg) to Histidine (His): CGU -> CAU 2. Asparagine (Asn) to Aspartic acid (Asp): AAU -> GAU 3. Phenylalanine (Phe) to Leucine (Leu): UUU -> UUA 4. Serine (Ser) to Proline (Pro): UCU -> CCU

Step by step solution

01

List the amino acid changes

Write down the amino acid changes given in the problem: 1. Arginine (Arg) to Histidine (His) 2. Asparagine (Asn) to Aspartic acid (Asp) 3. Phenylalanine (Phe) to Leucine (Leu) 4. Serine (Ser) to Proline (Pro)
02

Determine corresponding codons in the genetic code

Identify the codons for the amino acids involved in the changes using the genetic code table: 1. Arginine (Arg): CGU, CGC, CGA, CGG, AGA, AGG Histidine (His): CAU, CAC 2. Asparagine (Asn): AAU, AAC Aspartic acid (Asp): GAU, GAC 3. Phenylalanine (Phe): UUU, UUC Leucine (Leu): UUA, UUG, CUU, CUC, CUA, CUG 4. Serine (Ser): UCU, UCC, UCA, UCG, AGU, AGC Proline (Pro): CCU, CCC, CCA, CCG
03

Find single-nucleotide changes matching amino acid changes

Compare codons of the original and mutated amino acids to find possible single-nucleotide changes: 1. Arginine (Arg) to Histidine (His): CGU -> CAU 2. Asparagine (Asn) to Aspartic acid (Asp): AAU -> GAU 3. Phenylalanine (Phe) to Leucine (Leu): UUU -> UUA 4. Serine (Ser) to Proline (Pro): UCU -> CCU Note that there might be more than one possible set of triplet codes that satisfy the given conditions. However, we have found one set of triplet codes that require only a single-nucleotide change for each amino acid change as mentioned in the problem statement.
04

Final Answer

The set of triplet codes in which only a single-nucleotide change produces each amino acid change is: 1. Arginine (Arg) to Histidine (His): CGU -> CAU 2. Asparagine (Asn) to Aspartic acid (Asp): AAU -> GAU 3. Phenylalanine (Phe) to Leucine (Leu): UUU -> UUA 4. Serine (Ser) to Proline (Pro): UCU -> CCU

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

Messenger RNA molecules are very difficult to isolate from bacteria because they are quickly degraded. Can you suggest a reason why this occurs? Eukaryotic mRNAs are more stable and exist longer in the cell than do bacteria mRNAs. Is this an advantage or a disadvantage for a pancreatic cell making large quantities of insulin?

In this chapter, we focused on the genetic code and the transcription of genetic information stored in DNA into complementary RNA molecules. Along the way, we found many opportunities to consider the methods and reasoning by which much of this information was acquired. From the explanations given in the chapter, what answers would you propose to the following fundamental questions: (a) How did we determine the compositions of codons encoding specific amino acids? (b) How were the specific sequences of triplet codes determined experimentally? (c) How were the experimentally derived triplet codon assignments verified in studies using bacteriophage MS2? (d) How do we know that mRNA exists and serves as an intermediate between information encoded in DNA and its concomitant gene product? (e) How do we know that the initial transcript of a eukaryotic gene contains noncoding sequences that must be removed before accurate translation into proteins can occur?

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?

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

Ecosystems

Read Explanation

Biological Processes

Read Explanation

Communicable Diseases

Read Explanation

Plant Biology

Read Explanation

Chemistry of Life

Read Explanation

Cells

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