components of a semipermeable membrane
phospholipid bilayer 40%
proteins 50%
carbohydrates 10%
2 types of proteins
integral= completely in plasma membrane
and
peripheral= attached to surface of bilayer
integral proteins
everything interacting with lipids needs to be non-polar
-6 functions
integral protein functions
transporter
creates passageways
integral protein functions
enzyme
speed up chemical reactions
integral protein functions
cell surface receptor
incoming signals and reactions
integral protein functions
cell surface identity marker
allows recognition so keep things from fighting cells
integral protein functions
cell to cell adhesion
allows cells to grab onto eachother when becoming tissues. organs etc.
integral protein functions
attachement to cytoskeleton
support cell’s structure
peripheral proteins
-can serve as enzymes
-structural attachment to cytoskeleton
-cell surface identity markers (need carbs)
2 types of carbohydrates
glycoproteins= protein with carb attached
and
glycolipids=lipid with carb attached
both are cell sruface identity markers
3 types of cellular transportation
passive
active
bulk
passive transport
simple diffusion
osmosis
facilitated
all work along a concentration gradient
no energy needed
passive transport
simple diffusion
molecules pass through membrane without assistance
higher to lower concentration until equally dispersed
passive transport
osmosis
movement of wate rot balance concentrations
passive transport
facilitated diffusion
proteins create passageways
-channel proteins and carrier proteins
passive transport
channel proteins
allow passage of ions in either direction (regular door) across membrane
-ion channels can be gated based on needs
passive transport
carrier proteins
bind to molecules that they transport across the membrane (revolving door)
-can become saturated w/solute if concentration is high
3 types of tonicity
hypertonic= more solute (shriveled RBC)
hypotonic= less solute (swollen RBC)
isotonic= equal amounts of solute (normal RBC)
osmosis
active transport
requires energy to move molecules AGAINST their concentration gradient
- from low to high concentration
-needs ATP
-sodium potassium pumps
bulk transporter
endocytosis
exocytosis
bulk transporters
endocytosis
movement of substances into cell
-phagocytosis to engulf debris
-pinocytosis to enguld liquid
-receptor mediated = molecues bind with receptor protein and pull into cell together
bulk transporters
exocytosis
movement of substances out of the cell
-vesicles carry waste or hormones into membrane, vesicle fuses to membrane and releases waste.
-used in phagocytosis to rid engulfed debris
