Wk 1- The Cell Membrane

Functions of the cell plasma membrane The cell membrane is the gateway in and out of the cell • in • out

The cell plasma membrane The membrane is selectively - The membrane consists of a - - layer Hydro-outer Hydro- inner

Cell plasma membrane Passage through the membrane is either p- or a- P- does NOT require extra - A- does require extra - in the form of - - -

Mechanisms of transport through membrane Passive transport : Diffusion Diffusion can be either s- or f-

Passive diffusion Simple diffusion: moves through membrane - Facilitated diffusion: use - channels or carriers to diffuse - the plasma membrane

Mechanisms of transport Active transport: Not dependant on - gradients Requires - in the form of - - - Uses ion pumps to transport ions across cell membrane : - - pump

Mechanisms of transport Vesicular transport : Movement into and out of cell in sacs called - Entry into cell = -cytosis Entry out cell = -cytosis

Sodium potassium pump 1 molecule of ATP results in - Na+ pumped OUT of cell and -K+ pumped INTO cell

Osmosis The diffusion of - molecules across selectively permeable membrane Water molecules travel across membrane from - solute concentration gradient to - solute concentration gradient

Tonicity The effects of - pressure on cells Solution can be I-, Hypo- or Hyper-

Tonicity Isotonic= no net flow of water into or out of cell E- pressure ratio of solvent:solute concentration (E-) Hypotonic= water flows into cell as cell has higher concentration of solutes Solute concentration greater - cell , solvent enters cell = swell / l-

Tonicity Hypertonic= water flows out of cell as cell has lower concentration of solutes Solute concentration is greater - cell= solvent leaves cell, crenates/ s-

Concentration gradients Diffusion: movement is - concentration gradient from - to -

Adenosine triphosphate structure and function: ATP = adenosine and ? phosphate groups When energy is used loses ? phosphate and becomes A?P 1 molecule of ATP results in ? Pump = 3 ? pumped out of cell 2 ? pumped into cell