the model that gives a good idea about properties of the Plama Membrane

-Fluid- not stiff, always moving, never the same one second as the next

Mosiac- made of many things-not just phospholipids- has proteins, cholesterol, carbohydrates, 

• 2 an inner leaflet and an outer leaflet

• long tails of carbon and hydrogens with a phosphate head
• the heads are polar, and the tails are non-polar and hydrophobic

a molecule with different properties at wither ends

ex; phospholipid

1. Peripheral Proteins
2. Integral Proteins
3. Transmembrane

proteins embedded in the lipid layer

• they have long regions that are hydrophobic that can interact with those lipid tails

• as transport protein
• some enzymes sit in the membrane to catalyze their reactions
• signaling proteins allow the cell to communicate with their external environment
• some proteins are in places where cells will directly message one another without signaling molecules
• serve as anchorage points between two cells so they stick together

passive transport

active transport

the movement of molecules across the membrane without the use of energy

• driven by natural properties of molecules- they need space

the movement of molecules from high concentration to low concentration- they go down the concentration gradient

• molecules keep moving till things are evenly spaced- not even in number
• wants homeostasis
• things hit each other and then spread out due to ricochetted
• happens spontaneously

equality, and the net movement of zero

what cells want mostly

only allows some things across the cell membrane

• so even id the concentration gradient may build up- molecules cannot diffuse across the membrane to equal it out

• very small, nonpolar molecules and lipid- soluble molecules

water-soluble substances( slats, amino acids, sugars) and large molecules

• They need the help of transport proteins, sometimes a channel

what is facilitated diffusion

• the molecule passes itself or passes through a channel/pore protein
• since the molecule isnt doing anything other than just sitting there so the diffusion carrying the molecule is still passive

the movement of water across a semi-permeable membrane to compensate for a concentration gradient

- so if the molecules cant move across the membrane, the water will- the water is moving to the more concentrated solute area

the ability of a surrounding solution to cause a cell to gain or lose water

• describes the cell in comparison to its environment solute concentration

• there is a higher concentration of solute outside the cell so the water will move outside the cell.
• The cell will shrink and dry up inside as the water exits

• a higher solute concentration on the inside of the cell so the water will move inside the cell
• the cell will swell and grow

• hypotonic- the cell swells until it lyses (explodes)
• Isotonic- what the animal cell prefers
• Hypertonic- causes the cell to shrivel

• Hypotonic- what a plant prefers, best for turgor pressure
• Isotonic- the cell becomes flaccid
• Hypertonic- the plant cell is shriveled in a process called plasmolysis

• passive transport
• facilitated diffusion
• osmosis

• a cell having to transport something up and against its concentration gradient
• a Sodium Potassium Pump in neurons
• in exocytosis or endocytosis- movie large quantities of things

moves things OUT of the cell

• a vesicle will move to the plasma membrane and the membrane of the vesicle will fuse with the plasma membrane allowing an opening to dump out the contents of the vesicles
• cells are secreting things

moves things into the cell

• a protein in the membrane is triggered and the plasma membrane pinches into a pocket and the plasma membrane closes back up
• the mechanism of how cells eat and drink

1. phagocytosis- cellular eating- used by some immune cells
2. pinocytosis- cell drinking- the import of large quantities of water all at once