Cell/Plasma Membrane (passive)
Membrane that helps maintain homeostasis by controlling what substances enter and leave the cell. A form of passive transport.
Simplest type of passive transport. It's the movement of molecules from an area of high concentration to low concentration.
Concentration Gradient (passive)
The difference in concentration of molecules across a space.
Kinetic energy that molecules possess
What is diffusion driven by?
From high conc. to low conc.
How do molecules move "down" their concentration gradients?
A state when the concentration of molecules of a substance is same throughout a space.
Process by which H2o molecules diffuse across cell membrane from an area of high conc. to low conc. Form of passive transport.
Conc. of solute molecules outside cell is higher than conc. inside cell. (shrink, shrivel)
Conc. of solutes outside and inside cell are equal (same)
Conc. of solute molecules outside cell is lower than inside. (going to blow)
Organelles that remove excess H2o and pump it out of the cell.
Unicellular freshwater organisms like paramecium
In what organisms are contractile vacuoles found?
Turgor Pressure (passive)
Pressure that H2o molecules exert against cell walls since most of the time plants live in hypotonic environments.
Hypertonic in plants. It's why plants wilt when not watered.
Hypotonic, causing cell to burst.
Facilitated Diffusion (passive)
Can not diffuse molecules rapidly through cell membrane because molecules may not be soluble or too large to pass through pores. Uses carrier proteins (does not use energy)
Diffusion through ion channels (passive)
Ions are not soluble in lipids therefore do not diffuse with out assistance.
A complex of protein molecules in a cell membrane that forms a pore through which ions can pass.
The movement of a substance across cell membrane without use of energy
A thin membrane made of two layers of lipid molecules. These membranes are flat sheets.
Materials move up their conc. gradient from lower conc. to higher conc. Requires energy!
Membrane Pumps (active)
Carrier protein that uses energy to push molecules across conc. gradient from low to high.
Sodium Potassium Pump (active)
Transports Na+ and K+ up their conc. gradients
Many animal cells
What kind of cells has higher conc. of Na+ ions outside the cell and higher conc. of K+ ions inside the cell?
How many Na+ ions bind to carrier proteins in cytosol and transport to outside?
Carrier proteins split phosphate groups from what (used for energy)?
How many K+ ions bind to carrier proteins on outside and transports to cytosol?
Process which cells ingest fluid, macromolecules, large particles.
Pouch on surface of plasma membrane that "pinches" particles and brings them into the cell (endocytosis)
Cell drinking (endocytosis)
Cell eating (endocytosis)
Vesicles reverse the endocytosis process and force the material out of the cell.
Outside membrane is positive charged and inside membrane is negative charged.
Allows lysosomes to fuse with vesicles that contains ingested bacteria and viruses. Lysosomal enzymes destroy bacteria and viruses before it can harm the animal.
Shields molecules from interior of lipid bilayer.
Helps rid itself of wastes
Gated Ion Channels
May be open or closed according to selectivity of membrane.
What can pass through cell membranes by diffusion?
What does the process of endocytosis and exocytosis require?
Organelle that pumps water out of the cell.
When a human red blood cell is placed in a hypotonic environment, what will happen to the cell?