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 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 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

Passive vs. Active Transport

Anatomy & Physiology

2. Cell Chemistry & Cell Components

Passive vs. Active Transport

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2:31 minutes

Problem 14

Textbook Question

By what three major transport mechanisms do substances get into and out of cells?

Verified step by step guidance

Understand that substances move into and out of cells through three major transport mechanisms: passive transport, active transport, and vesicular transport. Each mechanism has distinct characteristics and energy requirements.

Passive transport does not require energy and relies on the concentration gradient. Examples include diffusion, facilitated diffusion, and osmosis. Diffusion involves the movement of molecules from an area of higher concentration to lower concentration, while facilitated diffusion uses protein channels or carriers to assist larger or charged molecules.

Active transport requires energy in the form of ATP to move substances against their concentration gradient (from lower to higher concentration). Examples include the sodium-potassium pump, which maintains ion gradients essential for cell function.

Vesicular transport involves the movement of larger molecules or particles via vesicles. This includes endocytosis (bringing substances into the cell) and exocytosis (expelling substances out of the cell). Subtypes of endocytosis include phagocytosis (cell eating) and pinocytosis (cell drinking).

Review the differences between these mechanisms, focusing on energy requirements, direction of movement relative to the concentration gradient, and the types of substances transported. This will help you understand how cells maintain homeostasis and interact with their environment.

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Key Concepts

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

Diffusion

Diffusion is the passive movement of molecules from an area of higher concentration to an area of lower concentration. This process does not require energy and occurs until equilibrium is reached. It is essential for the transport of small, nonpolar molecules, such as oxygen and carbon dioxide, across the cell membrane.

Active Transport

Active transport is the process by which cells move substances against their concentration gradient, from areas of lower concentration to areas of higher concentration. This mechanism requires energy, usually in the form of ATP, to function. It is crucial for maintaining cellular homeostasis and transporting ions and larger molecules that cannot passively diffuse through the membrane.

Facilitated Diffusion

Facilitated diffusion is a type of passive transport that utilizes specific transport proteins to help move substances across the cell membrane. This process is essential for the transport of larger or polar molecules, such as glucose and ions, which cannot easily pass through the lipid bilayer. It allows cells to efficiently uptake necessary nutrients without expending energy.

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