Structure And Function Of Plasma Membrane Flashcards
The function of the cell membrane is…
The boundary that separates the living cell from the non-living surroundings
The plasma membrane controls…
Which substances pass in and out of the cell
Uptake of nutrients
Secreting enzymes and glycoproteins
Cell recognition
Fluid mosaic model meaning
Fluid- phospholipids can drift, not locked in place
Mosaic- proteins, cholesterol and carbohydrates are embedded into the membrane
Protein that are on the surface of bilayer to provide structural support
Extrinsic
Proteins that go through the bilayer to act as channels and carries and pumps
Integral
Cholesterol function
Increases rigidity and stability
Glycolipid function
Found on outer layer and involved in cell recognition
What molecules can freely pass via simple diffusion?
Small, non-polar molecules
Lipid soluble
What do large, charged molecules require to pass?
Integral proteins for facilitated diffusion and active transport
Movement of molecules/ions from a region of high conc to a region of low conc until equally distributed?
ATP?
Diffusion
NO
What does facilitated diffusion require?
Carrier protein that rotates and changed shape to drop molecule on other side
Concentration gradient
The movement of molecules of H2O from a region of high water potential to a region of low water potential via a semi-permeable membrane.
Osmosis
Lower water potential inside the cell so H2O moves out
HYPERTONIC
Same water potential so no net movement
ISOTONIC
Higher water potential outside the cell so H2O moves in
HYPOTONIC
ATP is required when molecules are moved….
Against a concentration gradient
Active transport requires a specific
Intristic protein pump
Uses a gradient generated by primary active transport to enhance the movement of a second substance?
Secondary active transport
Uniporter
One channel
Symporter
Two channels, same direction
Antiporter
Two channels, opposite directions
Cell engulfs debris, bacteria or other sizzle objects within specialised cells
Phagocytosis
Cell engulfs extracellular fluid and enters cell via a vesicles but does not mix with the cytoplasm
Pincytosis
Allows cells to take up specific macromolecules called ligands. Requires specific membrane receptors
Receptor-mediated endocytosis
Release of material from the call by changing the cell membrane.
Exocytosis
