7. Flashcards
(14 cards)
polar
molecule carries a charge
hydrophillic
non polar
molecule does not carry a charge
hydrophobic
cytoplasmic membrane
8-10 nm wide
embedded proteins
stabilized by H bonds and hydrophobic interactions
-mg2+ and ca2+ help stabilize membrane by forming ionic bonds with negative charges on the phospholipids
-somewhat fluid
membrane proteins
-gram negative bacteria, interacts with a variety of proteins (periplasmic proteins) that bind substrates or process large molecules for transport
inner surface of cytoplasmic membrane
interacts with proteins involved in energy-yielding reactions and other important cellular functions
integral membrane proteins
firmly embedded in the membrane
peripheral membrane proteins
on portion anchored in the membrane
archaeal membranes
- ether linkages in phospholipids of archaea
- bacteria and Eukarya have ester linkages in phospholipids
- archaeal lipids lack fatty acids; have isoprenes
- major lipids are glycerol diethers and tetraethers
- can exist as lipid monolayers, bilayers or mixture
lipid monolayers membranes are
extremely heat resistant
commonly found in hyperthermophilic archaea (grow at temps about 80 degrees C
Membrane function
permeability barrier
-polar and charged molecules must be transported
-transport proteins accumulate solutes agains the concentration gradient
PROTEIN ANCHOR
-holds transport proteins in place
ENERGY CONSERVATION
-generation of proton motive force
permeability barrier
prevents leakage and functions as a gateway for transport and nutrients into, and wastes out of the cell
protein anchor
site of many proteins that participate in transport bioenergetics and chemotaxis
energy conservation
site of generation and dissipation of the proton motive force
ester phospholipids
glyercol 2 fatty acids phophate side chain amphipathic
