Lab 2 Quiz - anatomy physiology review for lab quiz 2 PDF

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anatomy physiology review for lab quiz 2...

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Cellular Transport Introduction - Movement of material across the cell membrane occurs by diffusion (passive or facilitated), active transport, or endocytosis/exocytosis - Extracellular fluid (ECF)- fluid outside the cell - Diffusion (passive or facilitated) - Simple, carrier-mediated, channel-mediated AND osmosis do not require ATP (metabolic energy) - Simple, carrier-mediated, channel-mediated AND osmosis move down their concentration gradient from high to low - Facilitated diffusion (carrier-mediated, channel-mediated) requires special carriers - Passive diffusion (simple) is dependent on the concentration of materials on either side of the membrane - *if the membrane is permeable to a specific substance, then the rate of diffusion will be directly related to the difference in concentration of the substance on the two sides of the membrane - Other variables that enter into the rate of diffusion are the cross-sectional area of the membrane and the diffusion coefficient- the permeability of the membrane to a given substance. - Fick’s Law of Diffusion (rate of diffusion) - Q = DA (C1 - C2) - Q = rate of diffusion - (C1 - C2) = the difference in concentrations of a substance on either side of the membrane - A = the cross sectional area of the membrane - D = diffusion coefficient - The individual diffusing molecules spread out evenly until they reach equilibrium where no further net movement occurs - *the free energy of the solution will be lower and the entropy- disorder, will be higher AFTER equilibrium is reached - (this makes sense because after equilibrium is reached, the molecules don’t know where they’re going/randomness increasing entropy--- free energy is lower because it’s greatest at the beginning) - Diffusion takes place quickly in a gas as opposed to solid or liquid - Example of diffusion: The concentration gradient is inward when talking about oxygen in our cells. We have less oxygen inside than we do outside, and considering concentration goes from high to low, the oxygen from the outside is going inward to the intracellular fluid - Osmosis- the movement of water through a semipermeable or selectively permeable

membrane from an area of low solute concentration to high solute concentration (also

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known as high water concentration to low water concentration) ex) 0.1M → 1.0M - Isosmotic- if the solutions are of equal concentration and there is no net movement of water - Hypoosmotic- lower solute concentration, higher water concentration - Hyperosmotic- higher solute concentration, lower water concentration - ***Net movement of water is always from the side with the higher water and lower solute concentration (hypoosmotic) to the side with lower water and higher solute concentrations (hyperosmotic)*** Osmotic pressure- a quantitative measure of the force necessary to resist osmosis of pure water into a solution - Osmotic pressure is proportional to the concentration of solute in the solution therefore hypoosmotic solution will always have a lower osmotic pressure than the hyperosmotic one - Osmotic pressure of pure water is 0 - Osmosis is a colligative property- dependent only on the number of particles present, not their type - One mole of an electrolyte will exert more osmotic pressure than one mole of a nonelectrolyte like ex) glucose because electrolytes dissociate into more than one particle - NaCl will exert twice the amount of pressure of 1 mole of glucose because NaCl will dissociate into sodium and chloride ions - CaCl2 will exert triple the amount of pressure of 1 mole of glucose Π V =nR T (for a solution) - PV = nRT (for a gas); - Rewritten: Π=(n/ v)RT - (n/v) is the number of particles in a volume which is equal to molar concentration (C) - Rewritten again: Π =iCRT Π = osmotic potential - i= the number of ions dissociated from each molecule in a solution - C = the molar concentration of the solution in moles/liter - R = the gas constant (0.082 liters-Atm/degree-mole) - T = the absolute temperature (°K) - Osmometer- two chambers separated by a semipermeable membrane that allows water movement but not solute movement - The direction, amount, and speed of osmosis are related to… - The difference in osmotic potentials of the solutions on either side of the membrane. - If the number of ions dissociated (i) is the same for the two solutions then you can use

Π =iRT (C 1−C 2) - (C1 - C2) = the concentration gradient in moles/liter across the membrane - Active transport goes against its concentration gradient from low to high - It also requires a carrier to move the substance through the cell membrane - It also requires energy (ATP) for the movement The expression of solute concentrations 1. Percentage solutions a. Weight/volume (W/V) number of grams of solute /100 mL of H 2O ... i. ii. A 1% glucose solution would be 1 gram/ 100 mL b. Volume/volume (V/V) number of milliliters of a substance /100 mL of H 2 O i. ii. A 1% ethanol solution would be 1 mL/ 100mL 2. Molar solutions (M) one mole of glucose /1 liter of water a. Labs 1.Diffusion- Effects of Temperature on Diffusion Rate Lab consists of filling 2 beakers, one with cold water in an ice bath, one with warm water and insert a drop of tinted dye. Is the concentration of the colored part of the solution greater at the beginning or end of the experiment? - The concentration is greater at the beginning because the molecules have not been dispersed into random motion yet and have not spread apart Is the free energy of the solution greater at the beginning or end? - The free energy is greater at the beginning Is the entropy of the solution greater at the beginning or at the end? - The entropy is greater at the end. When equilibrium is reached, entropy is greater than free energy Is there a difference in the rate of diffusion between the room temperature water and the cold water? - Yes If yes, is the rate faster or slower in the room temperature water? - The rate is faster in the room temperature water because heat causes reactions to be faster -

2. Effects of Molecular Weight on Diffusion Rate Diffusion in Air Graham’s law= rate of diffusion is proportional to the square root of molecular weights 3. Diffusion in viscous solutions similar to that of cytoplasm of living cells Lab consists of filling petri dish with 2 sets of wells, one ½ cm apart and the other 1 cm apart of 1M solution of sodium sulfate and 1 M barium chloride solution

Record the time it takes for the barium and sulfate ions to meet and form a white precipitate. Which ion traveled the farthest in that time span? - It took about 5-10 mins and sulfate Calculate the relationship between diffusion time and distance - It took longer for the wells that were 1 cm apart as opposed to ½ cm apart because they are farther apart, indicating that there is a direct relationship between diffusion time and distance 4. Osmosis Molasses dialysis tubing In the experimental set up, on which side of the dialysis tubing was the concentration of molasses initially higher? - The inside of the dialysis tubing Did the level of the solution in the pipette increase? If so, by how much? - Yes, by 1-5 mL Which molecules passed through the tubing? - The water molecules Why is there only a one way net movement of molecules in this system? - Because we are using a semi permeable membrane, it became evident that the molasses solution was too big to diffuse and pass through the dialysis tubing What part of the cell does the dialysis tubing represent? - The cell membrane Dialysis- when water diffuses from one side to the other in the process of osmosis and small molecules ALSO diffuse across the membrane 5. Osmosis in living animals Using mouse blood in different solutions Hemolysis- when red blood cells are placed in a hypotonic solution, they swell and burst Crenate- when red blood cells are placed in a hypertonic solution, they will shrink What happened when distilled water was added to the blood? - The blood cells swell up and become hypotonic because the water goes into the cells What happened when 0.9% NaCl was added to the blood? - When 0.9% NaCl is added to the blood, it becomes isotonic What happened when 10% NaCl was added to the blood? - When 10% NaCl is added to the blood, it becomes hypertonic because there’s a high solute and because water leaves the cell and it shrinks Add DI water to the 10% solution. Did the blood cells change? Why? - Yes, the cells swelled up and became somewhat hypotonic/normalized because of the addition of the DI water Would you expect normal saline to be hypotonic, hypertonic, or isotonic to the patient’s tissues? - hypo...