Chapter 4

True or false: There is no net flux of solute molecules when a diffusion equilibrium has been reached.

true

What transport process is depicted in the image? Simple diffusion Facilitated diffusion Active transport Phagocytosis

Facilitated Diffusion

Ions are able to cross the cell membrane by ______. Multiple choice question. moving through channel proteins moving directly through the phospholipid bilayer moving through aquaporins

moving through channel proteins

The process of membrane transport in this figure is ______. pinocytosis facilitated diffusion active transport osmosis

Osmosis

Which term best describes the movement of substances that diffuse through the tight junctions that separate luminal fluid and interstitial fluid? Active transport pathway Transcellular pathway Paracellular pathway Facilitated diffusion pathway

Paracellular pathway

Ion channels can usually be in one of two general states (not including inactivation): the____________ state or the _______________state.

open; closed

Ions move across the cell membrane via ______. active transport simple diffusion directly through the lipid bilayer integral membrane proteins changes in their conformation

active transport integral membrane proteins

Primary active transport moves molecules across a membrane (down or against?) a concentration gradient.

against

The movement of water through a semipermeable membrane occurs by what mechanism? Pinocytosis Facilitated diffusion transporter Diffusion through aquaporins Endocytosis Active transporter

Diffusion through aquaporins

The lipid bilayer is more permeable to which type(s) of molecule(s)? hydrophobic water soluble nonpolar hydrophilic lipid soluble polar

hydrophobic nonpolar lipid soluble

Direction of net solute flux crossing a membrane by simple diffusion

high to low concentration

facilitated diffusion

high to low concentration

Explain what happens when normal cells are placed into hypertonic solution.

Cells will shrink.

Explain what happens when normal cells are placed into hypotonic solution.

Cells will swell.

Which two of the following are examples of carrier-mediated membrane transport? Multiple select question. Simple diffusion Exocytosis Facilitated diffusion Active transport Endocytosis

Facilitated diffusion Active transport

Which of the following would increase the time it takes for diffusion equilibrium to be reached between a cell's intracellular fluid and the blood plasma? Increasing the distance between the cell and the blood stream Decreasing the mass of the solute that is diffusing Increasing the surface area of the cell Increasing the temperature of the blood

Increasing the distance between the cell and the blood stream

A solution containing 300 mOsm/L of nonpenetrating solutes and 100 mOsm of penetrating solutes would be classified as which two of the following? Isotonic Hypertonic Hypoosmotic Isoosmotic Hypotonic Hyperosmotic

Isotonic Hyperosmotic

If the concentration gradient for an ion is inward, while the electrical gradient is outward, which direction would indicate the net flux of the ion? Multiple choice question. There will be no net flux. There will be an outward net flux. There will be an inward net flux. It will depend on which force is greater.

It will depend on which force is greater.

Explain what happens when normal cells are placed into isotonic solution.

No changes in cell size.

Ion channels are proteins that can usually be in one of two states. What are the names of the two states? Impermeable Permeable Open Active Passive Closed

Open Closed

What are the two categories of active transport? Multiple select question. Primary Simple Facilitated Secondary

Primary Secondary

Which is a type of membrane transport that directly uses ATP to move a solute against its concentration gradient? Simple diffusion Primary active transport Facilitated diffusion Secondary active transport

Primary active transport

One type of membrane transport protein uses the sodium concentration gradient to move H+ against its concentration gradient in the opposite direction. This is an example of which type of transport? Secondary active transport Facilitated diffusion Primary active transport Simple diffusion

Secondary active transport

Which two of the following are NOT examples of mediated transport? Simple diffusion Facilitated diffusion Osmosis Active transport

Simple diffusion Osmosis

What is the general name for the overall type of transport that moves organic solute X from the lumen side compartment to the blood side compartment in this figure? Transepithelial transport Bulk flow Exocytosis Paracellular transport Simple diffusion

Transepithelial transport

True or false: Diffusion equilibrium between two regions of a solution occurs more rapidly when there is a shorter distance between those regions.

True

Primary active transport and secondary active transport are similar in that they both ______. Multiple select question. can transport a molecule from an area of low concentration to an area of high concentration use a transporter protein exhibit specificity directly require ATP for transport

can transport a molecule from an area of low concentration to an area of high concentration use a transporter protein exhibit specificity

Both ions and water can move across the plasma membrane via _______. channels cotransporter proteins countertransporter proteins carrier proteins

channels

The amount of solute that is crossing a surface in either direction in a given amount of time is known as net _____________________.

flux

Molecules of substances within solids, liquids, and gases are in constant motion, and the source of energy causing this motion is ______. Multiple choice question. electrical heat ATP gravity glucose

heat

Molecules of substances within solids, liquids, and gases are in constant motion, and the source of energy causing this motion is ______. gravity ATP electrical glucose heat

heat

Facilitated diffusion and simple diffusion are similar in that they both ______. use ATP directly to move the solute involve a net flux from higher to lower concentration involve an integral membrane protein through which the solute passes

involve a net flux from higher to lower concentration

A diffusion equilibrium has been reached when the one-way flux ______. occurs in one direction is equal in both directions is greater in one direction

is equal in both directions

The function of the lipid bilayer, in terms of movement of molecules, is to ______ movement of polar substances. limit facilitate

limit

Diffusion of polar molecules into and out of cells and organelles is mainly limited by the ______. concentration gradient lipid bilayer temperature

lipid bilayer

active transport

low to high concentration

Flux is defined as ______. the difference between the amount of material lost in one area and gained in another the amount of material moving in one direction between two compartments in a given period of time the difference between two, one-way fluxes the net amount of material transferred between two locations

the amount of material moving in one direction between two compartments in a given period of time

