small membrane bound spaces in most plant and animal cells that transport macromolecules into and out of the cell and carry materials between organelles in the cell.
the mechanism that uses ATP energy to reset the sodium and potassium ions after transmission of a nerve impulse. This moves sodium and potassium against the concentration gradient.
diffusion through a channel which requires no energy.
cells shrink and shrivel in hypotonic solutions.
a form of endocytosis in which cells ingest liquids.
a form of endocytosis in which cells ingest solid matter by engulfing them like a white blood cell.
white blood cells that can engulf and destroy microorganisms including viruses and bacteria; cells in this category include neutrophils and monocytes.
8. passive transport
diffusion across a plasma membrane in which the cell expends no energy. ie. diffusion of oxygen and CO2, osmosis, and facilitated diffusion.
diffusion of water across a semi-permeable or selectively permeable membrane.
term applied to two solutions with equal solute concentrations.
types of passive transport of changed particles across the cell membrane. ie. these ions: potassium, calcium, chlorine, and sodium.
a solution having a low concentration of solute.
a solution having a high concentration of solute.
the ability to maintain a relatively constant internal environment.
widely accepted model of the plasma membrane in which proteins are embedded in the lipids.
a type of passive transport which requires the aid of carrier proteins that do not easily pass through the membrane easily. this may be caused by size or repulsion to fffffffat!
the process in which a membrane enclosed vesicle first fuses with the plasma membrane and then opens and releases it's contents to the outside.
the state in which equal concentration of a substance exists all over.
the incorporation of materials from the outside of the cell by the formation of vesicles in the plasma membrane.
the spontaneous movement of particles from an area of higher concentration to an area of lower concentration.
cell expands and bursts in a hypertonic solution.
difference of concentration across a space.
proteins in the cell membrane that aid molecules entering or leaving the cell with the concentration gradient.
requires the cell to spend energy, usually with ATP.