Active or passive

Against or Against

Concentration or Concentration

Gradient or Gradient

• use bilayer, proteins or vesicles

Simple Diffusion

1. when substances move from a high concentration to a low concentration till net movement is zero/equilibrium is reached

   • substances are lipid soluble - ex. fatty acids, O2, CO2 + alcohols

2. Osmosis

   • diffusion of H2O only

   • wattle move from high concentration to low concentration (with the concentration gradient)

   • osmotic pressure is generated by substances dissolving in water

   • Water moves from a low osmotic pressure to a high osmotic pressure

Facilitated Transport

• requires the use of proteins

• substances move from high concentration to low concentration (with concentration gradient)

1. Facilitated diffusion using chanel proteins

   • small water soluble substances - ex. Na+, Cl-

   • move through chanel proteins (usually open)

2. Facilitated diffusion using carrier proteins

   • substances move from high to low concentration

   • large water soluble substance

   • ex. glucose

   • each molecule has it own type of carrier protein because the binding site must have a complementary shape to move the molecule

   • carrier protein changes shape to move the molecule

3. Active transport

   • Substances move from low to high concentration or against the concentration gradient

   • energy is required

   • large water soluble - ex. glucose

Vesicular Transport

• use vesicles (Golgi or membrane)

• always active

• bulk substances in/out

1. Endocytosis

   • cell membrane wrap around sub until it encloses them in a vesicle (made from bilayer) and its in the cytoplasm

   • pinocytosis (liquid)

   • phagocytosis (solid)

2. Exocytosis

   • substances within the cell are packaged into a vesicle by the Golgi body

   • it migrates to be dumped outside the cell