Questions and Answers
What is the main feature of the cell membrane that prevents visibility under a light microscope?
What structure is observed at higher magnification using an electron microscope?
Which of the following components is NOT typically a part of the cell membrane?
What role do the hydrophobic tails of phospholipids play in the cell membrane structure?
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What is the total thickness of the cell membrane as observed under low magnification with an electron microscope?
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Study Notes
Introduction to Cell Membrane
- The cell is the basic unit of structure and function in the body.
- Similar cells group together to form tissues.
- Tissues combine to create organs.
- Organs work together in body systems.
Cell Membrane Overview
- Also referred to as the plasma membrane or plasmalemma.
Viewing the Cell Membrane
-
Light Microscope (LM):
- Cell membrane is not visible due to thinness; staining reveals its presence.
-
Electron Microscope (EM):
- Low Magnification: Displays a thin, dense line measuring 8 - 10 nm.
-
Higher Magnification: Shows a trilaminar structure with:
- Two electron-dense lines (outer and inner leaflets).
- A middle electron-lucent zone.
- Collectively referred to as the unit membrane.
Molecular Structure of the Cell Membrane
- Composed of key components:
- Lipid Molecules: Include phospholipids and cholesterol.
- Protein Molecules
- Carbohydrate Molecules
- The structure is consistent across cell membranes and membranous organelles, with slight variations.
Lipid Molecules
Phospholipids
- Each phospholipid has:
- Polar Hydrophilic Head: Faces the aqueous environments outside and inside the cell.
- Two Non-polar Hydrophobic Tails: Fatty acids that extend toward each other in the membrane's center, forming a bilayer through weak non-covalent bonds.
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Description
Explore the structure and function of the cell membrane in this quiz. Understand how cells organize into tissues, organs, and body systems while focusing on the plasma membrane's characteristics. Test your knowledge on microscopic viewing techniques and their limitations.
