Ch 4 HW

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.

Diffusion rate will increase.

At the resting membrane potential, a cell is at equilibrium. True False

F

T/F Primary active transporters are similar to carriers in that they both are able to move ions against their electrochemical gradient.

F

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)

K+ (potassium)

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

T

T/F Osmosis occurs through aquaporins.

T

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.

T

The driving force for simple diffusion is moving down its electrochemical gradient. True False

T

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.

The RMP would become more positive (less negative).

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.

The cell would attract negative ions.

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.

The direction of solute movement is determined by the concentration gradient of the solute.

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.

The direction of the net flux is down the electrochemical gradient.

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.

The direction of the net flux is down the electrochemical gradient.

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.

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.

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.

a special transmembrane integral protein.

Movement of chloride out of a cell is _____________ its concentration (chemical) and _____________ its electrical (charge) gradient. with; against against; with with; with against; against

against; with

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

apical : basolateral

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.

aquaporins

Which of the following epithelial membranes is known as the blood-facing membrane? basement membrane lysosomal membrane apical membrane basolateral membrane

basolateral membrane

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

both sodium and calcium

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

cations

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

chemical and electrical

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.

chest physical therapy.

The transport of two substances across a membrane in the same direction is known as __________. countertransport cotransport antiport primary active transport

cotransport

The transport of two substances across a membrane in the same direction is known as __________. countertransport cotransport primary active transport antiport

cotransport

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.

directly through the lipid bilayer.

Which of the following molecules is LEAST likely to diffuse through the phospholipid bilayer of the plasma membrane? disaccharide oxygen fatty acid steroids water

disaccharide

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

down its concentration gradient.

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

exocytosis

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

facilitated diffusion

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

facilitated diffusion

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

flux

Sodium ions follow chloride by passing through _____________ peripheral proteins in the cell membrane. ion channels. aquaporins. the phospholipid area of the cell membrane.

ion channels.

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

is lower than the number of positive charges in our ECF

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.

less frequently.

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

lipid solubility

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

membrane potential

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

molecules move through transport proteins that have been activated by ATP

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.

negative

The flow of water across a biological membrane down its concentration gradient is known as __________. primary active transport osmosis osmolarity simple diffusion

osmosis

Which of the following transport mechanisms requires energy? movement of ion through ion channels osmosis diffusion phagocytosis facilitated diffusion

phagocytosis

Which of the following is found in greater concentration inside the cell than outside? sodium potassium chloride calcium water

potassium

The chloride pump in the respiratory epithelial cell is an example of _____________ simple diffusion. secondary active transport. facilitated diffusion. primary active transport.

primary active transport

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

primary active transport

All of the following solutes are found in higher concentration outside of the cell EXCEPT proteins. magnesium. sodium. chloride. HCO3-.

proteins

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.

require a chloride pump to facilitate water movement out of epithelial cells.

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

secondary active transport

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

secretion of the neurotransmitter serotonin, which is a water-soluble amine molecule

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

simple diffusion

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

simple diffusion

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

the unique fit to binding sites on the channel or carrier protein

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.

to decrease the stickiness (viscosity) of the mucus, so it does not clog the respiratory passages.

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

water movement in the same direction