Skip to main content
Ch. 10 - DNA Replication
Klug - Essentials of Genetics 10th Edition
Klug10th EditionEssentials of GeneticsISBN: 9780135588789Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoKlug 10th EditionCh. 10 - DNA ReplicationProblema 20d
Capitolo 10, Problema 20d

Several temperature-sensitive mutant strains of E. coli display the following characteristics. Predict what enzyme or function is being affected by each mutation.
Synthesis is very slow.

Guida verificata passo dopo passo
1
Step 1: Understand the context of temperature-sensitive mutants in E. coli. These mutants have enzymes or proteins that function normally at a permissive temperature but lose function at a restrictive (higher) temperature, causing observable phenotypic changes such as slow synthesis.
Step 2: Identify what 'synthesis is very slow' refers to. In E. coli, synthesis could mean DNA replication, RNA transcription, or protein translation. Since the problem is general, consider which enzyme or function is critical for the overall synthesis process.
Step 3: Recall that DNA replication requires DNA polymerase, RNA transcription requires RNA polymerase, and protein synthesis requires ribosomes and associated factors. Slow synthesis suggests a bottleneck in one of these key enzymatic activities.
Step 4: Since the problem states 'synthesis is very slow' without specifying which type, the most likely affected enzyme is DNA polymerase if the mutation affects DNA replication, or RNA polymerase if it affects transcription. Consider which enzyme's impairment would broadly slow down synthesis.
Step 5: Conclude that the mutation likely affects an enzyme essential for nucleic acid synthesis, such as DNA polymerase or RNA polymerase, causing the observed slow synthesis phenotype at the restrictive temperature.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
2m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Temperature-Sensitive Mutations

Temperature-sensitive mutations cause proteins to function normally at a permissive temperature but lose activity at a restrictive, usually higher, temperature. This allows researchers to study essential genes by observing phenotypic changes when the temperature shifts, revealing the role of the mutated enzyme or function.
Video consigliato:
Percorso guidato
10:48
Mutations and Phenotypes

Enzymes Involved in DNA Replication and Synthesis

DNA synthesis in E. coli requires enzymes like DNA polymerase, helicase, primase, and ligase. Mutations affecting these enzymes can slow or halt DNA replication, leading to slow synthesis. Identifying which enzyme is impaired helps explain the observed phenotype.
Video consigliato:
Percorso guidato
11:59
Steps to DNA Replication

Phenotypic Effects of Mutations on Cellular Processes

Mutations in genes encoding enzymes involved in critical processes like DNA replication manifest as observable phenotypes, such as slow synthesis. Understanding how mutations alter enzyme function helps predict which step in the pathway is affected and the resulting cellular consequences.
Video consigliato:
Percorso guidato
10:48
Mutations and Phenotypes
Pratica correlata
Domanda del libro di testo

Several temperature-sensitive mutant strains of E. coli display the following characteristics. Predict what enzyme or function is being affected by each mutation.

Newly synthesized DNA contains many mismatched base pairs.

669
views
Domanda del libro di testo

Several temperature-sensitive mutant strains of E. coli display the following characteristics. Predict what enzyme or function is being affected by each mutation.

Okazaki fragments accumulate, and DNA synthesis is never completed.

664
views
Domanda del libro di testo

Several temperature-sensitive mutant strains of E. coli display the following characteristics. Predict what enzyme or function is being affected by each mutation.

Supercoiled strands remain after replication, which is never completed.

706
views
Domanda del libro di testo

Many of the gene products involved in DNA synthesis were initially defined by studying mutant E. coli strains that could not synthesize DNA.

The dnaQ gene encodes the ε subunit of DNA polymerase. What effect is expected from a mutation in this gene?

491
views
Domanda del libro di testo

Many of the gene products involved in DNA synthesis were initially defined by studying mutant E. coli strains that could not synthesize DNA.

The dnaE gene encodes the α subunit of DNA polymerase III. What effect is expected from a mutation in this gene? How could the mutant strain be maintained?

614
views
Domanda del libro di testo

Several temperature-sensitive mutant strains of E. coli display the following characteristics. Predict what enzyme or function is being affected by each mutation.

No initiation occurs.

743
views