Phospholipids are completely insoluble in water.
	Phospholipids form a single sheet in water.
	Phospholipids form a structure in which the hydrophobic portion faces outward.
	Phospholipids form a selectively permeable structure.
	They are triacylglycerols, which are commonly available in foods.

	The fluid component of the membrane is composed of phospholipids, and the mosaic part is composed of carbohydrates.
	The fluid aspect of the membrane describes its structure at normal temperatures, and the mosaic aspect describes the membrane as the temperature is lowered.
	The mosaic comprises the carbohydrate chains on the inner surface of the membrane.
	The fluid component of the membrane is phospholipid, and the mosaic is protein.
	Only phospholipids are capable of moving in the membrane.

	the coded information in DNA
	thin sections (slices) of fixed and embedded cells
	proteins imbedded in membrane bilayers
	patterns of movement in living cells
	all of the above

	on the outside (external) surface of the membrane
	in the interior of the membrane
	on the inside (cytoplasmic) surface
	in the interior and on the inside surface, but not on the outside surface
	on either surface of the membrane, but not in the interior of the membrane

	enzymatic activity
	cell-cell recognition
	intercellular joining
	cell-cell communication
	all of the above

	Membrane proteins attach the membrane to the cytoskeleton.
	Membrane proteins provide receptors for chemical messengers.
	Membrane proteins form channels, which move substances across the membrane.
	Membrane proteins with short sugar chains form identification tags that are recognized by other cells.
	All of these are functions of membrane proteins.

	Carbohydrates are only found associated with the membranes of prokaryotic cells.
	The carbohydrate composition of most eukaryotic plasma membranes is quite similar.
	Carbohydrates on the plasma membrane are typically short chains of 2–5 monosaccharides.
	Membrane carbohydrates function primarily in cell-cell recognition.
	Carbohydrates associated with the plasma membrane are located on both surfaces of the membrane.

	on the outside (external) surface of the membrane
	in the interior of the membrane
	on the inside (cytoplasmic) surface of the membrane
	on both hydrophilic surfaces of the membrane but not in the hydrophobic interior
	Oligosaccharides are rarely associated with plasma membranes.

	Parts of proteins that are exposed on the cytoplasmic side of the endoplasmic reticulum are also exposed on the cytoplasmic side of the plasma membrane.
	The asymmetrical distribution of membrane proteins, lipids, and carbohydrates across the plasma membrane is determined as the membrane is being constructed.
	Every integral membrane protein has specific orientation in the plasma membrane.
	The first and second answers are correct.
	The first, second, and third answers are all correct.

	carbon dioxide
	glucose
	sodium ion
	DNA
	hemoglobin

	a large polar molecule
	a large nonpolar molecule
	dissolved gases such as oxygen or carbon dioxide
	a small nonpolar molecule
	Any of the above would easily diffuse through the membrane.

	proteins sandwiched between two layers of phospholipid
	proteins embedded in two layers of phospholipid
	a layer of protein coating a layer of phospholipid
	phospholipids sandwiched between two layers of protein
	a phospholipid bilayer with proteins scattered on the surfaces of the membranes

	Passive transport operates independently of diffusion.
	Passive transport operates independently of the concentrations of the substance being transported.
	In passive transport, all movement of the transported molecule stops when its concentration is the same on both sides of the membrane.
	Passive transport does not occur in the human body.
	Passive transport permits the transported molecule to move in either direction, but the majority of transport occurs down the concentration gradient of the molecule.

	A ... the diffusion gradient there is shallower
	A ... its membrane transport proteins will not be saturated
	B ... the diffusion gradient in cell B is steeper
	B ... the oxygen molecules inside cell B have a higher kinetic energy
	B ... the gradient of oxygen is oriented in the opposite direction compared to cell A

	It is very rapid over long distances.
	It requires expenditure of energy by the cell.
	It is a passive process.
	It occurs when molecules move from a region of lower concentration to a region of higher concentration.
	It always requires integral proteins of the cell membrane.

	distilled water
	0.4 M
	0.8 M
	1.0 M
	none of the above

	The added salt would enter the cell, causing the cell to take up water and swell.
	Water would enter the cell by osmosis, and the cell would swell.
	Water would leave the cell by osmosis, causing the volume of the cytoplasm to decrease.
	There would be no osmotic movement of water in response to the added salt.
	The added salt makes the solution hypotonic compared to the cell. Water will enter the cell by osmosis.

	The red blood cell would burst, and the plant cell would shrink.
	Both cells would lose water; the red blood cell would shrivel, and the plant plasma membrane would pull away from the cell wall.
	Seawater is isotonic to both cells. There will be no change in water content of the cells.
	Both cells would gain water by osmosis; the red blood cell would burst, and the plant cell would increase in turgor pressure.
	The red blood cell would shrink, and the plant cell would gain water.

