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

32. Lipids

Intro to Lipids

Organic Chemistry

32. Lipids

Intro to Lipids

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Multiple Choice

Which statement best describes how cholesterol affects cell membrane fluidity?

Cholesterol uniformly increases membrane fluidity regardless of temperature.

Cholesterol uniformly decreases membrane fluidity regardless of temperature.

Cholesterol increases membrane fluidity at high temperatures and decreases it at low temperatures.

Cholesterol decreases membrane fluidity at high temperatures and increases it at low temperatures.

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Verified step by step guidance

Understand the role of cholesterol in cell membranes: Cholesterol is a lipid molecule that is interspersed within the phospholipid bilayer of cell membranes. It plays a crucial role in modulating membrane fluidity.

Consider the effect of temperature on membrane fluidity: At high temperatures, phospholipid bilayers become more fluid as the kinetic energy of the molecules increases. Cholesterol helps stabilize the membrane by reducing fluidity, preventing it from becoming too permeable.

Analyze the effect of cholesterol at low temperatures: At low temperatures, the phospholipid bilayer becomes more rigid and less fluid. Cholesterol disrupts the regular packing of phospholipids, increasing fluidity and preventing the membrane from becoming too rigid.

Recognize the dual role of cholesterol: Cholesterol acts as a buffer for membrane fluidity, increasing fluidity at low temperatures and decreasing it at high temperatures, thus maintaining optimal membrane function across temperature variations.

Conclude with the correct statement: Cholesterol decreases membrane fluidity at high temperatures and increases it at low temperatures, ensuring the cell membrane remains functional under varying thermal conditions.