Which of the following transport mechanisms requires energy?
movement of ion through ion channels
osmosis
diffusion
phagocytosis
facilitated diffusion
answer
phagocytosis
question
Which of the following best defines tonicity?
Tonicity is an indirect measure of the total solute particle concentration of a solution.
Tonicity is the passive movement of water across a biological membrane.
Tonicity is a hypothetical value for the membrane potential at which the electrical driving force is equal and opposite to the chemical driving force, resulting in an electrochemical driving force of zero.
Tonicity is a function of the concentration of impermeant solutes outside the cell relative to inside the cell, and it determines the structural behavior of a cell placed in the solution.
answer
Tonicity is a function of the concentration of impermeant solutes outside the cell relative to inside the cell, and it determines the structural behavior of a cell placed in the solution.
question
Which of the following molecules is LEAST likely to diffuse through the phospholipid bilayer of the plasma membrane?
disaccharide
oxygen
fatty acid
steroids
water
answer
disaccharide
question
Of the four factors which affect the permeability of cell membranes to molecules that cross by simple diffusion, which of the following has the strongest influence on permeability?
temperature
lipid solubility
the presence of appropriate transporters
levels of intracellular ATP storage
answer
lipid solubility
question
Which of the following refers to the number of molecules that cross the membrane in a given length of time?
flux
concentration gradient
permeability
membrane potential
answer
flux
question
In epithelial tissue, the portion of the plasma membrane facing the lumen is called the ________membrane. The portion of the plasma membrane facing the connective tissue/interstitial fluid is called the ________membrane.
epithelial : basement
secretory : attachment
apical : basement
apical : basolateral
luminal : interstitial
answer
apical : basolateral
question
A worker was sitting at her cubicle in the middle of a large room during her lunch break. She began peeling the orange she brought to eat. At first, only she could smell the aroma. But in a matter of minutes, those in the nearby cubicles could also smell it. After several more minutes had passed, nearly everyone in the room could smell the orange. What best explains how so many people could smell one small orange in the middle of a large room?
simple diffusion
osmosis
active transport
facilitated diffusion
answer
simple diffusion
question
What transport process couples the movement of an ion against its electrochemical gradient to another ion that is moving down its electrochemical gradient that was established using cellular energy (ATP)?
primary active transport
secondary active transport
tertiary passive transport
primary passive transport
secondary passive transport
answer
secondary active transport
question
What effect would increasing the extracellular concentration of K+ have on the resting membrane potential (RMP)?
The RMP would become more positive (less negative).
Increasing extracellular K+ will have no effect on the RMP because of the Na+/ K+ pump.
The RMP would become more negative.
Increasing extracellular K+ will have no effect on the RMP because it displaces Na+.
The effects are really seen on the generating potential.
answer
The RMP would become more positive (less negative).
question
T/F- The rate at which molecules are actively transported across a membrane is determined by the rate of transport of individual pumps and the number of pumps in the membrane.
answer
T
question
In which of the following situations would exocytosis be the proper mechanism of membrane transport?
secretion of Na+ from a cell
secretion of water from a cell
secretion of the neurotransmitter serotonin, which is a water-soluble amine molecule
secretion of a steroid hormone from a cell
answer
secretion of the neurotransmitter serotonin, which is a water-soluble amine molecule
question
T/F Primary active transporters are similar to carriers in that they both are able to move ions against their electrochemical gradient.
answer
F
question
The total number of positive charges in our ICF __________.
is equal to the number of negative charges in our ICF
is equal to the number of positive charges in the ECF
is lower than the number of positive charges in our ECF
is greater than the number of positive charges in the ECF
answer
is lower than the number of positive charges in our ECF
question
The transport of two substances across a membrane in the same direction is known as __________.
countertransport
cotransport
antiport
primary active transport
answer
cotransport
question
In general, the molecules that move through specific carrier proteins are determined by which of the following?
the unique fit to binding sites on the channel or carrier protein
the molecule's lipid solubility
the size of a molecule
a water-filled pore
conformational changes in the pore
answer
the unique fit to binding sites on the channel or carrier protein
question
Which of the following statements is true of passive transport of solutes across the plasma membrane?
The direction of movement is determined by the amount of phospholipids in the plasma membrane.
