1
CELLULAR AND MOLECULAR BIOLOGY TEST 1 2 3 WITH
VERIFIED CORRECT ANSWERS BEST GRADED AND BEST
SOLUTION 2025 & 2026
describe saturated fatty acids - -answer---no double bonds
-solid at room temp.
-flexible
-cause heart disease
-meats and dairy
describe unsaturated fatty acids - -answer---has at least one double (which forms a bent shape)
-liquid at room temp.
-our bodies should have more of this
-olive oil, corn oil
-monosaturated
-polyunsaturated (multiple bonds)
What is indicated in a patient whom has bilateral cysts on the kidneys? - -answer--cysts are on
both kidneys, so filtration is next to nil. need to worry about dialysis and increased incidences of
cancer of the kidney
What does the cilia of the kidney measure? - -answer--they measure continuous flow from
glomerulus to ureters.
,2
What controls membrane permeability? - -answer--proteins within the membrane
What is the lipid bilayer impermeable to? - -answer--ions and most uncharged polar molecules
What molecules diffuse freely across the membrane? - -answer--small, nonpolar molecules
What is osmosis? - -answer--transfer of water across a semipermeable membrane, not the same
as diffusion
What are the things to consider with osmosis? - -answer--concentration gradient, molecule size,
and permeability of the barrier
What determines the free water concentrations? - -answer--solute concentrations (osmolarity)
What happens in a hypotonic, isotonic, and hypertonic solution with erythrocytes? - -answer--
hypotonic - the cells burst due to water rushing in the cell; isotonic - cell is happy and nothing
changes; hypertonic - cell shrinks
What is characteristic about pumps? - -answer--they move solutes against their concentration
gradient and require energy input to work
What are characteristics about carriers and channels? - -answer--they transport solutes down
their concentration gradient and do not require energy. carriers may move solutes against their
concentration gradient, however.
What is another way to look at open channels? - -answer--they are highly specific passive
transporters
,3
How are channels driven? - -answer--the ions are driven across an electrical and concentration
gradient
What distinguishes a channel from a carrier? - -answer--channels go from open to closed, but
carriers go through a conformational change
What is a primary active transporter? - -answer--any transporter that directly uses ATP to power
it in moving ions against their concentration gradient
In what way do pumps act as a catalyst? - -answer--the presence of a pump greatly enhances
movement of solute against the membrane vs letting it happen spontaneously
In Michaelis-Menten kinetics, as the line approaches Vmax, what is the inference that can be
made? - -answer--as Vmax is approached, the transporters become saturated as they cannot
move the solutes fast enough before another solute is lined up next
What is the role of aquaporins? - -answer--they move water
What is comprised of an aquaporin? - -answer--it is 6.5/7 alpha helices that form into a tubular
protein. each subunit/helix is capable of forming a channel to let water through
What happens to water as it goes through an aquaporin? - -answer--there are ionic molecular
interactions that happen between the water and select asparagines that act as selectivity filters
through the protein.
What happens if a smaller or bigger molecule relative to water tries to go through an
aquaporin? - -answer--a smaller protein doesn't go through because it doesn't form the proper
ionic bonds necessary to move the protein through. bigger proteins simply don't fit
, 4
What is the function of vasopressin? - -answer--it regulates the reuptake of water in the kidney's
collecting duct in the tubule
Where are aquaporins located in the kidney? - -answer--they are located in the collecting duct,
the last part of the glomerulus before the urine runs down the ureter into the bladder for
excretion
How are aquaporins signaled to increase the reuptake of water? - -answer--the posterior
pituitary senses changes in the blood pressure associated with dehydration, so it secretes
ADH/vasopressin to bind to the cells lining the collecting duct on the basolateral membrane.
"things happen" that stimulate the movement of vesicles filled with aquaporins to be
transported to the apical surface of the cell and increase uptake of water
What signals aquaporins to be taken off the apical membrane? - -answer--the loss of the ADH
stimulation on the cell's basolateral surface
What is the difference between the conformation of aquaporins vs ion channels? - -answer--
aquaporins are always open, whereas ion channels may be open or closed, depending on the
concentration of the ion
What is the selectivity of ion channels? - -answer--they are specific to the ion(s) they were made
for
How does potassium interact with its ion channel? - -answer--carbonyl groups in the channel's 4
identical subunits interact with the potassium ion and form a hydration shell
What is a coupled pump? - -answer--a pump in humans that uses ATP
What do animal cells, plant cells, and fungi use H+ pumps for? - -answer--acidify lysosomes and
vacuoles
CELLULAR AND MOLECULAR BIOLOGY TEST 1 2 3 WITH
VERIFIED CORRECT ANSWERS BEST GRADED AND BEST
SOLUTION 2025 & 2026
describe saturated fatty acids - -answer---no double bonds
-solid at room temp.
