Proliferating Cell Nuclear Antigen (PCNA) is a ring-shaped protein that forms a clamp around DNA. DNA polymerase binds to the outside of the PCNA clamp, keeping the polymerase tightly associated with DNA during replication. PCNA is a homo-oligomer, each subunit is shown as a different color in the image below. a) In the lab, you purify PCNA from mouse tissue. Based on the protein sequence, the extinction coefficient for a single PCNA molecule at 280 nm is e = 15,930 M cm. What is the extinction coefficient for the homo-oligomeric PCNA clamp? b) Your purified sample of murine PCNA absorbs 72% of incident light at 280 nm using a standard 1 cm path length cuvette. What is the concentration in micromolar?

Proliferating Cell Nuclear Antigen (PCNA) is a ring-shaped protein that forms a clamp around DNA. DNA polymerase binds to the outside of the PCNA clamp, keeping the polymerase tightly associated with DNA during replication. PCNA is a homo-oligomer, each subunit is shown as a different color in the image below. a) In the lab, you purify PCNA from mouse tissue. Based on the protein sequence, the extinction coefficient for a single PCNA molecule at 280 nm is e = 15,930 M cm. What is the extinction coefficient for the homo-oligomeric PCNA clamp? b) Your purified sample of murine PCNA absorbs 72% of incident light at 280 nm using a standard 1 cm path length cuvette. What is the concentration in micromolar?

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter11: Genome Alterations: Mutation And Epigenetics

Section: Chapter Questions

Problem 18QP: Replication involves a period of time during which DNA is particularly susceptible to the...

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Replication involves a period of time during which DNA is particularly susceptible to the introduction of mutations. If nucleotides can be incorporated into DNA at a rate of 20 nucleotides/second and the human genome contains 3 billion nucleotides, how long will replication take? How is this time reduced so that replication can take place in a few hours?
A solution contains DNA polymerase and the Mg ²+ salts of dATP, dGTP, dCTP, and TTP. The following DNA molecules are added to aliquots of this solution. Which of them would lead to DNA synthesis? (a) A single-stranded closed circle containing 1000 nucleotide units. (b) A double-stranded closed circle containing 1000 nucleotide pairs. (c) A single-stranded closed circle of 1000 nucleotides base-paired to a linear strand of 500 nucleotides with a free 3' -OH terminus. (d) A double-stranded linear molecule of 1000 nucleotide pairs with a free 3’-OH group at each end.
It was once thought that the DNA polymerase machinery moves along DNA in a manner analogous to a train on a track. Current evidence indicates that the polymerizing machinery is instead stationary and that the DNA strands are pumped through the complex. What advantages does this stationary mechanism have?
The anti-viral drug Acyclovir is a nucleotide analog that is lacking the 3’ OH group which is required to form a 3’→5’ phosphodiester bond. This drug is ineffective against DNA polymerases with proofreading abilities, which is why human DNA polymerases are not targeted. Acyclovir can be used to treatsevere cases of Epstein-Barr viral (EBV) infection, but has little to no effect under non-severe infections. Based on this information, EBV will use ________ DNA polymerase during severe infections and __________ DNA polymerase during non-severe infections. Human; Human EBV; Human EBV; EBV Human; EBV
A reaction mixture contains DNA polymerase, the four dNTPs, and one of the DNA molecules whose structure is represented below. Which reaction mixtures generate PPi?
Which statement below best describes what these data might have demonstrated to Kornberg about the process of replication? CHOOSE ONE and explain the rationale behind your answer in a minimum of four sentences. A. Products of replication are DNA polymers. B. DNA Pol I-mediated replication is a high-fidelity (i.e., no mistakes) process C. DNA Pol III-mediated replication gives rise to two daughter strands, one which is made of only the original templates, and one of which is only newly synthesized polymer. D. In DNA, all 4 classes of nitrogenous bases are more or less equally represented E. A pairs with T and C pairs with G
the human immunodeficiency virus HIV uses RNA rather than DNA to encode genetic information. During infection, however, HIV uses an enzyme known as reverse transcriptase to generate double-stranded DNA. Generally speaking, how would the enzyme generate a double strand of DNA from a single strand of RNA?
Depurination of purine bases results in an apurinic site. Assume a single depurination event occurs in the GC base pair of the sequence below and is not repaired. Then, if two rounds of replication occur, which of the following DNA sequences will exist after two rounds of replication? Remember that when DNA polymerases encounter an apurinic site, most often an A is incorporated into the newly synthesized strand. Assume this is true for the sequence below. ...TACT... ...ATGA... Question 7 Select one or more: ...TAGT... ...ATCA... 1. ...TACT... ...ATGA... 2. ...TAAT... ...ATTA... 3. ...TAAT... ...AT_A... 4. ...TA_T... ...ATAA... 5. ...TATT... ...ATAA...
Depurination of purine bases results in an apurinic site. Assume a single depurination event occurs in the GC base pair of the sequence below and is not repaired. Then, if two rounds of replication occur, which of the following DNA sequences will exist after two rounds of replication? Remember that when DNA polymerases encounter an apurinic site, most often an A is incorporated into the newly synthesized strand. Assume this is true for the sequence below. ...TACT... ...ATGA... Question 7 Select one or more: a) ...TAGT... ...ATCA... b) ...TACT... ...ATGA... c)...TAAT... ...ATTA... d) ...TAAT... ...AT_A... . e) ...TA_T... ...ATAA... f)...TATT... ...ATAA...
Agarose gels with different average pore sizes areneeded to separate DNA molecules of different sizeclasses. For example, optimal separation of 1100 bpand 1200 bp fragments would require a gel with alarger average pore size than optimal separation of8500 bp and 8600 bp fragments. How do you thinkthat scientists prepare gels of different average poresizes? (Hint: Agarose gels are made in a mannersimilar to gelatin desserts such as JELL-O.)
During high stress environments, it has been found that some bacteria activate a genetic mechanism that allows them to incorporate more mutations into the DNA during replication. Would the following two enzymes be impacted by such a mechanism? In each case, provide a reason for your answer. i) DNA polymerase IIIii) Helicase
Assume that the sequence of bases shown below is presenton onenucleotide chain of a DNA duplex and that the chain has openedup at a replication fork. Synthesis of an RNA primer occurs on thistemplate starting at the base that is underlined.(a) If the RNA primer consists of eight nucleotides, what is itsbase sequence?(b) In the intact RNA primer, which nucleotide has a free 3'-OHterminus?3'.......GGCTACCTGGATTCA....5'