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

Prokaryotic & Eukaryotic Cells

Anatomy & Physiology

2. Cell Chemistry & Cell Components

Prokaryotic & Eukaryotic Cells

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1:15 minutes

Problem 14

Textbook Question

Describe the structure of the plasma membrane of an animal cell. What would be found directly inside and outside the membrane?

Verified step by step guidance

The plasma membrane, also known as the cell membrane, is primarily composed of a phospholipid bilayer. This bilayer forms the fundamental structure, with hydrophilic (water-attracting) heads facing outward and hydrophobic (water-repelling) tails facing inward.

Embedded within this phospholipid bilayer are various proteins that serve different functions. These proteins can be integral (spanning the membrane) or peripheral (attached to the surface). They play roles in transport, signaling, and maintaining the cell's structure.

Cholesterol molecules are interspersed within the phospholipid bilayer. They help to stabilize the membrane's fluidity, making it less permeable to very small water-soluble molecules that might otherwise pass freely through.

On the extracellular side of the membrane, carbohydrates are often attached to proteins and lipids, forming glycoproteins and glycolipids. These carbohydrate chains are involved in cell recognition and communication.

Directly inside the membrane, you would find the cytoplasm, which contains the cell's organelles and is the site of many metabolic processes. Outside the membrane, the extracellular matrix provides structural and biochemical support to surrounding cells.

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Key Concepts

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

Plasma Membrane Structure

The plasma membrane, also known as the cell membrane, is primarily composed of a phospholipid bilayer with embedded proteins. This bilayer forms a semi-permeable barrier that regulates the movement of substances in and out of the cell. The hydrophilic heads of phospholipids face outward towards the aqueous environments, while the hydrophobic tails face inward, creating a stable structure that is essential for cell integrity.

Fluid Mosaic Model

The fluid mosaic model describes the plasma membrane as a dynamic and flexible structure where various proteins float in or on the fluid lipid bilayer. This model emphasizes that the membrane is not static; instead, the lipids and proteins can move laterally, allowing for interactions and functions such as signaling and transport. The mosaic aspect refers to the diverse array of proteins that perform different roles, contributing to the membrane's functionality.

Extracellular and Intracellular Environments

The regions outside and inside the plasma membrane are referred to as the extracellular and intracellular environments, respectively. The extracellular space contains various substances, including nutrients, signaling molecules, and ions, which are crucial for cell communication and function. Conversely, the intracellular environment, or cytoplasm, houses organelles, enzymes, and other components necessary for cellular processes, maintaining homeostasis and supporting life.