ch 3: cells and their functions

but its basically ap bio

plasma membrane

selectively permeable

regulates entry & exit → equilibrium/homeostasis

amphipathic

phospholipid bilayer has a polar phosphate head and nonpolar fatty tails

phospholipid bilayer

makes up cell membrane with polar phosphate head and nonpolar fatty tails

amphipathic

phosphate head

polar, has charge, hydrophilic (loves H2O)

includes membrane protein receptors & glycoproteins

outer portion of cell membrane

membrane protein receptors

transmembrane, peripheral → for transport in, for ligands (hormones)

transmembrane

thru membrane

glycoproteins

insulin receptor, blood type antigens (ABO), cell ID

fatty tails

nonpolar, no charge, hydrophobic

unsaturated fatty acids = fluidity

repel anything charged or polar

nonpolar ligands

unsaturated fatty acids

fluidity

nonpolar ligands

ex: lipids like estrogen

diffuse thru tails & into cell to its receptor = influence activity transcriptionally

transcriptionally

acting in nucleus/on DNA

cholesterol

connects phospholipids, keeps fluid-like

how something moves in/out of cell

polarity dictates this

cell transport protein

help large, polar things into cell that would otherwise be repelled by the fatty tails

concentration gradient

difference of concentration between two areas → move things Hi to Lo → needed to move things in biological systems

passive transport

does NOT require ATP energy

molecules move down/with a concentration gradient → Hi to Lo

ex: simple diffusion, facilitated diffusion, osmosis

simple diffusion

things travel down concentration gradient Hi to Lo → equilibrium

ex: GASES : O2, CO2, H2

Facilitated Diffusion

charged ions/solutes, large molecules, & polar diffuse thru carrier protein → skip fatty tails

ex: Amino acids, Na+ (sodium), Glucose (POLAR!)

Osmosis

solvent (h2O) diffuses down/with concentration gradient using aquaporin proteins

solute

what gets dissolved. salts, sugars, amino acids

solvents

what does the dissolving. H2O

isotonic solution

same solute & solvent concentration intra&extracellular

no net transfer/diffusion of H2O. Homeostasis/equilibrium

effect of isotonic environment cell is in

hypotonic solution

more H2O, less solute OUTSIDE cell

lysis

cell burst as H2O diffuses into cell

effect of hypotonic environment cell is in

hypertonic solution

less H2O, more solute OUTSIDE cell vs inside

kids with too much sugar are hyper

intracell

inside cell

crenation

cell shrinks as H2O diffuses outside of cell

effect of hypertonic environment cell is in

osmotic solute

any substance dissolved in a liquid solvent—such as water—that creates osmotic pressure and draws water across a semipermeable membrane

ex: miralax draws water into colon

salt (solute)

water follows…

osmolarity

salt to H2O ratio in blood

active transport

up/against concentration gradient : lo → Hi

uses pump or ATP

primary active transport

using ATP

ex: Na+/K+ pump

antiport

active transport, against

ex: Na+/K+ pump

Na+/K+ pump

active transport protein that uses ATP to pump 3 Na+ out and 2 K+ in

secondary active transport

goes from lo to Hi using Na+ gradient as energy → help glucose go in at the same time

ex: Na+-glucose symport

symport

together

ex: Na+-glucose symport

endocytosis

active transport of bringing things into cell using a lipid vesicle

ex: Clathrin mediated, flu

Clathrin mediated

endocytosis

receptors from pits and clathrin protein helps w/ invagination (folding inward itself) & vesicle formation

flu gains entry this way

exocytosis

active transport of bringing things out of cell using a lipid vesicle

ex: calcium dependent, neurotransmitters release

calcium dependent

exocytosis

release of neurotransmitters like dopamine, acetylcholine (for muscles)