Processes Questions and Answers
Selectively Permeable Plasma Membrane - ✅✅some molecules pass through easily, others do not
Diffusion - ✅✅movement of molecules sown their concentration gradients (from high to low); energy
is not required; speed of diffusion is influenced by size of molecule and temperature; molecules have a
natural drive to diffuse down concentration gradients that exist between extracellular and intracellular
areas;
Concentration Gradient - ✅✅Collisions between molecules in areas of high concentration cause them
to be scattered into areas with less concentration, the difference is called the concentration gradient.
What are the two main types of transport? - ✅✅Passive and active transport
Passive Transport - ✅✅No ATP (or energy) needed; substances move down their concentration
gradient (from high to low); 4 different types
What are the 4 types of Passive Transport? - ✅✅Simple diffusion, facilitated diffusion, osmosis, and
bulk flow
Simple Diffusion - ✅✅Substances pass through lipid bilayer: ex. lipid soluble molecules, small
molecules, oxygen, CO2 and lipid soluble vitamins;
Facilitated Diffusion - ✅✅substances move across membrane by protein channel sor carrier proteins
such as glucose, amino acids, and ions; carrier proteins are substance specific; ions mostly through
channels
Osmosis - ✅✅water moving through semi-permeable membrane; in the case where water freely
moves by osmosis but membrane relatively impermeable to solutes, the cell will take in or lose water
depending on concentration of extracellular fluid relative to intracellular fluid; water always moves to
the hypertonic