cell transport

cell transport

active transport
1. active transport requires energy
2. L --> H
3. atp molecules used to move molecules
4. "going against the flow"
5. 3 types of active transport: - 1. active transport pumps 2. endocytosis (out) 3. exocytosis (in)
  1. endocytosis- cell uses vesicles to move extremly large substances into cells
  2. exocytosis - cell uses vesicles to move large amounts of substances out of cell
  3. active transport pump- proteins that use ATP energy to transport molecules into or out of the cell membrane, against the consentration gradient. Example of Active Transport Pump is the sodium - potassium pump
passive transport
1. molecues moving through the membrane from high to low concentrations without energy
2. NO ENERGY
3. high --> low
4. there are 3 types of passive transport. - 1. simple diffusion- small nonpolar 2. facilitated diffusion- large polar 3. osmosis- water
  1. simple diffusion- small non polar molcules that are able to move through the membrane towards a low concentration til equilibrium
  2. facilitated diffusion- the movement of a large polar or polar molecule through the cell membrane with the help of transport proteins
    1. 2 types of transport proteins
      1. 1) channel proteins act like a tunnel
      2. 2) carrier proteins grab molecules and moves them through the membrane
  3. osmosis- the movement of water through the cell membrane. Water can move in 3 ways in relation to the cell membrane
    1. 1) hypertonic: water moves OUT. -more solute (salt) outside the cell than inside so water moves out. -cell shrivels, wrinkles, and shrinks eventually
    2. 2) hypotonic: water moves IN -more solute (salt) inside the cell than outside so water moves in -cell swells and could potentially burst/pop
    3. 3) isotonic: equal net movement. -equalibrium is met; call stays the same size -there is an equal amount of solute inside and outside of the cell
structure of Cellmembrane
1. the cell membrane is primarily composed of 3 different organic compounds. 1)phospholipids 2)proteins 3)carbohydrates
  1. phospholipids- a specialized lipid used in the formation of the cell membrane. Consist of two parts. Phosphate head- polar. Fatty acid tails- non-polar
    1. lipid bilayer: two of phospholipids. -nonpolar tails point inwards -polar heads to the inside and exterior of the cell
      1. *why do the tails all point inwards and the heads point outwards? - heads are polar so they attract water and tails are nonpolar so they repel water
      2. - hydrophobic is the repulsion of water -hydrophilic is the attraction to water
  2. proteins- 2 major classifications of membrane proteins. 1) integral transport proteins- tubes that allow large substances into and out of the cell 2) receptor proteins- do not have a tubular opening and can be integral or peripheral. Used to sense cell surrounds
  3. carbohydrates- extend outward from the cell membrane and work like "cell name tags". Will only be found on the outside.
    1. they are green, hexagon shape, and stick out on the top or bottom
2. the cell membrane controls the movement of molecules into and out of the cell to maintain homeostasis
  1. homeostasis is the ability of living organisms to control and maintain a stable internal enviorment
    1. this property is called semi- permeable and allows for homeostasis
3. The cell membrane controls what can and cannot enter the cell
4. concentration gradient- when molecules in a given space are not dispersed evenly
  1. molecules in a concentraion gradient will always naturally (without energy) move to obtain equilibrium
5. concentration: the amount of something in a given space are not dispersed evenly
  1. can be low, high, or at equilibrium

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	Created by Cheyenne Cooke over 7 years ago