Unit 3 AP BIO

cell theory

all living things are composed of cells, cells are the basic unit of structure in all living organisms, cells are only creating from already existing cells

cell membrane

the membrane at the boundary of every cell, selective barriers, made of phospholipids and proteins, bifacial, carbohydrates are on the outside

phospholipid composition

glycerol, two fatty acids, phosphate
hydrophyllic head, hydrophobic tail

fluid mosaic model

refers to the way the phospholipids and proteins behave in a membrane; fluid refers to the bilayer, mosaic refers to the floating proteins

nice molecules

small, nonpolar, uncharged

diffusion

movement down a concentration gradient, high to low; happens until equilibrium is reached; affected by concentration, temperature, pressure, particle size, mixing

osmosis

diffusion of water, PASSIVE transport, high to low

aquaporin

transport protein for water

tonicity

the concentration of solute outside relative to a cell’s solute

isotonic

cell and water are EQUAL in solute concentration, no net movement, no change in cells size

hypotonic

outside has less solute than inside, water moves INTO the cell, increases cell volume

hypertonic

outside has more solute than inside, water moves OUT of the cell, decrease in cell size

facilitated diffusion

transport protein that helps materials through the cell membrane, PASSIVE TRANSPORT, high to low

active transport

movement across membranes that DOES require cellular energy

passive transport

movement across membranes that DOES NOT require cellular energy

carrier-mediated transport

active transport of materials into the cells AGAINST the concentration gradient, low to high

exocytosis

moves bulk material out of cells

endocytosis

moves bulk material into cells

endosymbiotic theory

eukaryotic cells came from a symbiosis of prokaryotic cells

receptor mediated

uses receptors to catch specific kinds of molecules

protein pathway

ribosomes, RER, golgi apparatus, vesicles, cell membrane

g-protein linked

plasma membrane receptor, works with “g-protein”, very diverse and widespread in function

g-protein

an intracellular protein with GDP or GTP

GDP

an inactive protein 

GTP

an activate protein, the protein binds to another protein and alters its activation, activated state is temporary

intracellular signals

proteins located in the cytoplasm or nucleus that receive a signal that CAN pass through the cell membrane, activated protein turns on genes in nucleus

signal-transduction pathways

the further amplification and movement of a signal in the cytoplasm, uses protein kinases as relay protein

protein phosphorylation

the addition of Pi to a protein, which activates the protein

amplification

one signal activates many molecules

cellular responses

make a protein, cytoplasmic regulation, transcription regulation in the nucleus (dna>rna)

positive feedback loop

amplifies a response

negative feedback loop

returns an organism to its normal state

regulation

cells need to control cellular processes

environmental stimuli

cells need to be able to respond to signals from their environment

paracrine

local chemical communication

synaptic

local communication between neurons

long distance communication

hormonal communication

direct contact reception

molecules can flow directly from cell to cell without crossing membranes, cell-cell recognition

signal molecule reception

the actual chemical signal that travels form cell to cell

receptor molecules

usually made of protein, change shape when bind to a signal molecule, transmits information from the exterior to the interior of a cell

transduction

passing the signal

response

cellular changes because of the signal