Lab 2 Flashcards
What type of substance can pass through the cel membrane without assistance?
small non-polar l=molecules like o2 co2, fatty acids, steroid hormones, and fat-soluble vitamins like vitamin D.
Does the steepness of the concentration gradient affect how many molecules can move across the membrane?
yes, the bigger the difference in concentration btwn the two sides of the memb, the more net mvmt there will be. so if Na is really low on one side and really high on the other there will be more net mvmt then if it was like 60-40.
When solutions are at equilibrium is there still net movement?
no bc the concentration is not changing on either side. however there is still mvmt of molecules across the membrane, just in an equal way.
Why did the thistle tube with 125% sucrose see the most mvmt of the meniscus when placed inside a beaker with distilled water?
bc osmosis occurred a lot. so, water wanted to go into tube that had a low water conc and a high solute conc, so it did. means that volume of meniscus increased bc water rushed into the tube from the beaker.
What is osmotic pressure?
pressure needed t okeep H2O from diffusing into a solution. so the higher the conc diff btwn both sides is, the higher the osmotic pressure will be in the side that has the lower water conc (bc its trying to keep water from coming in). so water always comes from high conc to low conc, or low OP to high OP.
What is hemolysis?
bursting of a red blood cell due to too much water.
Why are substances where bursting has occurred look clearer?
bc there are no membranes getting in the way bc they have burst
What would cause hemolysis in a cell?
distilled water going into solution bc now plasma conc of water is high so water wants to go from high to low, and therefore goes into cells causing them to burst,
What is isotonic?
solute conc and solvent conc are the same on both sides of the membrane.
What is hypotonic?
inside the cell has higher [water] and lower [solute].
What is hypertonic?
inside the cell has higher [solute] and lower [water].
What is the normal concentration of solutes in a rbc?
0.9 % saline (naCl) solution.
What are the factors that will influence if net mvmt of a solute occurs across a membrane?
the permeability of the membrane to the solute (how much of it can pass and can it pass), and the concentration of that solute on either side of the membrane. ie is it going from high to low.
When submerged in a beaker of distilled water, a thistle tube containing which of the following solutions would have the highest osmotic pressure? a) 0% sucrose b) b) 10% sucrose c) 50% sucrose d) 125% sucrose
d) 125% sucrose
The RBCs shown below (pic on phone in NB album) are likely surrounded by which type of solution? a) hypertonic solution b) hypotonic solution c) isotonic solution
a) hypertonic solution
