Temperature-sensitive mutations (ts) in E. coli are a type of conditional lethal mutation. A conditional lethal...

Temperature-sensitive mutations (ts) in E. coli are a type of conditional lethal mutation. A conditional lethal means that the mutation is only deadly under certain growth conditions, in this case when the temperature is increased to the restrictive temperature. The proteins are fully functional at the lower temperature (permissive). This type of mutation has been indispensable for studying the essential process of DNA replication. Mutants in proteins that are necessary for DNA replication can be classified into either quick-stop or slow-stop. Quick-stop mutants arrest DNA replication immediately, but slow-stop mutants halt after several minutes. Fill in the chart below to indicate which mutations will be slow and which quick when shifted to the higher, restrictive temperature. Assume that the E. coli have already started replication. Explain your answers. (6pts total: 1.5pts each)

Mutated Protein	Quick or slow?	Explanation
DNA gyrase
DnaA
DNA helicase
DNA ligase

Solutions

Expert Solution

gladiator answered 2 weeks ago

Next > < Previous

Related Solutions

(i) What is it about a mutant phenotype that classifies the mutation as “temperature-sensitive”?

a) (i) What is it about a mutant phenotype that classifies the mutation as “temperature-sensitive”? (ii) How is this type of phenotype explained by protein behaviour? b) Would the following types of mutations most likely have: severe effects, mild effects, or no effect on protein function? Briefly explain your answers. Note that there may be more than one correct answer, but you need only to give one sensible answer and explain your reasoning. (i) A nonsense mutation occurring in...

A strain of bacteria possesses a temperature sensitive mutation in the gene that encodes the rho...

A strain of bacteria possesses a temperature sensitive mutation in the gene that encodes the rho subunit. At high temperatures, rho is not functional. When these bacteria are switched to elevated temperature, which of the following effects would you expect to see? Explain your reasoning for accepting or rejecting these options. 1. Transcription does not take place at high temperature. 2. All RNA molecules produced are shorter then normal at high temperature. 3. Translation does not take place at high...

What would be the predicted phenotype of an E. coli mutant that contains a mutation in...

What would be the predicted phenotype of an E. coli mutant that contains a mutation in the cheA gene that abolishes its autophosphorylation activity? State the predicted phenotype. What kind of motility would it display?

A strain of E. coli carries a mutation that completely inactivates the enzyme encoded in the...

A strain of E. coli carries a mutation that completely inactivates the enzyme encoded in the gene. Several revertants, mutants of the mutant with partly or fully restored activity, were selected, and the amino acid sequence of the enzyme was determined. The only differences found were at position 10 in the polypeptide chain. Revertant 1 had Thr. Revertant 2 had Glu. Revertant 3 had Met. Revertant 4 had Arg. Assume that the initial mutation itself, as well as each revertant,...

why are temperature sensitive mutations more likely to involve missense over nonsense mutations? Please write clearly!

Operon. A particular E. Coli strain has a mutation in the operator of the tryptophan operon....

Operon. A particular E. Coli strain has a mutation in the operator of the tryptophan operon. How would you expect it would affect the functioning of the operon and the metabolism of the cells? What would happen if the trp operon had a mutation in the: 1. Promoter region? 2. Repressor gene (domain binding to tryptophan)? 3. Leader sequence TGGTGG? 4. Region 3 of Leader mRNA?

Consider a colony of E. coli cells that have a mutation in the lac I gene,...

Consider a colony of E. coli cells that have a mutation in the lac I gene, resulting in a LacR protein that cannot bind to allolactose. Describe the effect that this mutation will have on the lac operon in terms of βgal protein levels when the cells are grown in media containing lactose but no glucose. Explain your reasoning.

5) A mutation in E. coli designated polA1 was discovered that is deficient in DNA polyermase...

5) A mutation in E. coli designated polA1 was discovered that is deficient in DNA polyermase I activity Because of this, researchers hypothesized that DNA duplication may not be successful. Is their hypothesis true? If it was not, why? In what other way could this strain be deficient?

Mutations affecting methionine metabolism have been isolated in E. coli. An analysis of 4 strains in...

Mutations affecting methionine metabolism have been isolated in E. coli. An analysis of 4 strains in the presence and absence of methionine is presented below. A + indicates that methionine-producing enzymes are present; a - indicates that methionine-producing enzymes are not present. Strain. 1. metJ+ metA+ 2. metJ- metA+ 3. metJ+ metA- 4. metJ- metA- Methionine Present - + - - Methionine Absent + + - - A. Examine strain 1, the wild type. Is the methionine operon most likely...

Describe how you would identify genes responsible for transcription in E. coli by isolating mutations in...

Describe how you would identify genes responsible for transcription in E. coli by isolating mutations in their genes. Remember that these genes are required for cell viability. Include all the steps in the isolation of the mutants and also describe how you will differentiate the mutants you want from those in other genes necessary for viability. This includes giving me the expected result for mutants in the genes you want.

Subjects