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

3. Acids and Bases

Organic Chemistry Reactions

Organic Chemistry

3. Acids and Bases

Organic Chemistry Reactions

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Multiple Choice

Which of the following conditions leads to maximal expression of the lac operon?

Low glucose, low lactose

Low glucose, high lactose

High glucose, high lactose

High glucose, low lactose

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Verified step by step guidance

Understand the role of the lac operon: It is a set of genes responsible for the metabolism of lactose in bacteria, primarily E. coli. The operon is regulated by the presence or absence of glucose and lactose.

Identify the regulatory mechanisms: The lac operon is controlled by two main factors: the presence of lactose and the absence of glucose. Lactose acts as an inducer by binding to the repressor and preventing it from blocking the operon. Low glucose levels lead to high cyclic AMP (cAMP) levels, which activate the catabolite activator protein (CAP) to enhance transcription.

Analyze the given conditions: For maximal expression of the lac operon, lactose must be present to inactivate the repressor, and glucose must be absent to allow cAMP-CAP complex formation, which enhances transcription.

Evaluate each condition: Low glucose, low lactose will not lead to maximal expression because lactose is needed to inactivate the repressor. High glucose, high lactose will not lead to maximal expression because high glucose levels prevent cAMP-CAP complex formation. High glucose, low lactose will not lead to maximal expression for both reasons.

Conclude with the correct condition: Low glucose, high lactose is the condition that leads to maximal expression of the lac operon, as it allows for both the inactivation of the repressor by lactose and the activation of transcription by the cAMP-CAP complex.