arvas Question 16 10 pts You have discovered several mutant strains of E. co. Ea
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arvas Question 16 10 pts You have discovered several mutant strains of E. co. Each mutant exhibits a defect in DNA replication. To assess the defect in each strain, you isolate and analyze the double-stranded nucleic aids. From the results below, list the replication if an enzyme has multiple activities, specify which activity is affected). For example, if a strain's nucleic acid consisted of one very long DNA molecule on one strand and a molecule of DNA on the other strand that contained polymerase IIl wasn't functioning, because proofreading apparently hadn't occurred during replication. numerous mismatched bases, you might conclude that the 3' to 5' exonuclease activity of DNA a) Strain 1: the nucleic acid consists of a very long DNA molecule on one strand, and other strand bi Strain 2: the nucleic acid consists of two very long DNA molecules, each comprising one strand of the double-stranded nucleic acid c) Strain 3: the nucleic acid consists of a very long DNA molecule on one strand and numerous short stretches of nucleic acid consisting of RNA joined to DNA on the other strand. Strain 4: The nucleic acid consists of a very long DNA molecule on one strand and numerous short on the other strand. molecules of DNA only e) Strain 5: The nucleic acid consists of very long molecules of single-stranded DNA only.Explanation / Answer
a.DNA polymerase III holoenzyme that addes nucleotides to the RNA primer is non functional as RNA primer are present but no synthesis has started.
b.Dna C helicase and Dna B helicase that function to unwind the DNA double helix has become non functional.
c.Since the RNA is joined to DNA on the other strand it means that RNase and DNA polymerase I (exonulcease) are non functional.( RNase and DNA polymerase 1 function to degrade the RNA primers)
d.Numerous short molecules of DNA on the other strand (okazaki fragments)indicates that the DNA fragments are not joined which is due to non functional DNA ligase enzyme( DNA ligase enzyme functions to join the okazaki fragments).
e.This means that the double helix strands have unwinded but replication is not being started.This is due to the non functional DnaG primase enzyme that functions to starts the replication process by adding RNA primer on the single strands so that DNA polymerase III holoenzyme can begin the elogation process.
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