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

Base Pairing

Organic Chemistry

34. Nucleic Acids

Base Pairing

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Multiple Choice

Cytosine (C) makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine (T)?

16%

21%

60%

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Verified step by step guidance

Understand the base pairing rules in DNA: Cytosine (C) pairs with Guanine (G), and Adenine (A) pairs with Thymine (T). This means the percentage of C will equal the percentage of G, and the percentage of A will equal the percentage of T.

Given that Cytosine (C) makes up 42% of the nucleotides, it implies that Guanine (G) also makes up 42% of the nucleotides. Therefore, the combined percentage of C and G is 42% + 42% = 84%.

Since the total percentage of all nucleotides must equal 100%, calculate the remaining percentage for Adenine (A) and Thymine (T) by subtracting the percentage of C and G from 100%.

Perform the subtraction: 100% - 84% = 16%. This remaining percentage is shared equally between Adenine (A) and Thymine (T) because they pair together.

Conclude that the percentage of Thymine (T) in the sample is 16%, as it is half of the remaining percentage after accounting for Cytosine (C) and Guanine (G).