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 (3rd Edition)
- The picture below depicts electron micrographs of the major levels of chromatin structure. Match each of the listed conditions with the most likely levels of chromatin structure under that condition.arrow_forwardFor a linear B-DNA molecule of 50,000 kb, calculate (a) the contour length and (b) the length of the DNA as packaged in nucleosomes with linker histones present.arrow_forwardHow many nucleosomes form the “width” of the 300 Angstrom fiber, in chromatin packaging?arrow_forward
- Mammals contain a diploid genome consisting of at least 109 bp. If this amount of DNA is present as chromatin fibers, where each group of 200 bp of DNA is combined with 9 histones into a nucleosome and each group of 6 nucleosomes is combined into a solenoid, achieving a final packing ratio of 50, determine (a) the total number of nucleosomes in all fibers, (b) the total number of histone molecules combined with DNA in the diploid genome, and (c) the combined length of all fibers.arrow_forwardwhat are we looking at in part (b)? Is this an11-nm fiber, a 30-nm fiber, or a 300-nm fiber? Does this DNAcome from a cell during M phase or interphase?arrow_forwardAn article entitled “Nucleosome Positioning at the Replication Fork” states: “both the ‘old’ randomly segregated nucleosomes as well as the ‘new’ assembled histone octamers rapidly position themselves (within seconds) on the newly replicated DNA strands” [Lucchini et al. (2002)]. Given this statement, how would one compare the distribution of nucleosomes and DNA in newly replicated chromatin? How could one experimentally test the distribution of nucleosomes on newly replicated chromosomes?arrow_forward
- Multiple 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_forwardMultiple 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_forwardUnder 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_forward
- Arrange the levels of chromatin packing from most "open" to most condensed (chromosome, loops, nucleosomes, heterochromatin, 30-nm chromatin fiber)arrow_forwardDescribe the structure of nucleosomes and the 30-nm fiber, andexplain how the 30-nm fiber forms radial loop domains.arrow_forwardA diploid human cell contains approximately 6.4 billion base pairs of DNA. Assuming that the linker DNA encompasses 35 bp, how many nucleosomes are present in such a cell? Use two significant figures. How many histone proteins are complexed with this DNA? use two significant figures.arrow_forward
- BiochemistryBiochemistryISBN:9781305577206Author:Reginald H. Garrett, Charles M. GrishamPublisher:Cengage Learning