31. Several temperature-sensitive mutant strains of Escherichia coli display the

Question

31. Several temperature-sensitive mutant strains of Escherichia coli display the following characteristics at the higher, restrictive temperature. For each one, state ONE protein you think is altered by the mutation in its corresponding gene. Justify why you think these characteristics would be associated with such a mutation. A) Strain 1-Okazaki fragments accumulate and DNA synthesis is never completed. B) Strain 2-No initiation of replication occurs. Strain 3- The replicated DNA contains stretches of interspersed RNA and replication cannot be completed. C) 32. Analysis of a nucleic acid molecule indicates that the nitrogenous base uracil is present. No other information is available about the structure or composition of the molecule. A) What kind of sugar would you expect to find in the nucleotides of this molecule? If it is established that uracil makes up 18% of the bases in the molecule and that the molecule is linear and double-stranded, what are the percentages of each of the other bases? (Show work for partial credit) B) C) If you also had a molecule of the same base pair length as that in (B), but it was only 10% uracil and you exposed both double-stranded molecules to slowly increasing temperature, which molecule would show complete disruption of its double helix (i.e. melting) first and why?

Explanation / Answer

31. A. DNA ligase activity is affected, due to which there is no linkage of DNA occur.

B. Primase is affected, due to which primer is not attached to initiate the reaction

C. DNA gyrase is affected,

32. A. uracil is present in RNA, thus ribose sugar is expected

  

Related Questions

Navigate

• Browse (All)
• Browse 3
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.