When a double-stranded DNA molecule is exposed tohigh temperature, the two strands separate, and themolecule loses its helical form. We say the DNA hasbeen denatured. (Denaturation also occurs whenDNA is exposed to acid or alkaline solutions.)a. Regions of the DNA that contain many A–T basepairs are the first to become denatured as the temperature of a DNA solution is raised. Thinkingabout the chemical structure of the DNA molecule, why do you think the A–T-rich regionsdenature first?b. If the temperature is lowered, the original DNAstrands can reanneal, or renature. In addition to thefull double-stranded molecules, some molecules ofthe type shown here are seen when the moleculesare examined under the electron microscope. Howcan you explain these structures?

When a double-stranded DNA molecule is exposed tohigh temperature, the two strands separate, and themolecule loses its helical form. We say the DNA hasbeen denatured. (Denaturation also occurs whenDNA is exposed to acid or alkaline solutions.)a. Regions of the DNA that contain many A–T basepairs are the first to become denatured as the temperature of a DNA solution is raised. Thinkingabout the chemical structure of the DNA molecule, why do you think the A–T-rich regionsdenature first?b. If the temperature is lowered, the original DNAstrands can reanneal, or renature. In addition to thefull double-stranded molecules, some molecules ofthe type shown here are seen when the moleculesare examined under the electron microscope. Howcan you explain these structures?

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter8: The Structure, Replication, And Chromosomal Organization Of Dna

Section: Chapter Questions

Problem 12QP: DNA contains many hydrogen bonds. Are hydrogen bonds stronger or weaker than covalent bonds? What...

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In a melting profile for DNA, the absorbance at 260 nm increases as result of the disruption of the DNA structure. What is the fundamental physical basis for the absorbance increase? a. the effective concentration of DNA changes b. the absorbance of DNA is highly sensitive to temperature c. native DNA absorbs light more strongly than denatured DNA because the bases are stacked d. denatured DNA absorbs light more strongly than native DNA because the bases have become unstacked
The Bacteria Escherichia coli DNA genome has a molecular mass of about 3.1 X 109 In your answers, show how you came up to each result? (a) How many base pairs does this bacterium contain? (b) How many full double-helical turns does this DNA contain? (c) How long is this DNA in mm?
The Bacteria Escherichia coli DNA genome has a molecular mass of about 3.1 X 10 9 D. In your answers, show how you came up to each result?(a) How many base pairs does this bacterium contain? (b) How many full double-helical turns does this DNA contain? (c) How long is this DNA in micrometer?
DNA solution is viscous because of the nature of chemical substance that can intercalate into the DNA helix. An example of such substance is acridine orange. experiments revealed that acridine orange causes an increase in the viscosity of DNA solution.how would you account for this effect?
Draw the structure of deoxyribose and number the carbon atoms.Describe the numbering of the carbon atoms in deoxyribose withregard to the directionality of a DNA strand. In a DNA doublehelix, what does the term antiparallel mean?
Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes? Group of answer choices A. All bases would be separated from the deoxyribose sugars B. The purines would be separated from the deoxyribose sugars C. The phosphodiester linkages between deoxyribose sugars would be broken D. The two strands of the double helix would separate E. The pyrimidines would be separated from the deoxyribose sugars
You perform an experiment to determine the complete melting profile of a relatively long DNA duplex with 80% G:C base pairs. Sketch a graph of Absorbance at 260 nm (Y-axis) vs. Temperature (X-axis). Label the location of the Tm and describe what is happening to the DNA structure in each segment of the graph (lower Temps, highest Temps, at Tm).
A student has drawn an enlarged portion of a DNA “ladder” model to show two of the nucleotides in greater detail (in the same orientation as they would occur in the ladder model). Which two nucleotides did the student draw?
A plot showing the % of denaturation as a function of temperature for a melting point of a DNA sample under 0.12 M NaCl gives an equation of a line of Y= 0.0074 X - 0.044. (where Y is the % of denaturation and X is the temperature in °C) Question: Calculate the melting point of this DNA in °C.
A plot showing the % of denautration as a function of temperature for a melting point of a DNA sample under 0.12 M NaCl gives an equation of a line of Y= 0.0074 X - 0.044 (Where Y is the % of denautration and X is the temperature in degree C) This is all the information that was given. 1. Calcuate the melting point of this DNA in degree C
In Noll’s experiment to test the beads-on-a-string model, exposure of nuclei to a low concentration of DNase I resulted ina. a single band of DNA with a size of approximately 200 bp.b. several bands of DNA in multiples of 200 bp.c. a single band of DNA with a size of 100 bp.d. several bands of DNA in multiples of 100 bp
With regard to Chargaff’s experiment described in Figure shown,answer the following:A. What is the purpose of paper chromatography?B. Explain why it is necessary to remove the bases in order todetermine the base composition of DNA.C. Would Chargaff’s experiments have been convincing if theyhad been done on DNA from only one species? Discuss.