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

Cell Junctions

Anatomy & Physiology

2. Cell Chemistry & Cell Components

Cell Junctions

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Multiple Choice

Which of the following substances can pass through a gap junction?

DNA

Ions

Lipids

Proteins

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Verified step by step guidance

Understand the structure and function of gap junctions: Gap junctions are specialized intercellular connections that allow for direct communication between cells. They are composed of connexin proteins that form channels, permitting the passage of certain small molecules and ions between adjacent cells.

Identify the types of substances that can pass through gap junctions: Gap junctions typically allow the passage of small molecules and ions, such as calcium ions (Ca²⁺), potassium ions (K⁺), and other small signaling molecules. These channels are not large enough to allow the passage of larger molecules like proteins or nucleic acids.

Evaluate the size and charge of the substances listed: DNA and proteins are large macromolecules, while lipids are generally nonpolar and larger than ions. Ions, on the other hand, are small and charged, making them suitable for passage through the narrow channels of gap junctions.

Consider the physiological role of gap junctions: Gap junctions are crucial for cell-to-cell communication, particularly in tissues that require rapid and coordinated responses, such as cardiac and smooth muscle tissues. The passage of ions through gap junctions facilitates the propagation of electrical signals necessary for synchronized contraction.

Conclude which substance can pass through gap junctions: Based on the size and nature of the substances, ions are the most likely candidates to pass through gap junctions, as they are small enough to fit through the channels and are essential for cellular communication.