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45 Cards in this Set

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Four factors affecting PERMEABILITY:
1. size--bigger=harder
2. soluability in lipid
3. ionic charge of molecule
a. bigger charge=bigger hydration shell
b. proteins--the charge
4. presence or absence of transport protein for that molecule
Passive transport:
Does NOT have to use energy (ATP) to move across membrane
Characteristics of active transport:
--Does use ATP to move across membrane
--can move against concentration gradient
--has to transport proteins
--carriers will be: specific, competitive, saturated
--sometimes more than one thing is transported at same time---co-transport
Characteristics of DIFFUSION:
-does not require a cell
-net movement of molecules from area of high concentration to area of low concentration
-movement is random
-change direction more often on side with more
-more will move from area of high concentration to low concentration
Concentration gradient:
Two adjacent areas and one has higher concentration than the other
Equilibrium:
When no net movement-all movement is equal
Factors that effect DIFFUSION:
1. permeability of membrane to substance; lipid soluble or water soluble.
2. size of concentration gradient
3. dimensions of pathway (cell membrane)
-microvilli will increase it
-thickness of plasma membrane=harder to get through
-surface area
4. molecular weight/size of molecule
-larger size=less diffusion
- O2, H2O, CO2 all thru easily
Facilitated diffusion:
-diffusion helped--carrier proteins will help molecule get across membrane
-no energy required
-carriers are specific
-competition--other substances will try to compete
-can be saturated
Specificity:
When carriers will only move one kind of thing across membrane
Co-transport:
When more than one thing is transported across the membrane at the same time
Symport:
Moving in same direction at same time
Antiport:
Moving different things in opposite directions at same time
Primary active transport:
When you spend ATP as the first transport occurs

Ex: sodium potassium ions Na+ K+ (Na+ K+ pump)

moves 3 Na+ out of cell
moves 2 K+ into cell

---for every 1 ATP cell uses
Secondary active transport:
-initial movement is coupling diffusion of one molecule to transport of another molecule against its concentration gradient
--use energy in different place to transport diffused item back out
Phagocytosis:
Moving into cell "cell eating"
Pinocytosis:
Moving into cell

Requires ATP
Receptor mediated endocytosis:
Moving into cell

Requires ATP
Exocytosis:
Moving out of cell

requires ATP
Osmosis:
-NET movement of H2O from area of high H2O concentration to area of low H2O concentration
-H2O will move to dilute area that is more concentrated
-passive
-does not require energy at all times
-there is chemical disequilibrium between cytoplasm and extracellular
-uses energy to maintain disequilibrium
-H2O can easily move into different body compartments/across plasma membranes
-water moves to restore osmotic equilibrium
Solution:
Solvent + Solute

Amt of What was added
H2O
Concentrations:
If more particles of solute= less water

If more water= less particles

H2O concentration differs because solute concentration differ
Osmotic pressure:
-driving force for H2O caused by the difference in H2O concentration between solution and pure H2O
-how much pressure would you have to apply to stop or oppose the movement of H2O down its gradient
Osmolarity:
number of moles of solute particles per liter of solution
Molarity:
number of moles of substance per liter of solution
Isosmotic:
same--equal number of solute particles in two solutions--no net movement
Hyperosmotic:
more--larger number of solute particles than other solution
Hyposmotic:
less--fewer number of solute particles, but has more H2O
Tonicity:
classified solutions based on what they do to cell size
Isotonic:
cells stays same size
Hypertonic:
H2O leaves and cell shrinks (crenation)
Hypotonic
Cell size increases, water goes into cell
Lysis:
When cell gets so big it explodes
Osmotically active:
Cannot get across
How much water crosses membrane every second?
100x volume of cell in water
Cellular communication:
--gap junctions-- between cells
-cell junction--have protein that extends across cell membranes of two cells and hole down the center
--size limits what can go through
Paracrine:
Chemicals released effects other nearby cells
Autocrine:
Chemicals released effects cells that released them
Can chemicals do both paracrine and autocrine functions?
Yes, most can with stimulation

ex: mast cells release histamine--effect blood vessels
Cytokines:
chemical communication, big variety, can act as paracrine and autocrine, but also get into blood and can effect cells at distance

ex: immune system--interferons
Endocrine system:
-long distance
-only chemicals, hormones
-hormones travel in blood-can go anywhere
-only cells that will respond are ones with receptor for that hormone
Nervous system:
-both electrical and chemical

--electric: graded potential
action potential
--chemical:
neurotransmitters
neuromodulators
neurohormones
Neurotransmitters:
signal nearby cell
Neuromodulators:
nearby cell effects are different
Neurohormones:
released by neurons but get into blood and go everywhere
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