Questions and Answers
What is the other name for the plasma membrane?
Cell membrane
What is the function of the plasma membrane?
It regulates what enters and exits the cell.
Why is it important that the plasma membrane regulates what enters and leaves the cell?
Because it helps the cell and the organism maintain a steady internal environment.
What is the key structure of the plasma membrane?
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Is the head of the phospholipid hydrophilic or phobic?
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Is the tail of the phospholipid hydrophilic or phobic?
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Is the head of a phospholipid polar or non-polar?
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What are phospholipids?
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Is the phospholipid tail polar or non-polar?
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What does the phospholipid head consist of?
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What does the phospholipid tail consist of?
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What is the phospholipid wall called?
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What is one of the proteins in the phospholipid bilayer called?
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How is glucose passed through the plasma membrane?
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What is glucose helped by to cross the membrane?
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Can starch and proteins pass the plasma membrane easily and why?
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What has to be broken down to go through the plasma membrane?
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What can pass easily through the plasma membrane and why?
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What is endocytosis?
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What are the solid particles when the cell engulfs large particles?
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What are the liquid particles when the cell engulfs the particles?
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What is exocytosis?
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Study Notes
Plasma Membrane Overview
- Also known as the cell membrane, it serves as a boundary for cells, determining the movement of substances in and out.
- Regulates entry and exit of materials, maintaining a steady internal environment for the cell and organism (homeostasis).
Structural Composition
- Composed primarily of phospholipids and proteins.
- Phospholipids have a hydrophilic (water-loving) head and two hydrophobic (water-fearing) fatty acid tails.
- The phospholipid arrangement forms a bilayer, providing fluidity and flexibility to the membrane.
Properties of Phospholipids
- The head of a phospholipid is polar, allowing it to interact with water.
- The tails of phospholipids are non-polar, making them repellent to water.
- The head consists of a phosphate group (PO4), while the tail consists of two fatty acid chains.
Protein Functions
- Proteins embedded in the bilayer include channel proteins, which assist in the transport of larger molecules such as glucose.
- Glucose, being larger, requires proteins to pass through the membrane rather than diffusing freely.
Transport Mechanisms
- Small molecules like H2O, CO2, and O2 can easily traverse the membrane due to their size.
- Larger molecules like starch and proteins cannot pass easily; they require breakdown for movement through the membrane.
Cellular Processes
- Endocytosis allows cells to engulf large particles by folding the membrane around them to form intracellular vesicles.
- Phagocytosis is the process of engulfing solid particles, while pinocytosis refers to the engulfing of liquids.
- Exocytosis is the reverse process, where substances like hormones and enzymes are released from the cell.
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Test your knowledge about the plasma membrane with these informative flashcards. Learn about its other names, functions, and importance in maintaining cellular homeostasis. Perfect for biology students looking to reinforce key concepts.
