Lab 1 - Study Guide Flashcards
What is Fick’s law?
J = -DA(dC/dx)
What do the things in Fick’s law stand for?
J = net flux of a solute A = the cross sectional area through which the diffusion occurs dC/dx = the concentration difference between two points separated by a distance of x D = the diffusion coefficient for the diffusing molecule
For Fick’s equation, what does D depend on?
Temperature, the molecular weight of the solute, and interactions between solute and solvent
Do smaller or larger molecules move faster at a given temperature?
Smaller
The greater the concentration difference, the _____ the rate of diffusion
Greater
Explain simple diffusion
Refers to a process whereby a substance passes through a membrane without the aid of an intermediary such as a integral membrane protein
Explain facilitated diffusion
Is the process of spontaneous passive transport (as opposed to active transport) of molecules or ions across a biological membrane via specific transmembrane integral proteins.
Explain active transport
The movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy.
Explain the concept if saturation of glucose carriers
There are only a certain number of carrier proteins for a given solute and under the conditions of high solute concentration, all of the carriers may be being used, thus there is a maximum rate of transport which is determined by the number of available carrier proteins. Neither simple diffusion nor diffusion through pores can be saturated
How would you design at experiment to illustrate saturation?
Put the concentration of glucose higher than the number of glucose carriers
Osmosis definition
A process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane
Osmolarity defintion
The concentration of a solution expressed as the total number of solute particles per liter.
Osmotic pressure defintion
The pressure that would have to be applied to a pure solvent to prevent it from passing into a given solution by osmosis, often used to express the concentration of the solution.
Hypertonic, isotonic, and hypotonic definition
- Isotonic solutions are two solutions that have the same concentration of a solute.
- Hypertonic solution is one of two solutions that has a higher concentration of a solute
- Hypotonic solution is one of two solutions that has a lower concentration of a solute
What is the relationship between osmolarity and osmotic pressure?
Osmolarity - the measure of solute concentration
Osmotic pressure - the pressure that would have to be applied to a pure solvent to prevent it from passing into a given solution by osmosis, often used to express the concentration of the solution.
Surface tension defintion
A force that acts to minimize the SA of an interface between two fluids
Surfactant definition
A substance that tends to reduce the surface tension of a liquid in which it is dissolved.
Amphipathic defintion
Having both hydrophilic and hydrophobic parts.
What are the factors of Laplace’s equation demonstrated in the bubble experiment? P=2T/r
P = the amount of pressure inside the bubble
T = surface tension
r = radius of the bubble
- Bubbles have large surface area, so they are unstable. Soap is a surfactant that makes the bubbles get smaller.
How does the law of Laplace describe the pressure in the heart, blood vessels, stomach?
Any hollow organ has tension produced by the muscular walls. This tension produces pressure inside the organ.
How do the results of the surface tension experiment relate to the sizes of alveoli in the lungs? To respiratory distress syndrome in infants?
Alveoli empty themselves because of surface tension. The alveoli of the lungs have surface tension that is partially responsible for their internal pressure.
- Infant disease = no surfactant produced
