Concept explainers
Genomic DNA from the nematode worm Caenorhabditiselegansis organized by nucleosomes in the manner typical of eukaryotic genomes, with
Approximately what range of DNA fragment sizes do you expect to see in the stained electrophoresis gel? How many bands will be visible on the gel?
Explain the origin of DNA fragments seen in the gel.
How do the expected results support the
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Genetic Analysis: An Integrated Approach (2nd Edition)
- Number of Okazaki Fragments in E. coli and Human DNA Replication Approximately how many Okazaki fragments are synthesized in the course of replicating an E. coli chromosome? How many in replicating an “average� human chromosome?arrow_forwardFunctional Consequences of Y-Family DNA Polymerase Structure The eukaryotic translesion DNA polymerases fall into the Y family of DNA polymerases. Structural studies reveal that their fingers and thumb domains are small and stubby (see Figure 28.10). In addition, Y-family polymerase active sites are more open and less constrained where base pairing leads to selection of a dNTP substrate for the polymerase reaction. Discuss the relevance of these structural differences. Would you expect Y-family polymerases to have 3-exonuclease activity? Explain your answer.arrow_forwardHeteroduplex DNA Formation in Recombination From the information in Figures 28.17 and 28.18, diagram the recombinational event leading to the formation of a heteroduplex DNA region within a bacteriophage chromosome.arrow_forward
- Multiple Replication Forks in E. coli I Assuming DNA replication proceeds at a rate of 750 base pairs per second, calculate how long it will take to replicate the entire E. coli genome. Under optimal conditions, E. coli cells divide every 20 minutes. What is the minimal number of replication forks per E. coli chromosome in order to sustain such a rate of cell division?arrow_forwardHomologous Recombination, Heteroduplex DNA, and Mismatch Repair Homologous recombination in E. coli leads to the formation of regions of heteroduplex DNA. By definition, such regions contain mismatched bases. Why doesn’t the mismatch repair system of E. coli eliminate these mismatches?arrow_forwardMultiple Replication Forks in E. coli II On the basis of Figure 28.2, draw a simple diagram illustrating replication of the circular E. coli chromosome (a) at an early stage, (b) when one-third completed, (c) when two-thirds completed, and (d) when almost finished, assuming the initiation of replication at oriC has occurred only once. Then, draw a diagram showing the E. coli chromosome in problem 3 where the E. coli cell is dividing every 20 minutes.arrow_forward
- Prokaryotes have a single circular chromosome while eukaryotes have linear chromosomes. Describe one advantage and one disadvantage to the eukaryotic genome packaging compared to the prokaryotes.arrow_forwardLet’s suppose you have isolated chromatin from some bizarreeukaryote with a linker region that is usually 300–350 bp inlength. The nucleosome structure is the same as in other eukaryotes.If you digested this eukaryotic organism’s chromatin with ahigh concentration of DNase I, what would be your expectedresults?arrow_forward4a in context to taking genomic DNA from eukaryotic cells and randomly shearing it into pieces of a constant size, why do some of the genomic DNA fragments re-nature so much more quickly than other fragmentsarrow_forward
- Under physiological conditions, DNA ordinarily formsB-DNA. However, RNA hairpins and DNA-RNAhybrids adopt the structure of A-DNA. Considering thestructural differences between DNA and RNA, explain thisphenomenon.arrow_forwardEthanol (CH3-CH2-OH) is miscible in water because it is able to form hydrogen bonds with itself and other molecules. However, its structure only allows it to form 1-2 hydrogen bonds. This is one reason why even low concentrations of ethanol in solution are lethal for cells. Based on this information, explain why we can use high concentrations of ethanol to precipitate DNA out of solution. Also, describe/predict the effects of increasing concentrations of ethanol in (and around) a cell on macro-molecular interactions (i.e. on weak bonds). Finally, it is possible to select for yeast that are tolerant to increased concentrations of ethanol. Give an example of a physiological change in yeast cells that might make them resistant to ethanol.arrow_forwardWhat two basepair changes can occur when G tautomerizes to the enol form? Recall that the tautomerization can occur when G is a free dNTP prior to DNA replication or when G is incorporated into dsDNA just before DNA replication. Draw both of these bp changes out. Are they transitions or transversions?arrow_forward
- BiochemistryBiochemistryISBN:9781305577206Author:Reginald H. Garrett, Charles M. GrishamPublisher:Cengage LearningBiology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStax