Exam 3 - Lecture 33 (Fluid Interaction) Flashcards
What is concentration?
Amount of a specific substance (solute) in a unit amount of another substance (solvent).
What is a solute?
Thing that changes physical appearance in a solution.
What is a solvent?
Thing that stays the same in a solution.
What are 3 ways in which concentration can be expressed?
- %
- Molarity/molality
- Electrochemical equivalence
What are the units for %?
parts/100
What is the unit for molarity?
moles/L, kg, M
What are the units for electrochemical equivalence?
Eq/L
How many molecules are in 1 mole?
6 x 10^23
What is the concentration of physiological saline as a %? Molarity? Electrochem. equivalence?
% = 0.9% NaCl sln
Molarity = 150 mM
Electrochem. eq. = 300 mEq/L
Concentration gradients are critical in driving _____ across _____.
particle movement; biological membranes
What is the structure of a phospholipid?
Hydrophilic head with a hydrophobic (fatty acid) tail
What 2 things CAN’T cross the phospholipid membrane?
- Charged particles
2. Polar molecules
What 2 things CAN cross the phospholipid membrane?
- Lipid soluble molecules
2. Small polar molecules (water)
How many passive and active mechanisms are there for movement of things across biological membranes?
2 passive and 2 active
What is diffusion and what type of mechanism does it employ?
Movement of particles from [high] to [low];
passive (no energy req.)
Rate of diffusion depends on _____ and _____.
size of gradient; permeability of membrane
How does gradient and temperature affect diffusion?
Higher gradient/temp = higher difffusion
Lower gradient/temp = less diffusion
What is facilitated diffusion and what type of mechanism does it employ?
Movement of particles from [high] to [low] with the help of pores, channels, or carrier proteins;
passive (no energy req.)
What types of molecules utilize facilitated diffusion?
charged molecules
If particles are charged they can move down an _____ gradient.
electrical
Concentration gradient + electrical gradient = _____?
electrochemical gradient
What two things make up the electrochemical gradient?
[ ] gradient + electrical gradient
Charged molecules want to move _____ their electrochemical gradients through _____.
down; pores
What is active transport and what type of mechanism does it employ?
Movement of particles from [low] to [high] against the electrochem. gradient;
Active (req.energy) - hydrolyzes ATP –> ADP
How is energy generated in active transport?
ATP –> ADP
What does ATP –> ADP do to conformation?
changes it
What is secondary active transport and what mechanism does it employ?
Movement of molecules across a biological membrane against gradient;
Active (req. energy) but gets it from other ATP-producing processes in the cell
What is another name for secondary active transport?
co-transport
How is energy generated in secondary active transport/co-transport?
Potential energy created by active transport elsewhere (NOT ATP hydrolysis)
What is an example of secondary active transport?
Glucose movement in the kidney
What is a symporter?
Co-transport in the SAME direction
What is a antiporter?
Co-transport in OPPOSITE directions
What is osmosis?
Movement of water across a selectively permeable membrane from dilute to concentrated solution.
(high [water] –> low [water])
(low osmolarity –> high osmolarity)
What does it mean if a sln is dilute?
High [H2O]
What does it mean if a sln is concentrated?
Low [H2O]
What is an effective osmole?
Molecule (ex: glucose) that cannot cross a membrane and so it generates osmosis.
What is osmolarity/osmolality and what are its units?
[ ] of osmotically active atoms; osmoles/L, kg
Rank the following from low to high osmolarity: plasma/skim milk, urine, tap H2O
Tap H2O, plasma/skim milk, urine
A dilute solution has _____ osmolarity.
low
During osmosis, water moves from _____ osmolarity to _____ osmolarity.
low; high
What is tonicity?
Overall [ ] of effective osmoles in a sln; [ ] of things that actually cause osmosis.
What is an osmole?
Something that generates osmotic pressure.
What are the 3 types of tonicity?
- Hypotonic
- Hypertonic
- Isotonic
What is a hypotonic solution?
Sln with lower effective osmolarity than another
EX: RBCs swell in hypotonic fluid bc H2O enters the cell
What is a hypertonic solution?
Sln with higher effective osmolarity than another.
EX: RBCs shrink in a hypertonic soln bc H2O leaves the cell
What is an isotonic solution?
Sln with same effective osmolarity as another.
