BIO 2301 LAB EXAM COMPREHENSIVE
REVIEW LAB 1 CSCC QUESTIONS AND
ANSWERS
Does the rate of diffusion change as the concentration gradient changes? -
ANSWER-Yes, as concentration gradient increases, rate of diffusion increases.
How do concentration gradients affect the direction of diffusion? - ANSWER-They
increase rate high to low.
Do solutes of differing masses diffuse at the same rates if concentration gradients
are the same? - ANSWER-No, bigger stuff diffuses slower, smaller stuff diffuses
faster.
If multiple solutes are present and diffusing, do they diffuse independently or do they
influence one another's diffusion? - ANSWER-INDEPENDENTLY
In facilitated diffusion, what determines the rate of diffusion: the concentration
gradient or the number of carriers? - ANSWER-Concentration gradient and number
of carriers BOTH affect rate of diffusion. Bigger gradient and more carriers is faster!
What kinds of osmotic effects do you expect hypotonic, hypertonic, and isotonic
solutions to have on a cell? (Where does the water go) - ANSWER-Hypo: water into
cell, cell lysis
Iso: water does not move, remains same
Hyper: water moves out of cell, cell crenation
What effect does a 300 mOsm solution of a non-penetrating solute have on a cell
and how does this differ from the effect of a 300 mOsm solution of a PENETRATING
solute? - ANSWER-Penetrating solutes really get in there and just penetrate into the
cells, thus increasing concentration of solute inside the cell. This happens regardless
of penetrating solute concentration. THUS, water will always rush in and lyse a cell
when a penetrating solute is present. The non penetrating is isotonic, so cell and
solution remain the same.
Will 0.25 Osm NaCl solution lyse, crenate, or remain the same a red blood cell?
What about a 0.25 Osm glucose solution? 0.01 mOsm NH4Cl (penetrating solute)? -
ANSWER-actual osmolarity of NaCl solution is 500 mOsm because 250mOsm Na+
+ 250mOsm Cl- = 500 mOsm total. This will cause the cell to crenate. Glucose
doesnt separate, so it is hypotonic relative to the cell and will cause it to lyse.
Penetrating causes cell to lyse.
Initially there is a higher concentration of sodium on the left side of a beaker of water
than on the right side. The 2 sides of the beaker are separated by a selectively
permeable membrane and that membrane is NOT permeable to the sodium. What is
likely to happen (with regard to movement of ions and/or water) in this beaker? -
REVIEW LAB 1 CSCC QUESTIONS AND
ANSWERS
Does the rate of diffusion change as the concentration gradient changes? -
ANSWER-Yes, as concentration gradient increases, rate of diffusion increases.
How do concentration gradients affect the direction of diffusion? - ANSWER-They
increase rate high to low.
Do solutes of differing masses diffuse at the same rates if concentration gradients
are the same? - ANSWER-No, bigger stuff diffuses slower, smaller stuff diffuses
faster.
If multiple solutes are present and diffusing, do they diffuse independently or do they
influence one another's diffusion? - ANSWER-INDEPENDENTLY
In facilitated diffusion, what determines the rate of diffusion: the concentration
gradient or the number of carriers? - ANSWER-Concentration gradient and number
of carriers BOTH affect rate of diffusion. Bigger gradient and more carriers is faster!
What kinds of osmotic effects do you expect hypotonic, hypertonic, and isotonic
solutions to have on a cell? (Where does the water go) - ANSWER-Hypo: water into
cell, cell lysis
Iso: water does not move, remains same
Hyper: water moves out of cell, cell crenation
What effect does a 300 mOsm solution of a non-penetrating solute have on a cell
and how does this differ from the effect of a 300 mOsm solution of a PENETRATING
solute? - ANSWER-Penetrating solutes really get in there and just penetrate into the
cells, thus increasing concentration of solute inside the cell. This happens regardless
of penetrating solute concentration. THUS, water will always rush in and lyse a cell
when a penetrating solute is present. The non penetrating is isotonic, so cell and
solution remain the same.
Will 0.25 Osm NaCl solution lyse, crenate, or remain the same a red blood cell?
What about a 0.25 Osm glucose solution? 0.01 mOsm NH4Cl (penetrating solute)? -
ANSWER-actual osmolarity of NaCl solution is 500 mOsm because 250mOsm Na+
+ 250mOsm Cl- = 500 mOsm total. This will cause the cell to crenate. Glucose
doesnt separate, so it is hypotonic relative to the cell and will cause it to lyse.
Penetrating causes cell to lyse.
Initially there is a higher concentration of sodium on the left side of a beaker of water
than on the right side. The 2 sides of the beaker are separated by a selectively
permeable membrane and that membrane is NOT permeable to the sodium. What is
likely to happen (with regard to movement of ions and/or water) in this beaker? -
