Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

34. Nucleic Acids

DNA Double Helix

Organic Chemistry

34. Nucleic Acids

DNA Double Helix

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Multiple Choice

One turn of a DNA sequence is comprised of 15% adenine (A). If the bonding energies of A–T and G–C are 24 kJ/mol and 18 kJ/mol respectively, calculate the approximate total bonding energy in this one turn.

110 kJ/mol

432 kJ/mol

222 kJ/mol

198 kJ/mol

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Verified step by step guidance

Understand that in DNA, adenine (A) pairs with thymine (T) and guanine (G) pairs with cytosine (C). The percentage of adenine will equal the percentage of thymine, and the percentage of guanine will equal the percentage of cytosine.

Since adenine (A) makes up 15% of the sequence, thymine (T) will also make up 15%. Therefore, the total percentage of A-T pairs is 30%.

The remaining percentage of the DNA sequence will be composed of G-C pairs. Since A-T pairs make up 30%, G-C pairs will make up 70% of the sequence.

Calculate the contribution of A-T pairs to the total bonding energy by multiplying the percentage of A-T pairs (30%) by the bonding energy of an A-T pair (24 kJ/mol).

Calculate the contribution of G-C pairs to the total bonding energy by multiplying the percentage of G-C pairs (70%) by the bonding energy of a G-C pair (18 kJ/mol). Add the contributions from both A-T and G-C pairs to find the total bonding energy for one turn of the DNA sequence.