The direction of solute movement is determined by the concentration gradient of the solute.
The energy spent to move the solutes across the plasma membrane is generated through oxidative phosphorylation.
Some kind of membrane-bound protein is necessary for passive transport to take place.
answer
The direction of solute movement is determined by the concentration gradient of the solute.
question
Cystic fibrosis in the black population occurs _____________
at the same frequency as in the Caucasian population.
as a result of a different gene defect than that in the Caucasian population.
not at all.
less frequently.
answer
less frequently.
question
The direct (main) purpose of water transport out of the epithelial cells in the respiratory passages, using the chloride pumps is _____________
to humidify the air that comes into the lungs.
to decrease the stickiness (viscosity) of the mucus, so it does not clog the respiratory passages.
to moisten the top of the respiratory tract epithelial cells so they do not dry out and die.
to cleanse the air passages.
answer
to decrease the stickiness (viscosity) of the mucus, so it does not clog the respiratory passages.
question
Major water movement through a cell membrane generally occurs by movement through _____________
The phospholipid area along the cell membrane.
active transport pump channels for water.
ion channels.
aquaporins.
answer
aquaporins
question
Movement of chloride out of a cell is _____________ its concentration (chemical) and _____________ its electrical (charge) gradient.
with; against
against; with
with; with
against; against
answer
against; with
question
Sodium ions follow chloride by passing through _____________
peripheral proteins in the cell membrane.
ion channels.
aquaporins.
the phospholipid area of the cell membrane.
answer
ion channels.
question
Cystic fibrosis will affect any epithelial cells in the body that _____________
require a chloride pump to facilitate water movement out of epithelial cells.
require chloride to be moved outside a cell to maintain its usual high concentration outside a cell.
require sodium ions to be moved outside a cell.
require water movement outside a cell.
answer
require a chloride pump to facilitate water movement out of epithelial cells.
question
A possible treatment for cystic fibrosis involving the respiratory tract is _____________
to use the Heimlich maneuver, which is the maneuver used when a person aspirates something, like food.
chest physical therapy.
Pushing a hypertonic (high osmotic pressure) saline solution down the respiratory pipe to dislodge the mucus; this would simulate the creation of the osmotic pressure difference, as created by the chloride pump action.
forcing the patient to inhale more deeply.
answer
chest physical therapy.
question
Since a gene is the problem in cystic fibrosis, then the problem involves abnormal formation of _____________
a special transmembrane integral protein.
a cell membrane lipid.
a cell membrane carbohydrate.
a peripheral protein.
answer
a special transmembrane integral protein.
question
The chloride pump in the respiratory epithelial cell is an example of _____________
simple diffusion.
secondary active transport.
facilitated diffusion.
primary active transport.
answer
primary active transport
question
Which of the following ions is found in a higher concentration in the intracellular fluid (ICF) compartment?
K+ (potassium)
Na (sodium)
Cl- (chlorine)
HCO3- (bicarbonate)
answer
K+ (potassium)
question
If a cell's membrane potential (Vm) were equal to +100mV, what would this mean?
The cell would attract negative ions.
Positive ions are lined up along the outside edge of the cell's plasma membrane.
The cell would attract positively charged ions.
The cell's Vm was measured under normal, resting conditions.
answer
The cell would attract negative ions.
question
A primary active transport process is one in which __________.
molecules move through transport proteins that have been activated by ATP
the plasma membrane folds inward to form a vesicle containing extracellular material
molecules pass directly through the phospholipid bilayer of the plasma membrane
an intracellular vesicle fuses with the plasma membrane and releases its contents to the extracellular fluid
molecules move across the plasma membrane without an input of energy
answer
molecules move through transport proteins that have been activated by ATP
question
Some transport processes use transport proteins in the plasma membrane, but do not require ATP. This type of transport is known as _____.
simple diffusion
exocytosis
active transport
facilitated diffusion
endocytosis
answer
facilitated diffusion
question
The majority of water molecules moving across plasma membranes by osmosis do so via a process that is most similar to ____.
cotransport
facilitated diffusion
simple diffusion
active transport
a process that requires energy from the cell
answer
facilitated diffusion
question
The sodium-potassium pump uses ATP to move sodium and potassium ions across the plasma membrane. This statement describes _____.
