Plasma membrane

MCAT

triacylglycerol and fatty acids:

where are they found?

Act as?

found in lower levels in the membrane act as phospholipid precursors

Function of glycerophospholipids

replace one fatty acid with a phosphate group which is often linked to other hydrophilic groups

cholesterol function in plasma membrane

lots of it in the membrane and it contributes to membrane fluidity and stability

waxes function in membrane

small ampunts if at all more common in plants function in water proofing and defince

transmembrane proteins vs embedded proteins vs membrane-associated proteins

transmembrane proteins:1 or more hydrophobic domains(usually receptors/channels)

embedded proteins: part of catalytic complex or involved in cell communication

membrane-associated proteins: may act as recognition molecules or enzymes

Gap junctions vs Tight junctions vs desmosomes and hemidesmosomes

Gap junctions: rapid exchange of ions and other small molecules between adjacent cells

Tight junctions: prevent paracellular transport not intercellular transport

desmosomes and hemidesmosomes anchor ⚓️ layers of epithelial tissues together

osmosis pressure

Osmotic pressure is the pressure required to stop the net flow of solvent (like water) across a semipermeable membrane from a less concentrated solution to a more concentrated one, aiming to equalize solute concentrations

passive vs active (primary and coupled \)

Passive transport: higher concentration to lower (simple diffusion doesn’t require transporter, osmosis is water fusion across selective membrane and facilitated diffusion require transporter)

Active primary requires ATP secondary or coupled is when the the movement of two substances across a cell membrane simultaneously, where the energy from one substance moving down its concentration gradient powers the other substance's movement, often against its own gradient

Na+/ K+ATPase ration of ions in vs out

main function is to maintain low concentration of sodium (Na+) ions and high concentration of (K+) ions in the cellby pumping 3 sodium out for every 2 potacium in this maintains negtive charge in the cell

trans phospholipid does not contribute to membrane fluidity because…

trans increases melting point and decreases membrane fluidity