Cell Membrane Flashcards
Cell Membrane
the cell membrane encloses the contents of the cell. It is semi-permeable and has a fluid mosaic model.
Semi-Permeable
allows some molecules to pass through, but not others
Fluid Mosaic Model
the membrane has a lipid bilayer with associated protein, carbohydrate and cholesterol molecules.
Protein Molecule (Cell Membrane)
found in the membrane and act as channel for specific substances to cross the membrane or as receptors for the cell to respond to its environment.
Phospholipids
major membrane lipids that consist of lipid bilayers, whose arrangement regulates movement in and out of the cell. Only permeable to lipid soluble material
Cholesterol Molecule
assist with the fluidity of the membrane
Carbohydrates (Cell Membrane)
attached to molecules on the outer surface and act as markers for communication and identification
Lipid Bilayer
2 layers of phospholipid molecules.
Extracellular
outside the cell
Intracellular
inside the cell
Osmosis
the movement of water from a low solute concentration to a high solute concentration.
Simple Diffusion
the movement of small, nonpolar molecules directly through the lipid bilayer without the help of proteins
Facilitated Diffusion
the movement of larger or charged molecules across the membrane with the help of transport proteins
Endocytosis
moves material into a cell and has two types: phagocytosis and pinocytosis
Exocytosis
moves material out of a cell via vesicles. e.g. hormones, mucus and digestive enzymes move from where they are made to extracellular fluid.
What does a Difference in Concentration of Molecules Cause
this leads to particles moving without energy from high concentration to low due to higher collisions of particles in the highly concentrated area causing them to spread out.
Solution Concentration
there are 3 types of solution concentration: isotonic, hypotonic, hypertonic.
Isotonic Concentration
when solute concentration is equal inside and outside a cell.
Hypotonic Concentration
when the cell has a higher solute concentration than that surrounding it causing water to enter to cell which can lead to it bursting.
Hypertonic Concentration
when the liquid surrounding the cell has a higher solute concentration than inside the cell, causing water to move out of the cell and shrink.
Passive Transport
movement of molecules across the cell membrane without the use of energy. Substances move with the concentration gradient from high to low.
Active Transport
movement of molecules across a cell membrane with the use of energy. Substances move against the concentration gradient from low to high.
Phagocytos
the transport of solid particles into a cell.
Pincytosis
the transport of liquids into a cell