	Facilitated diffusion is another name for osmosis.
	Facilitated diffusion of solutes occurs through phospholipid pores in the membrane.
	Facilitated diffusion requires energy to drive a concentration gradient.
	Facilitated diffusion of solutes may occur through protein pores in the membrane.
	There is only one kind of protein pore for facilitated diffusion.

	a concentration gradient
	a membrane
	a protein
	an outside energy source
	All of the above are components of facilitated diffusion.

	free movement of phospholipids between the two sides of the membrane
	making the phospholipids more unsaturated
	making the phospholipids more saturated
	providing a protein channel for the phospholipid
	None of the above could facilitate movement of phospholipids from one side of the membrane to the other.

	Nothing happens because the two solutions are isotonic to one another.
	Water enters the sucrose solution because the sucrose molecule is a disaccharide and thus larger than the monosaccharide glucose.
	Water leaves the sucrose solution because the sucrose molecule is a disaccharide and thus larger than the monosaccharide glucose.
	The sucrose solution is hypertonic and will gain water because the total mass of sucrose is greater than that of glucose.
	After the sucrose dissociates to two monosaccharides, water will be osmotically drawn to that side of the membrane.

	a hypertonic sucrose solution
	a hypotonic sucrose solution
	a hypertonic urea solution
	a hypotonic urea solution
	pure water

	Bacterial cells shrivel up in high salt solutions, causing the cell to burst.
	High salt concentration lowers the pH, thus inhibiting bacterial metabolism.
	High salt concentration raises the pH, thus inhibiting bacterial metabolism.
	A 30% salt solution is hypotonic to the bacteria, so they gain too much water and burst.
	A 30% salt solution is hypertonic to the bacteria, so they lose too much water and cannot survive.

	For most solutes, active transport most often involves an ATP-powered ion pump and a cotransport protein.
	Active transport uses ATP as its energy source.
	Active transport usually moves solutes down the concentration gradient.
	Active transport requires a protein carrier.
	Proteins involved in active transport are integral membrane proteins.

	simple diffusion
	phagocytosis
	active transport
	exocytosis
	facilitated diffusion

	Active transport involves transport proteins, and facilitated diffusion does not.
	Facilitated diffusion can move solutes against a concentration gradient, and active transport cannot.
	Active transport can move solutes in either direction across a membrane, but facilitated diffusion can only move in one direction.
	Facilitated diffusion involves transport proteins, and active transport does not.
	Active transport requires energy from ATP, and facilitated diffusion does not.

	The sodium-potassium pump transports Na+ and K+ ions across the plasma membrane in opposite directions at the expense of ATP hydrolysis.
	The sodium-potassium pump creates an electrochemical gradient.
	The sodium-potassium pump is electrogenic.
	The sodium-potassium pump causes a pH gradient across the plasma membrane.
	The sodium-potassium pump creates concentration gradients of both Na+ and K+ across the plasma membrane.

	movement of Ca2+ into the cell through an ion channel down its concentration gradient
	passive diffusion of Ca2+ into the cell down its electrochemical gradient
	cotransport of Ca2+ into the cell with Cl- ions
	movement of Ca2+ into the cell through a carrier protein down its electrical gradient
	facilitated diffusion of Ca2+ into the cell down its electrochemical gradient

	pumps sodium out of the cell and potassium into the cell
	creates a voltage difference across the membrane
	can pump a large variety of solutes across a membrane against their concentration gradient
	a cell with an interior that is positively charged relative to the outside of the cell
	a cell with a high internal concentration of protons

	Cotransport involves the hydrolysis of ATP by the transporting protein.
	A cotransport protein is most commonly an ion channel.
	Cotransport proteins allow a single ATP-powered pump to drive the active transport of many different solutes.
	The sodium-potassium pump is an example of a cotransport protein.
	In cotransport, both solutes that are being transported are moving down their chemical gradients.

	Protons cannot move through membrane transport proteins.
	Protons are freely permeable through the phospholipid bilayer, so no transport protein is needed for protons.
	The movement of protons through the cotransport protein cannot occur unless sucrose also moves at the same time.
	In the absence of sucrose, the ATP-powered proton pump does not function, so there is no proton gradient.
	Protons, unlike other substances, do not diffuse down their concentration gradient.

	passive transport
	facilitated diffusion
	osmosis
	receptor-mediated endocytosis
	channel proteins

	endocytosis
	active transport
	receptor-mediated endocytosis
	exocytosis
	flip-flop of phospholipids from one side of the plasma membrane to the other

	osmosis
	passive transport
	exocytosis
	active transport
	endocytosis

	endocytosis
	pinocytosis
	active transport of the neurotransmitter back into the cell
	passive transport (by facilitated diffusion) of the neurotransmitter back into the cell
	receptor-mediated endocytosis

	phagocytosis—secretion of large particles from the cell by fusion of vesicles with the plasma membrane
	exocytosis—the movement of water and solutes out of the cell by vesicle fusion with the plasma membrane
	pinocytosis—the uptake of water and small solutes into the cell by formation of vesicles at the plasma membrane.
	osmosis—passive diffusion of water and small solutes across a membrane
	None of the above are correct matches.