Table of contents

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

23. Lipids

Cell Membranes

GOB Chemistry

23. Lipids

Cell Membranes

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3:30 minutes

Problem 61

Textbook Question

How do molecules of cholesterol affect the structure of cell membranes?

Verified step by step guidance

Understand that cholesterol is a type of lipid molecule that is amphipathic, meaning it has both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions.

Recognize that cholesterol molecules are embedded within the phospholipid bilayer of cell membranes, where their hydrophobic regions interact with the fatty acid tails of phospholipids, and their hydrophilic hydroxyl group (-OH) aligns near the polar head groups of the phospholipids.

Learn that cholesterol plays a key role in modulating the fluidity of the cell membrane. It prevents the membrane from becoming too rigid by disrupting the close packing of phospholipid tails, especially at low temperatures.

Understand that cholesterol also prevents the membrane from becoming too fluid by stabilizing the phospholipid bilayer and reducing the movement of phospholipid molecules, particularly at high temperatures.

Conclude that cholesterol contributes to the structural integrity and dynamic nature of the cell membrane, ensuring it remains selectively permeable and functional under varying conditions.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Cholesterol Structure and Function

Cholesterol is a lipid molecule with a complex ring structure that plays a crucial role in cell membranes. It helps to maintain membrane fluidity by preventing the fatty acid chains of phospholipids from packing too closely together, which is essential for proper membrane function and flexibility.

Cell Membrane Composition

Cell membranes are primarily composed of a phospholipid bilayer, which provides a barrier to the passage of ions and molecules. The presence of cholesterol within this bilayer influences its physical properties, such as fluidity and permeability, thereby affecting how cells interact with their environment.

Membrane Fluidity

Membrane fluidity refers to the viscosity of the lipid bilayer of a cell membrane, which is crucial for the movement of proteins and lipids within the membrane. Cholesterol modulates this fluidity, allowing membranes to remain flexible across varying temperatures, which is vital for cellular processes like signaling and transport.