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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3:20 minutes

Problem 74c

Textbook Question

Based on the information in Section 23.7, how would you expect each of these common metabolites to cross the cell membrane?
c. Ca²⁺

Verified step by step guidance

Understand the nature of the metabolite: Calcium ions (Ca²⁺) are charged particles, making them polar and unable to diffuse directly through the hydrophobic lipid bilayer of the cell membrane.

Recall the mechanism for charged particles crossing the membrane: Charged ions like Ca²⁺ require specific transport mechanisms, such as ion channels or transport proteins, to move across the membrane.

Identify the specific transport mechanism: Ca²⁺ typically crosses the membrane through calcium ion channels or active transport mechanisms like calcium pumps, which are proteins embedded in the membrane.

Consider the energy requirement: If the movement of Ca²⁺ is against its concentration gradient, active transport will be required, which uses energy in the form of ATP. If it moves down its concentration gradient, facilitated diffusion through ion channels may occur.

Summarize the process: Ca²⁺ crosses the cell membrane via specialized protein channels or pumps, depending on the direction of movement relative to its concentration gradient and the energy requirements.

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Key Concepts

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

Cell Membrane Structure

The cell membrane is primarily composed of a phospholipid bilayer, which creates a semi-permeable barrier. This structure allows certain molecules to pass through while restricting others based on size, charge, and polarity. Understanding this structure is crucial for predicting how different metabolites, like Ca2+, can cross the membrane.

Ion Channels and Transporters

Ions such as Ca2+ typically require specific ion channels or transporters to cross the cell membrane due to their charge and size. These proteins facilitate the movement of ions across the membrane, often in response to concentration gradients or electrical signals, which is essential for cellular functions like signaling and muscle contraction.

Active vs. Passive Transport

Transport mechanisms can be classified as active or passive. Passive transport does not require energy and occurs along concentration gradients, while active transport requires energy to move substances against their gradients. Understanding these mechanisms is vital for predicting how Ca2+ enters or exits cells, especially in processes like muscle contraction and neurotransmitter release.

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Which of the following are found in cell membranes?

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Describe other components present in a cell membrane and their relative location.

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Multiple Choice

Which one of the following components of a cell membrane extends through its entire thickness?

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Multiple Choice

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