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

Why doesn't penicillin work on all bacteria?

Penicillin is ineffective against bacteria that produce excess lipopolysaccharides.

Penicillin is only effective against bacteria that lack a cell membrane.

Penicillin is only effective against gram-positive bacteria due to their cell wall structure.

Penicillin targets bacterial DNA, which is not present in all bacteria.

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Verified step by step guidance

Understand the structure of bacterial cells: Bacteria are classified into two main types based on their cell wall structure: gram-positive and gram-negative. Gram-positive bacteria have a thick peptidoglycan layer, while gram-negative bacteria have a thinner peptidoglycan layer and an outer membrane containing lipopolysaccharides.

Recognize the mechanism of action of penicillin: Penicillin works by inhibiting the synthesis of peptidoglycan, an essential component of the bacterial cell wall. This inhibition weakens the cell wall, leading to cell lysis and death, particularly in gram-positive bacteria.

Identify why penicillin is ineffective against gram-negative bacteria: The outer membrane of gram-negative bacteria acts as a barrier, preventing penicillin from reaching the peptidoglycan layer effectively. Additionally, gram-negative bacteria may produce beta-lactamase enzymes that degrade penicillin.

Clarify the misconception about cell membranes: All bacteria have cell membranes, but penicillin's effectiveness is related to the cell wall structure, not the presence or absence of a cell membrane.

Summarize the key point: Penicillin is primarily effective against gram-positive bacteria due to their exposed peptidoglycan layer, which is the target of penicillin's action. Gram-negative bacteria's outer membrane and potential enzyme production make them resistant to penicillin.