Consider normal B-form DNA. It forms a regular antiparallel double-helical structure with Watson-Crick base-pairing mediated through hydrogen bonding. The base pairs all stack upon one another, with 3.4 Å spacing between them. DNA strands having a complementary sequence will spontaneously form a double-helix in an aqueous solution. In terms of energy, what primarily drives helix formation?

Consider normal B-form DNA. It forms a regular antiparallel double-helical structure with Watson-Crick base-pairing mediated through hydrogen bonding. The base pairs all stack upon one another, with 3.4 Å spacing between them. DNA strands having a complementary sequence will spontaneously form a double-helix in an aqueous solution. In terms of energy, what primarily drives helix formation?

Anatomy & Physiology

1st Edition

ISBN:9781938168130

Author:Kelly A. Young, James A. Wise, Peter DeSaix, Dean H. Kruse, Brandon Poe, Eddie Johnson, Jody E. Johnson, Oksana Korol, J. Gordon Betts, Mark Womble

Publisher:Kelly A. Young, James A. Wise, Peter DeSaix, Dean H. Kruse, Brandon Poe, Eddie Johnson, Jody E. Johnson, Oksana Korol, J. Gordon Betts, Mark Womble

Chapter2: The Chemical Level Of Organization

Section: Chapter Questions

Problem 30RQ: In DNA, nucleotide bonding forms a compound with a characteristic shape known as a(n) ________. beta...

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Proflavine was used to treat wounded soldiers in the Far East during the second world war. Which of the following statements is false regarding proflavine! H₂N7 NH₂ Its target is located in the cell membrane. Its planar shape is important to intercalation. The primary amine groups are protonated and interact with phosphate groups of the DNA backbone. When inserted into DNA, the tricyclic system can form van der Waals interactions with base pairs above and below it.
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CAN YOU PLEASE ANSWER 1b 1a) The phosphate groups in the sugar-phosphate backbone of each strand of a DNA molecule have a pKa of ~2.14. Normal physiological pH in most cells is 7.0-7.5, which is significantly above the pKa for the phosphate groups, so every phosphate group in the backbone of both strands of a DNA molecule is deprotonated and carries a -1 charge - but DNA in cells is normally double-stranded. Briefly explain, in your own words, why the large negative charges on the backbones of the two strands of a double-stranded DNA molecule don't cause the strands to separate under normal cellular conditions. 1b) If you raise the pH to 12, but keep everything else about the solution in which the double-stranded DNA is dissolved the same, the two strands of DNA will separate/the DNA will denature. Briefly explain, in your own words, why this happens - why does DNA denature at pH 12 but not at pH 7?
It is known that double stranded DNA is denatured at low pH. pKa values should allow the determination of whether this is due to perturbation of the hydrogen bonding in A-T and/or G-C base pairs. The table gives values for the pKas of different protonated groups in the nucleobases.Nucleobase Position & pKa A N1, 3.5 G N7, 1.6; N1, 9.2 C N3, 4.2 T N3, 9.7a) Draw the A-T and G-C base pairs. - Label the bases with the one-letter code. – - Number the atoms in the rings and label the atom that attaches to the sugar. - Mark the groups that interact in normal…