-flexible
-cause heart disease
-meats and dairy
describe unsaturated fatty acids - -answer---has at least one double (which forms a bent shape)
-liquid at room temp.
-our bodies should have more of this
-olive oil, corn oil
-monosaturated
-polyunsaturated (multiple bonds)
What is indicated in a patient whom has bilateral cysts on the kidneys? - -answer--cysts are on
both kidneys, so filtration is next to nil. need to worry about dialysis and increased incidences of
cancer of the kidney
What does the cilia of the kidney measure? - -answer--they measure continuous flow from
glomerulus to ureters.
,2
What controls membrane permeability? - -answer--proteins within the membrane
What is the lipid bilayer impermeable to? - -answer--ions and most uncharged polar molecules
What molecules diffuse freely across the membrane? - -answer--small, nonpolar molecules
What is osmosis? - -answer--transfer of water across a semipermeable membrane, not the same
as diffusion
What are the things to consider with osmosis? - -answer--concentration gradient, molecule size,
and permeability of the barrier
What determines the free water concentrations? - -answer--solute concentrations (osmolarity)
What happens in a hypotonic, isotonic, and hypertonic solution with erythrocytes? - -answer--
hypotonic - the cells burst due to water rushing in the cell; isotonic - cell is happy and nothing
changes; hypertonic - cell shrinks
What is characteristic about pumps? - -answer--they move solutes against their concentration
gradient and require energy input to work
What are characteristics about carriers and channels? - -answer--they transport solutes down
their concentration gradient and do not require energy. carriers may move solutes against their
concentration gradient, however.
What is another way to look at open channels? - -answer--they are highly specific passive
transporters
,3
How are channels driven? - -answer--the ions are driven across an electrical and concentration
gradient
What distinguishes a channel from a carrier? - -answer--channels go from open to closed, but
carriers go through a conformational change
What is a primary active transporter? - -answer--any transporter that directly uses ATP to power
it in moving ions against their concentration gradient
In what way do pumps act as a catalyst? - -answer--the presence of a pump greatly enhances
movement of solute against the membrane vs letting it happen spontaneously
In Michaelis-Menten kinetics, as the line approaches Vmax, what is the inference that can be
made? - -answer--as Vmax is approached, the transporters become saturated as they cannot
move the solutes fast enough before another solute is lined up next
What is the role of aquaporins? - -answer--they move water
What is comprised of an aquaporin? - -answer--it is 6.5/7 alpha helices that form into a tubular
protein. each subunit/helix is capable of forming a channel to let water through
What happens to water as it goes through an aquaporin? - -answer--there are ionic molecular
interactions that happen between the water and select asparagines that act as selectivity filters
through the protein.
What happens if a smaller or bigger molecule relative to water tries to go through an
aquaporin? - -answer--a smaller protein doesn't go through because it doesn't form the proper
ionic bonds necessary to move the protein through. bigger proteins simply don't fit
, 4
What is the function of vasopressin? - -answer--it regulates the reuptake of water in the kidney's
collecting duct in the tubule
Where are aquaporins located in the kidney? - -answer--they are located in the collecting duct,
the last part of the glomerulus before the urine runs down the ureter into the bladder for
excretion
How are aquaporins signaled to increase the reuptake of water? - -answer--the posterior
pituitary senses changes in the blood pressure associated with dehydration, so it secretes
ADH/vasopressin to bind to the cells lining the collecting duct on the basolateral membrane.
"things happen" that stimulate the movement of vesicles filled with aquaporins to be
transported to the apical surface of the cell and increase uptake of water
What signals aquaporins to be taken off the apical membrane? - -answer--the loss of the ADH
stimulation on the cell's basolateral surface
What is the difference between the conformation of aquaporins vs ion channels? - -answer--
aquaporins are always open, whereas ion channels may be open or closed, depending on the
concentration of the ion
What is the selectivity of ion channels? - -answer--they are specific to the ion(s) they were made
for
How does potassium interact with its ion channel? - -answer--carbonyl groups in the channel's 4
identical subunits interact with the potassium ion and form a hydration shell
What is a coupled pump? - -answer--a pump in humans that uses ATP
What do animal cells, plant cells, and fungi use H+ pumps for? - -answer--acidify lysosomes and
vacuoles
