Cell Transport and Membrane Structure
The fluid mosaic model describes the complex organization of cellular membranes and their transport mechanisms. This page covers various transport processes and the factors that influence them.
Definition: The fluid mosaic model represents the cell membrane as a fluid phospholipid bilayer containing various proteins, carbohydrates, and other molecules.
Vocabulary:
- Glycolipids: Lipids with attached carbohydrate groups
- Peripheral proteins: Proteins loosely attached to membrane surfaces
- Integral proteins: Proteins embedded within the membrane
Example: Transport mechanisms include:
- Diffusion: Movement from high to low concentration
- Facilitated diffusion: Protein-assisted transport
- Active transport: Energy-dependent movement against concentration gradients
Highlight: Key factors affecting transport rates:
- Molecule size: Smaller molecules move faster
- Temperature: Higher temperatures increase movement
- Concentration gradient: Larger differences promote faster transport
- Surface area: Greater surface area enables more transport opportunities
Quote: "Movement of water molecules from high to low concentration, over a semi-permeable membrane" - Definition of osmosis
The page also details osmotic effects on both plant and animal cells, explaining concepts like turgor pressure and plasmolysis. Active transport mechanisms, including protein pumps and ATP utilization, are thoroughly described, along with cellular processes like endocytosis and exocytosis.
