Cell Membrane/Transport

permeability of lipid bilayer (4)

• nonpolar can dissolve & cross membrane

• small polar uncharged molecules get through (ex. H20, CO2, O2)

• large polar molecules will not pass (ex. glucose)

• all ions will not pass

Proteins in the membrane & where located

Integral Proteins: in or penetrates lipid bilayer

Peripheral Proteins: in cytoplasmic side of membrane

4 functions of membrane proteins

chemical transport, energy transport, transmitting messages, signal transduction

functions of cell membrane (4)

main structure, transport, fluidity, communication

5 key parts of cell membrane

bilayer, protein, cholesterol, glycoprotein, glycolipid

passive transport

movement of molecules where energy is not required

3 types of passive transport

diffusion, osmosis, facilitated diffusion

diffusion

molecules move from high to low concentration gradient

osmosis

diffusion of water across a semipermeable membrane (moves through bilayer or aquaporin)

facilitated diffusion

diffusion of solute across a membrane with help of transport proteins (helps polar & ions imbedded by lipid bilayer)

aquaporin

integral membrane proteins that channel water molecules across membrane

hypertonic

solution with higher concentration of solutes, plasmolyzed (plant loses H2O)

hypotonic

solution with lower concentration of solutes,

- turgid (plump cells)

- lyced (cell going to burst)

isotonic

equal state of concentration, flaccid (animals)

active transport

requires energy to move material across the membrane, moves from low to high concentration

example of active transport

sodium potassium pump

kinds of active transport (2)

endocytosis (phagocytosis, pinocytosis), exocytosis

endocytosis (phag, pino)

endocytosis: materials are taken into cell (large, solid)

- Phag: cell binds to and digests large particles
- Pino: cell takes in dissolved material or liquid

exocytosis

export of materials from cell

what happens to animal cells during hypertonic, isotonic, and hypotonic

shrivels, normal, lysed

what happens to plant cells during hypertonic, isotonic, and hypotonic

plasmolysed, normal, turgid

equation for water potential

solute potential + pressure potential = water potential

equation for solute potential & what does it all stand for

-iCRT

• R= 0.0831 liters bars/mole-K

• i= ionization constant

• C= molar concentration

• T= temperature in K, (273+C)