mixture of proteins and minerals.

functions:

• provide structure (aka scaffolding)
•  transmit info between cells

parameter at set point. system not changing, but energy is used.

requires balancing, trade-offs.

disturbance, response, and back to steady state.

moves in opposite direction of the disturbance.

continuing in direction of the disturbance.
moves further from the disturbance.

e.g. birth.

released by: almost any cell

pathway: interstitial fluid
communicates with: neighbor effectors

direct channels between adjacent cells (like tunnel between buildings that allow you to avoid the outside)

*stays intracellular

trait that favors survival.
due to natural selection.

genetic change (change in genetic templates)-- a species change, not an individual change.

resetting of set point.

use based, individual change, not a genetic change.

usually reversible

have a single electron in their outer orbit.
remove electron from another to get a pair in outer orbit-- oxidizing.

very effective in damaging pathogens but are indiscriminant and will take an electron from a pathogen or from one of out cells.

need to be neutralized.

unequal sharing of electrons

hydrophilic

lipophobic

equal sharing of electrons

lipophilic

hydrophobic

electrical attraction of opposites

strong without water--water breaks this bond apart, therefore will not be strong in the human body

avoiding polar-- weak bond.

creates connection between molecules trying to avoid water

regulates movement (in, out, within cell)

binds chemical messengers

holds cells in extracellular matrix

allows for cell's shape & motility (ability to move the cell)

allows for cell to cell contact (to create a gap junction, form tissue, etc)

main building block of plasma membrane

amphipathic-- has two polar heads and a nonpolar tail

spontaneously form bilayer, so tails avoid water

serve as channels, receptors, anchors

always amphipathic

not removable (INTEGRAL to membrane)

many transmembrane (completely cross membrane)

impact shape and motility of plasma membrane.

polar

associated with inside (cytosolic side) of membrane

allows for identification of cells-- can tell if cell is part of the body or not

allows for interaction between cells

short, branched carbohydrates that give the surface a "fuzzy" appearance

located on outside of membrane

type of junction

protein linkages between cells--hold cells together

like holding hands.

allows for interstitial fluid flow

joinging of plasma membranes (connected)

forms a band aorund the cell

blocks interstitial fluid flow

bound Pi transferred to ATP

e.g. ATP + X --> ADP + XPi

examples: glycolysis, krebs cycle, creatine in muscles

= electron transport system

energy input allows unbound Pi to bind ADP

diffusion

relationship to permeability, concentration gradient, surface area, distance

movement of things from high concentration to low concentration, until both sides are balanced out.

no energy cost, goes with gradient

small, nonpolar molecules can do this

as permeability goes up, diffusion goes up

as surface area increases, diffcusion increases

the bigger the concentration gradient, the faster diffusion will occur

as distance increases, diffusion decreases

change in electrical distribution

changes protein shape (which is dependent on electrical components)

like buttons on keys that unlock/open car door.

net diffusion of water across a membrane

from high to low water concentration

moves from low concentration of solutes to high concentration

total concentration of solutes in solution

[X] = # of X / volume

the greater the osmolarity, the less concentration of water--water moves toward lower water concentration so moves toward higher osmolarity

same concentration of nonpolar solutes on the outside of cell-- osmolarity in cell equal to osmolarity outside

no movement of water, volume stays the same

greater concentration of nonpolar solutes outside-- water will move towards higher osmol. outside of cell

cell shrinks

lesser concentration of nonpolar solutes outside cell-- water will move towards higher osmol. inside of cell

cell swells

occurs when a membrane is not soluble to solutes, only water, and there is no membrane movement (water trying to get into area that is already filled).

when membrane is semipermeable and immobile.

the greater the osmotic (osmol.?) difference, the greater the osmotic pressure.

membrane protein acts as a shuttle--like a revolving door, must be interacted with in order to get through.

bindings to proteins regulate transfer.

go with the gradient from high to low concentration, no energy cost.

based only on conformation/shape changes caused by binding--opens and closes gate.

shuttle can only take one molecule at a time, can be saturated (overloaded) because of this.

e.g. glucose

energy is lost-- almost always against concentration gradient (make a gradient)

based on conformation changes and ATP

primary and secondary forms

uses ATP directly

transport proteins=ATPase pumps, which creates gradients

e.g. sodium potassium ATPase pump

1. ATP binds
2. protein shape change so that..
3. 3 Na+ bind, shape change so enzyme does enzymatic activity--
4. Hydrolysis of ATP (forms ADP and Pi)
5. phosphate stays
6. orientation flip (opens to outside of cell rather than inside) -- changes shape so Na+ is released
7. release Na+ --causes shape changed allows for 2 sites to open and become available
8. 2 K+ bind-- shape change which causes release of P (breaks K bond and releases energy)
9. orientation flip to orig. position
10. release of K

working to create a gradient

high sodium outside of the cell, low sodium inside; sodium is sent to outside where there is more so gradient is created

high potassium inside cell, low outside-- K+ sent into cell.

uses ATP indirectly

uses energy from primary active transport to move a second molecule against it's gradient.

an infold of the membrane-- moves objects from outside to inside of the cell

contains interstitial fluid

forms intracellular, membrane-bound vesicle

vesicle fusing with th membrane so particles can exit the cell

releasing the contents into interstitial fluid

percent of ligands activated

more affinity means more saturation

competitor binds to cell and there's no response

** blocking a pathway

competitor binds and there is a response

** activating a pathway

within nucleus or cytoplasm

ligand= nonpolar

result= always alters DNA use (greater or less with DNA)

if messenger is coming into a cell from plasma, need this because it protects the nonpolar ligand from polar plasma.

ligand= polar (no cell entry)

only first component in relay system, will need a second messenger, because first messenger cannot do whole job.

1. function as an ion channel (mechanically/ligand-gated). Result= change in charge distribution
2. function as an enzyme (tyrosine kinase). Result= cascade of phosphorylations
3. interact with JAK kinase (first messenger binds to receptor, which changes JAK kinase, which is attached to the receptor). Result= synthesis of new proteins
4. interact with g-protein