The Cell Membrane -The cell membrane's purpose is to protect the cell interior. Selective permeable enable the membrane to do that so strictly allow select types of molecules can physically go through the cell membrane. The membrane is amphipathic so it has both hydrophilic and phobic areas.  The Membrane Consists of:
The bilayer is what cause the cell membrane to be amphipathic because the phospholipids has a hydrophilic and hydrophobic side. Cholesterol It is large and sturdy molecule the helps make the lipid bilayer with membrane stabilization. 25% of cholesterol is in animal cells Integral Proteins It is a trans-membrane protein that permanently attached to the biological membrane Peripheral Proteins By attaching to the inside and outside the heads of the lipids, it helps with communication and molecular recognition. Membrane Carbohydrate Helps marker the cells for recognition Transport Homeostasis: When you body and cells try to keep condition's in balance. In order to achieve homeostasis your body use transports to help balance it. Some of the transport require no energy at all as to where others do. Passive Transport Transport the require no use of energy, in order to achieve homeostasis.  Diffusion Molecules spreading out into available space, requiring the cell membrane to open the protein channels in order for it to occur. The diffusion of water, when water molecule are used to dissolve a solute to diffuse. Osmosis The diffusion of water across a selectively permeable membrane  Facilitated Diffusion  This is special kind of diffusion for large hydrophilic molecules such as salt, sugar, etc Sugar is a hard molecule to get through a regular protein channel so it has a carrier protein to help it get through. Ion Channel For ions there are specific channels for each ion to pass through into the cell membrane  Water Balance Osmoregulation -the maintenance of the water balance in concentrations Hypertonic - When solution has a higher concentration than the cell causing the cell to shrink Hypotonic - The solution has lover concentration than cell, the cell expands. Isotonic - The concentration in the solution and cell are balanced, no change is occurring Active Transport The cell membrane forcing molecules to move again their concentration gradient which is normal up the gradient. This requires ATP energy and therefore unbalancing homeostasis. Sodium-Potassium Pump  A fancy Integral protein that uses ATP to pump sodium and potassium. Every 3 sodium ion pumped out, 2 potassium ion will pumped in.  Exocytosis and Endocytosis Exocytosis - secretion of macromolecules by the fusion of vesicles with the plasma memb plasma membrane.raneEndocytosis - the import of macromolecules by forming vesicles with Phagocytosis - the cell consumes the large molecules Pinocytosis - the cell that consumes the small molecules |
Class Notes > Cells and Reproduction >
