Chapter 34 - DNA Replication

During replication in E. coli, the removal of Okazaki RNA primers in the lagging strand and resolution of the resulting gaps in DNA are achieved by only DNA ligase. DNA polymerase III and DNA ligase. only DNA polymerase III. DNA polymerase I and DNA ligase. only DNA polymerase I.

DNA polymerase I and DNA ligase.

Arrange the steps of DNA replication in the correct order. RNA primers are removed RNA primers are added Single stranded DNA binding proteins bind to each template strand Helicase unwinds the double helix DNA ligase joins the fragments together DNA polymerase synthesizes DNA

Helicase unwinds the double helix Single stranded DNA binding proteins bind to each template strand RNA primers are added DNA polymerase synthesizes DNA RNA primers are removed DNA ligase joins the fragments together

Which of the statements regarding DNA replication are true? New nucleotides add to the 5′ hydroxyl of the growing DNA molecule. Leading strand fragments (Okazaki fragments) are synthesized semi‑discontinuously and must be joined by DNA ligase. Replication takes place in the 5′ to 3′ direction on the leading strand and in the′3′ to 5′ direction on the lagging strand. Replication usually takes place in the 5′ to 3′ direction. Eukaryotic chromosomes have more than one origin of replication.

Replication usually takes place in the 5′ to 3′ direction. Eukaryotic chromosomes have more than one origin of replication.

Cancer is characterized by uncontrolled cell division. Cell division is preceded by DNA replication. Several proteins of the DNA‑replication machinery can be targets for chemotherapeutic agents. One such protein is topoisomerase. Select the effects that result from any degree of inhibition of topoisomerase. The RNA primer is not removed, leading to DNA-RNA composites. The double helix is not unwound, halting DNA replication. Single‑stranded breaks form, leading to DNA fragmentation .Supercoils accumulate, resulting in chromosomal instability. The double helix reanneals to its natural state, stopping DNA replication.

Single‑stranded breaks form, leading to DNA fragmentation .Supercoils accumulate, resulting in chromosomal instability.

As DNA is replicated, both continuous and discontinuous replication occur. Discontinuous replication is the result of which specific feature of DNA? minor groove bonds between base pairs antiparallel strands directionality of DNA polymerase purine and pyrimidine nucleotides

antiparallel strands

For DNA replication to occur, the two strands of the double helix must be physically separated. This separation is accomplished through the use of topoisomerase enzymes. helicase enzymes. single‑stranded‑binding (SSB) protein. primase. breaking and rejoining of one of the DNA strands.

helicase enzymes.

During the replication of DNA, both strands are simultaneously synthesized in a continuous manner. both strands are synthesized continuously, but the lagging strand is synthesized only after the leading strand has been completely replicated. one strand is synthesized continuously and the other is synthesized in short segments. one strand is synthesized in a continuous manner and the other is synthesized by reverse transcription. both stands are simultaneously synthesized in short pieces that are later joined by DNA ligase.

one strand is synthesized continuously and the other is synthesized in short segments.

DNA replication in E. coli begins at a unique site called the oriD locus. Ter site. polymerase site. origin of replication. origin of responsiveness.

origin of replication.

There are five DNA polymerases in E. coli. Which is NOT a function of E. coli DNA polymerases? DNA repair primer formation primer removal exonuclease activity DNA replication

primer formation

Which compound is released during the addition of deoxyribonucleotides to the nascent DNA chain? pyrophosphate (PPi) dNTP ATP AMP Okazaki fragments

pyrophosphate (PPi)

DNA replication involves multiple steps that require different enzymes. Which process does primase catalyze in DNA replication? bond formation that joins nicked DNA strands synthesis of a short RNA sequence that initiates DNA synthesis relaxes twists and knots created by DNA supercoiling addition of DNA to the RNA primer

synthesis of a short RNA sequence that initiates DNA synthesis

The primase enzyme in E. coli acts as the recognition site to which DNA polymerases bind to start the replication process. synthesizes a short stretch of DNA that is complementary to a part of the template DNA strand. ligates the nicks formed by discontinuous replication along the lagging strand. synthesizes a short stretch of RNA that is complementary to a part of the template DNA strand. replaces the RNA primers used to initiate DNA replication with DNA polymerase.

synthesizes a short stretch of RNA that is complementary to a part of the template DNA strand.

Which factor accounts for the increased rate of DNA synthesis necessary for replication in eukaryotic cells as compared to that in prokaryotes? the presence of telomere DNA the ability to replicate in both the 5′ to 3′ and 3′ to 5′ directions the presence of multiple origins at which replication can take place at the same time the use of different chemistry by the DNA polymerase enzymes the lack of need for a proofreading mechanism to correct errors

the presence of multiple origins at which replication can take place at the same time