Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
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 Heart2h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 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 of the following would be least likely to diffuse through a plasma membrane without the help of a transport protein?

A large, nonpolar molecule

Dissolved gases such as oxygen or carbon dioxide

A small, nonpolar molecule

Any of the listed molecules would easily diffuse through the membrane.

A large, polar molecule

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Verified step by step guidance

Understand the structure of the plasma membrane: The plasma membrane is primarily composed of a phospholipid bilayer, which has hydrophobic (water-repelling) tails and hydrophilic (water-attracting) heads. This structure allows nonpolar molecules to pass through easily, while polar molecules face resistance.

Identify the properties of molecules that affect diffusion: Nonpolar molecules can easily pass through the hydrophobic core of the membrane, while polar molecules require assistance due to their affinity for water and the hydrophobic nature of the membrane interior.

Consider the size of the molecule: Smaller molecules can diffuse more easily through the membrane than larger ones, as they can navigate through the spaces between the phospholipids more readily.

Evaluate the options given: Dissolved gases like oxygen and carbon dioxide are small and nonpolar, allowing them to diffuse easily. Small, nonpolar molecules also pass through without difficulty. Large, nonpolar molecules can still diffuse, albeit more slowly than smaller ones.

Conclude which molecule is least likely to diffuse without assistance: A large, polar molecule would face significant resistance due to both its size and polarity, making it least likely to diffuse through the plasma membrane without a transport protein.