Primary active transport is characterized by ______. the requirement for ATP movement of molecules against their concentration gradient an absence of carrier proteins

the requirement for ATP movement of molecules against their concentration gradient

Paracellular transport through an epithelial cell layer is the movement of substances ______. Multiple choice question. directly through the cytoplasm of a cell across a membrane in two different directions across a cell in a vesicle through tight junctions between adjacent cells

through tight junctions between adjacent cells

The lipid bilayer functions as a barrier to the passage of ______-soluble molecules. lipid water

water

Will a cell placed into a hypertonic solution change size? Yes, it will swell. No, it will not change size. Yes, it will shrink.

yes, it will shrink

Osmolarity is defined as ______. the movement of water from a dilute to a more concentrated solution the net movement of water through a semipermeable membrane the total number of solute particles in solution one mole of solute particles

Correct Answer the total number of solute particles in solution the movement of water from a dilute to a more concentrated solution Reason: This is osmosis. the net movement of water through a semipermeable membrane the total number of solute particles in solution one mole of solute particles Reason: This is the definition of an osmol.

If the electrical force favoring the movement of an ion into a cell is twice as large as a chemical force favoring the movement of the ion out of the cell, which way will the ion move? There will be no net flux. There will be a net inward flux. There will be a net outward flux.

Correct Answer: There will be a net inward flux. Incorrect: There will be a net outward flux. Reason: The overall (summed) forces acting on the cell favor movement towards the inside of the cell. There will be no net flux.

Liver cells are able to break down glycogen into glucose, thus causing the intracellular glucose concentration to become higher than the extracellular glucose concentration. What happens to facilitated diffusion of glucose under these conditions? Facilitated diffusion of glucose can only be into the cell, so glucose continues to be transported into the cell against its concentration gradient. Facilitated diffusion of glucose stops until the intracellular concentration drops below that of the extracellular fluid. Facilitated diffusion causes net movement of glucose out of the liver cells.

Facilitated diffusion causes net movement of glucose out of the liver cells.

True or false: The energy for simple diffusion comes from ATP.

False

True or False: The permeability of all cells to water is high and constant.

False Incorrect True Reason: The type and number of aquaporins differs in different membranes. In addition, in some cells, the permeability to water can be altered in response to various signals.

Which of the following would increase the time it takes for diffusion equilibrium to be reached between a cell's intracellular fluid and the blood plasma? Multiple choice question. Increasing the temperature of the blood Increasing the distance between the cell and the blood stream Increasing the surface area of the cell Decreasing the mass of the solute that is diffusing

Increasing the distance between the cell and the blood stream

The unit of measure for the total concentration of solute particles (including all different molecular species) in a solution is

Osmolarity

A membrane's permeability to a molecule depends on which of the following? Multiple select question. The lipid solubility of the molecule The surface area of the membrane The concentration gradient of the molecule The molecular weight of the molecule

The lipid solubility of the molecule The molecular weight of the molecule

Which is TRUE about facilitated diffusion across a cell membrane? Net transport by facilitated diffusion can only occur in one direction; if the concentration gradient reverses, transport will stop. In the absence of ATP, facilitated diffusion across a membrane cannot occur. Net transport always occurs from the side with a lower concentration of a substance toward the side with a higher concentration. The net transport by facilitated diffusion will be zero when concentrations of a substance are equal on the two sides of the membrane.

The net transport by facilitated diffusion will be zero when concentrations of a substance are equal on the two sides of the membrane.

If the electrical force favoring the movement of an ion into a cell is twice as large as a chemical force favoring the movement of the ion out of the cell, which way will the ion move? Multiple choice question. There will be a net inward flux. There will be no net flux. There will be a net outward flux.

There will be a net inward flux. _______________________________________________ Incorrect answer: There will be no net flux. Reason: The overall (summed) forces acting on the cell favor movement towards the inside of the cell. There will be a net outward flux. Reason: The overall (summed) forces acting on the cell favor movement towards the inside of the cell.

True or false: The energy for simple diffusion comes from ATP.

True Reason: Simple diffusion does not require ATP. The energy comes from heat which leads to random thermal motion of the molecules.

The key difference between facilitated diffusion and simple diffusion is that facilitated diffusion ______. uses a transporter does not saturate occurs from lower to higher concentration

Uses a transporter

When a substance crosses an epithelial barrier by moving through an epithelial cell, it is said to move via the ______. phagocytotic pathway transcellular pathway paracellular pathway pincocytotic pathway potocytotic pathway

transcellular pathway

The key difference between primary active transport and secondary active transport is that primary active transport ______. uses ATP directly for transport involves an integral membrane protein transports solutes from areas of low concentration to high concentration

uses ATP directly for transport

The key difference between facilitated diffusion and simple diffusion is that facilitated diffusion ______. Multiple choice question. occurs from lower to higher concentration does not saturate uses a transporter

uses a transporter