Bio250 Membrane Questions with
Accurate Solutions
What does it mean when a cell membrane is selectively permeable?
True or false: passive transport uses ATP.
False does NOT require ATP
(diffusion, facilitated diffusion, osmosis)
Describe a concentration gradient.
What is bulk flow?
the movement of a fluid driven by pressure, all substances in that fluid (ex. blood)
travel together
True or false: the interior of a cell is usually electrically negative compared to the outside.
True, resting membrane potential
higher conentration of negative ions inside the cell
Describe the 3 types of passive processes of membrane transport.
diffusion
faciltated diffusion
osmosis
Diffusion is a (dynamic/static) process meaning it (is always moving/can stop when
not needed).
dynamic meaning it is always moving
when eq reached they move back and forth across the membrane
What would a cell look like in the different kinds of solutions? With and without cell
wall Hypotonic, isotonic, and hypertonic
, Without cell wall
a. isotonic- Happy
b. hypertonic (many solutes outside) - shriveled
c. hypotonic (low solutes outside) -nlysis
With cell wall
a. isotonic- flaccid, no movement of water so membrane is not pressed against wall
b. hypertonic- plasmolyzed, water leaves the cell causing membrane to pull away from cell wall
c. hypotonic-turgid, water enters cell making it swell but wall prevents bursting
What is active transport?
Goes against concentration gradient
Low to high
Requires energy
Describe uniport, antiport, and symports.
Symport- molecules in the same direction
Label the symporter and the antiporter.
symport- same direction
antiport- opposite directions
Using this model we can infer that the proton pump (increases/decreases) the pH of the
space outside of the membrane.
decreases the pH
H out of the cell
increase H decreases pH
Secondary active transport example
Na+/glucose cotransporter (SGLTS)
Accurate Solutions
What does it mean when a cell membrane is selectively permeable?
True or false: passive transport uses ATP.
False does NOT require ATP
(diffusion, facilitated diffusion, osmosis)
Describe a concentration gradient.
What is bulk flow?
the movement of a fluid driven by pressure, all substances in that fluid (ex. blood)
travel together
True or false: the interior of a cell is usually electrically negative compared to the outside.
True, resting membrane potential
higher conentration of negative ions inside the cell
Describe the 3 types of passive processes of membrane transport.
diffusion
faciltated diffusion
osmosis
Diffusion is a (dynamic/static) process meaning it (is always moving/can stop when
not needed).
dynamic meaning it is always moving
when eq reached they move back and forth across the membrane
What would a cell look like in the different kinds of solutions? With and without cell
wall Hypotonic, isotonic, and hypertonic
, Without cell wall
a. isotonic- Happy
b. hypertonic (many solutes outside) - shriveled
c. hypotonic (low solutes outside) -nlysis
With cell wall
a. isotonic- flaccid, no movement of water so membrane is not pressed against wall
b. hypertonic- plasmolyzed, water leaves the cell causing membrane to pull away from cell wall
c. hypotonic-turgid, water enters cell making it swell but wall prevents bursting
What is active transport?
Goes against concentration gradient
Low to high
Requires energy
Describe uniport, antiport, and symports.
Symport- molecules in the same direction
Label the symporter and the antiporter.
symport- same direction
antiport- opposite directions
Using this model we can infer that the proton pump (increases/decreases) the pH of the
space outside of the membrane.
decreases the pH
H out of the cell
increase H decreases pH
Secondary active transport example
Na+/glucose cotransporter (SGLTS)
