Concept explainers
To review:
DNase I is a restriction endonuclease which cuts the DNA but cannot cut the DNA that is protected by bound proteins. Human DNA is isolated, exposed of its non-histone proteins, and mixed with DNase I. Removal of samples carried after 30 minutes, 1 hour, and 4 hours and allowed to run separately in gel electrophoresis. The resulting gel is stained to make all DNA fragments in it visible, and the results are shown in the figure. The size of DNA fragment in base pairs (bp) is estimated by the scale to the left of the gel.
On the basis of the above information, following questions are asked:
a. Based on the gel results, speculate why longer DNase I treatment produces different results.
b. To conclude about the organization of chromatin in the human genome from this gel.
Introduction:
When DNA interacts with enzyme (proteins), it induces changes in the DNA. This interaction can be analyzed by the biochemical methods such as gel electrophoresis. DNase I is an endonuclease. It cleaves the DNA at the phosphodiester bond which is adjacent to pyrimidine
Want to see the full answer?
Check out a sample textbook solutionChapter 10 Solutions
Genetic Analysis: An Integrated Approach (3rd Edition)
- The topoisomerase enzyme catalyzes the interconversion of the relaxed and supercoiled forms of DNA by making transient breaks in one or both DNA strands. What is the difference between I and II?arrow_forwardA 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.arrow_forwardDuring 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? (i)DNA polymerase IIIii) Helicasearrow_forward
- How often, on average, will the endonuclease AluI, which cleaves the sequence 5’ AGCT 3’, cut normal DNA (assume equal amounts of each base)? (In other words, what will the average fragment size be after cutting?) Group of answer choices 256 bases 12 bases 40 bases 16 bases none of thesearrow_forwardUsing the figure below, what is molecule "A" (type a 1, 2 or 3 in the blank) nuclease ligase DNA polymerase What is the function of molecule "A"? to separate the double helix into two to piece together the Okazaki segments to copy the new DNA strand to the old strand by complementary base pairing Using the figure below, what is molecule "G" (type a 1, 2 or 3 in the blank) nuclease ligase DNA polymerase What is the function of molecule "G"? to separate the double helix into two to piecearrow_forwardUsing the figure below, what is molecule "A" (type a 1, 2 or 3 in the blank) nuclease ligase DNA polymerase What is the function of molecule "A"? to separate the double helix into two to piece together the Okazaki segments to copy the new DNA strand to the old strand by complementary base pairing Using the figure below, what is molecule "G" (type a 1, 2 or 3 in the blank) nuclease ligase DNA polymerase What is the function of molecule "G"? to separate the double helix into two to piece together the Okazaki segments to copy the new DNA strand to the old strand by complementary base pairing Which of the following statements best describes why one of the daughter strands is synthesized in pieces? the enzymes that synthesize DNA are slower that the enzymes that unwind the double helix and this produces 'lagging time' the enzymes that synthesize DNA can only do so in a 5' --->3' direction this figure illustrates a eukaryotic cell since prokaryotic cells do not synthesize DNA…arrow_forward
- In a standard procedire, when writing and reading base sequences for nucleic acids (both DNA and RNAs) always to specify base sequence in 5' > 3' direction unless otherwise directed 1. From the base sequence 5' A-T-G-C-C-A 3' in a DNA template strand, determine the base sequence in hnRNA synthesized from the DNA template strand 2. From the base sequence 5' T-A-A- C-C-T 3' in a DNA template strand, determine the base sequence in hnRNA synthesized from the DNA template strandarrow_forwardDeamination of adenine results in the formation of hypoxanthine. Hypoxanthine selectively base pairs with cytosine. If this error is not corrected, what base pair can the original A·T base pair be converted to after cycles of DNA replication?a) G·C b) C·G c) T·A d) A·Garrow_forwardThe restriction enzyme Alu I cleaves at the sequence 5’-AGCT- 3' , and Not I cleaves at 5' -GCGGCCGC-3'. What would be the average distance between cleavage sites for each enzyme on digestion of double-stranded DNA? Assume that the DNA contains equal proportions of A, G, C, and T.arrow_forward
- What enzymatic features of DNA polymerase prevent it from replicating one of the DNA strands at the ends of linear chromosomes? Compared with DNA polymerase, how is telomerase different in its ability to synthesize a DNA strand? What does telomerase use as its template for the synthesis of a DNA strand? How does the use of this template result in a telomere sequence that is tandemly repetitive?arrow_forwardDNA polymerase I, DNA ligase, and topoisomerase I catalyze the formation of phosphodiester bonds. What is the activated intermediate in the linkage reaction catalyzed by each of these enzymes? What is the leaving group?arrow_forwardNucleosomes can be assembled onto defined DNA segments. When a particular 225-bp segment of human DNA was used to assemble nucleosomes and then incubated with micrococcal nuclease, which digests DNA that is not located within the nucleosome, uniform fragments 147 bp in length were generated. Subsequent digestion of these fragments with a restriction enzyme that cuts once within the original 225-bp sequence produced two well-defined bands at 37 bp and 110 bp. Why do you suppose two well-defined fragments were generated by restriction digestion, rather than a range of fragments of different sizes? How would you interpret this result?arrow_forward
- Human Anatomy & Physiology (11th Edition)BiologyISBN:9780134580999Author:Elaine N. Marieb, Katja N. HoehnPublisher:PEARSONBiology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStaxAnatomy & PhysiologyBiologyISBN:9781259398629Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa StouterPublisher:Mcgraw Hill Education,
- Molecular Biology of the Cell (Sixth Edition)BiologyISBN:9780815344322Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter WalterPublisher:W. W. Norton & CompanyLaboratory Manual For Human Anatomy & PhysiologyBiologyISBN:9781260159363Author:Martin, Terry R., Prentice-craver, CynthiaPublisher:McGraw-Hill Publishing Co.Inquiry Into Life (16th Edition)BiologyISBN:9781260231700Author:Sylvia S. Mader, Michael WindelspechtPublisher:McGraw Hill Education