secondary active transport
facilitated diffusion
simple diffusion
exocytosis
primary active transport
answer
primary active transport
question
A vesicle fuses with the plasma membrane and releases its contents to the extracellular fluid. This statement describes _____.
endocytosis
simple diffusion
facilitated diffusion
exocytosis
active transport
answer
exocytosis
question
The transport of two substances across a membrane in the same direction is known as __________.
countertransport
cotransport
primary active transport
antiport
answer
cotransport
question
If a person sprays air freshener into a room, the fragrance will eventually reach your nose, even in the absence of air currents. Which of the following best describes this process?
facilitated diffusion
primary active transport
flux
simple diffusion
answer
simple diffusion
question
T/F Osmosis occurs through aquaporins.
answer
T
question
Which of the following is found in greater concentration inside the cell than outside?
sodium
potassium
chloride
calcium
water
answer
potassium
question
The flow of water across a biological membrane down its concentration gradient is known as __________.
primary active transport
osmosis
osmolarity
simple diffusion
answer
osmosis
question
The equilibrium potential describes the membrane potential where what two forces are balanced?
chemical and electrical
density and magnetic
chemical and temperature
temperature and density
electrical and permeability
answer
chemical and electrical
question
Both K+ and Na+ ions have a plus one charge, yet it is their relative concentrations that chiefly determine how negative the cells membrane potential will be.
True
False
answer
T
question
At the resting membrane potential, a cell is at equilibrium.
True
False
answer
F
question
The driving force for simple diffusion is moving down its electrochemical gradient.
True
False
answer
T
question
Which of the following is a reflection of the unequal distribution of positive and negative ions across the plasma membrane?
extracellular potential
membrane potential
chemical gradient
electrochemical driving force
chemical driving force
answer
membrane potential
question
Which of the following characteristics of active transport is INCORRECT?
It is not spontaneous.
The direction of the net flux is down the electrochemical gradient.
It requires the input of energy.
It involves a pump.
answer
The direction of the net flux is down the electrochemical gradient.
question
Molecules with a relatively high lipid solubility are capable of crossing the membrane
only through specific protein channels.
through specific lipid channels.
indirectly by moving across a carrier protein.
only with the addition of energy.
directly through the lipid bilayer.
answer
directly through the lipid bilayer.
question
When molecules are passively transported across a membrane, the direction of their movement is dictated by the molecule's tendency to move
out of a cell.
into a cell.
against its concentration gradient.
down its concentration gradient.
in both directions; there is no preference
answer
down its concentration gradient.
question
The chemical force for which of the following ions is directed into the cell?
calcium only
sodium only
potassium only
both potassium and sodium
both sodium and calcium
answer
both sodium and calcium
question
When solute is actively transported across epithelium, what usually follows?
active transport of the solute in the opposite direction
passive transport of the solute in the opposite direction
water movement in the same direction
passive transport of solute in the same direction
water movement in the opposite direction
answer
water movement in the same direction
question
Which of the following characteristics of active transport is INCORRECT?
The direction of the net flux is down the electrochemical gradient.
It involves a pump.
It is not spontaneous.
It requires the input of energy.
answer
The direction of the net flux is down the electrochemical gradient.
question
Based solely upon its electrical charge, the inside of a typical cell will tend to attract extracellular ________ to move inward.
uncharged ions
ions whose concentration gradient allows them
cations
anions
proteins
answer
cations
question
All of the following solutes are found in higher concentration outside of the cell EXCEPT
proteins.
magnesium.
sodium.
chloride.
HCO3-.
answer
proteins
question
Which of the following epithelial membranes is known as the blood-facing membrane?
basement membrane
lysosomal membrane
apical membrane
basolateral membrane
answer
basolateral membrane
question
If the solutions on either side of the membrane have an unequal distribution of charged ions with the inside having an excess of anions, then the inside of the cell would be (negative/positive) relative to the outside.
answer
negative
question
If a molecule crosses a membrane and is quickly removed from the area by the blood stream or some biological pathway, what effect does this have on its rate of diffusion?
Diffusion rate will increase.
Diffusion rate will progressively decrease until zero.
Diffusion rate will remain constant.
Diffusion rate will not be affected.
Diffusion rate will decrease.
answer
Diffusion rate will increase.
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