Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 39m
3. Energy & Cell Processes10h 8m
4. Tissues & Histology10h 3m
5. Integumentary System2h 28m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System3h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

2. Cell Chemistry & Cell Components

Simple and Facilitated Diffusion

Anatomy & Physiology

2. Cell Chemistry & Cell Components

Simple and Facilitated Diffusion

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Multiple Choice

Which type(s) of molecules cannot enter/exit the cell via simple diffusion and require facilitated diffusion?

Nonpolar oxygen gas molecules.

Charged Ca²⁺ ions

Nonpolar carbon dioxide gas molecules.

Nonpolar water molecules

Charged Na⁺ ions

b and e only

a, c, and d only

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Verified step by step guidance

Understand the concept of simple diffusion: Simple diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration without the need for energy or assistance from proteins. It typically involves small, nonpolar molecules.

Identify the characteristics of molecules that use facilitated diffusion: Facilitated diffusion is used by molecules that cannot easily pass through the lipid bilayer of the cell membrane. These are usually polar or charged molecules that require the help of transport proteins.

Analyze the given molecules: Nonpolar molecules like oxygen gas (O2) and carbon dioxide (CO2) can pass through the cell membrane via simple diffusion due to their nonpolar nature. Water molecules, although polar, can also pass through the membrane to some extent due to their small size.

Focus on charged ions: Charged ions such as Ca2+ and Na+ cannot pass through the lipid bilayer via simple diffusion because the hydrophobic core of the membrane repels charged particles. These ions require facilitated diffusion, which involves specific transport proteins or channels.

Conclude which molecules require facilitated diffusion: Based on the analysis, charged ions like Ca2+ and Na+ require facilitated diffusion to enter or exit the cell, while nonpolar molecules like oxygen, carbon dioxide, and water can use simple diffusion.