Ch. 5 - Cellular Function

• maintain cell shape • coordinate changes inside and outside the cell via attachments to the cytoskeleton and EM • receptors for chemical messengers from other cells (cellular communication via signal transduction) • enzymes that catalyze reactions • glycoproteins are involved in cellular recognition (help to recognize self as self and alert the immune system to intruders) • transport of substances across the membrane

• automatically forms when phospholipids is when mixed with water • surround and encase areas of water resulting in Walter filled bubbles surrounded by lipid bilayers

• cellular membranes are semi-premiable - all may not pass - requires no energy

• movement of a substance down its concentration gradient from an area of higher to lower concentration • diffusion of different substances is independent • happens in air as well as water

diffusion in both directions doesn’t stop, but is equal, so there’s no net change in concentration

• passive (requires no energy) - needs transport protein to cross the membrane down its concentration gradient

• diffusion of water across a membrane • the solute molecule is too large to cross the semi-permeable membrane but water can cross the membrane quickly (3 billion aquaporin/s)

• iso=the same - concentration of diluted in solution is the same inside and outside the membrane

• hyper=lots • concentration of splinted is greater than the concentration inside the cell (cell is hypotonic relative to the solution)

• hypo=beneath/below - concentration of solutes is less than the concentration inside the cell (cell is hypertonic relative to solution)

• requires transport protein • pumping solute against its concentration gradient • requires energy which it gets from ATP

exocytosis or endocytosis

• way to get large substances exported from the cell - exo=outside kytos=cell

• endo=inside - way for cells to get things from the outside of the cell to inside of the cell

• phagocytosis (cell eating) • pinocytosis (cell drinking) • receptor-mediated endocytosis