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 30% guanine (G). Calculate the approximate number of hydrogens bonds likely to be found within this DNA sequence.

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Verified step by step guidance

Understand that DNA is composed of two strands forming a double helix, where the bases pair with each other: adenine (A) pairs with thymine (T) and guanine (G) pairs with cytosine (C).

Recognize that guanine (G) and cytosine (C) pair through three hydrogen bonds, while adenine (A) and thymine (T) pair through two hydrogen bonds.

Calculate the percentage of cytosine (C) in the DNA sequence. Since guanine (G) makes up 30% of the sequence, cytosine (C) will also make up 30% due to base pairing rules.

Determine the percentage of adenine (A) and thymine (T) in the sequence. Since G and C together make up 60% of the sequence, A and T will make up the remaining 40%, with each contributing 20%.

Calculate the total number of hydrogen bonds: multiply the percentage of G-C pairs by 3 (for three hydrogen bonds per pair) and the percentage of A-T pairs by 2 (for two hydrogen bonds per pair), then sum these values to find the total number of hydrogen bonds in the sequence.