True or False Quiz

Please answer all questions


1	Facilitated diffusion is a mechanism of carrier-mediated transport. (p. 127)
		A)	True
		B)	False


2	Simple diffusion does not require a living cell membrane. (p. 128)
		A)	True
		B)	False


3	Active transport moves solutes from a region of high concentration, through a cell membrane, to a region of low concentration. (p. 127)
		A)	True
		B)	False


4	The spontaneous, random diffusion of molecules creates a concentration gradient. (p. 128)
		A)	True
		B)	False


5	A concentration gradient is a state of low entropy. (p. 128)
		A)	True
		B)	False


6	Movement of a substance down its concentration gradient does not require an energy input. (p. 128)
		A)	True
		B)	False


7	Molecules do not spontaneously diffuse from regions of low concentration to regions of high concentration. (p. 128)
		A)	True
		B)	False


8	The dialysis membranes used in the treatment of kidney disease do not allow plasma protein molecules to pass. (p. 128)
		A)	True
		B)	False


9	Steroid hormones are able to diffuse through phospholipid membranes. (p. 128)
		A)	True
		B)	False


10	Oxygen and carbon dioxide gas molecules can move in and out of cells by simple diffusion. (p. 128)
		A)	True
		B)	False


11	Sodium and potassium ions, being very small, can easily pass through the phospholipid layer of a cell membrane. (p. 128)
		A)	True
		B)	False


12	Diffusion rates through a cell membrane are constant, regardless of the magnitude of the concentration difference between the two sides of the membrane. (p. 129)
		A)	True
		B)	False


13	The permeability of a given cell membrane to a given solute is constant and does not change over the life of the cell. (p. 129)
		A)	True
		B)	False


14	A cell can increase the rate of diffusion of solutes through its membrane by increasing the amount of exposed membrane surface area. (p. 129)
		A)	True
		B)	False


15	Osmosis is the movement of water through a semipermeable membrane from the side with a more dilute solution to the side with a more concentrated solution. (p. 129)
		A)	True
		B)	False


16	To be osmotically active, a solute must be able to pass through a semipermeable membrane. (p. 130)
		A)	True
		B)	False


17	Protein given intravenously would raise a patient's blood volume and pressure. (p. 131)
		A)	True
		B)	False


18	If you calculate the molecular weight of a substance and weigh out precisely that many grams of it, you will always (within statistical error) have the same number of molecules, regardless of what the substance is. (p. 131)
		A)	True
		B)	False


19	One molar (1.0 M) solutions of two different solutes, such as NaCl and glucose, have the same amount of water. (p. 131)
		A)	True
		B)	False


20	One molal (1.0 m) solutions of two different solutes, such as NaCl and glucose, have the same amount of water. (p. 131)
		A)	True
		B)	False


21	One molal (1.0 m) solutions of two different solutes have the same osmotic pressure, regardless of what the solutes are. (p. 132)
		A)	True
		B)	False


22	Osmosis is the net diffusion of water through a semipermeable membrane, so pure water has a higher osmotic pressure than any solution. (p. 130)
		A)	True
		B)	False


23	Calcium chloride (CaCl₂) breaks down in water to Ca²⁺ and 2Cl^-. A calcium chloride solution of 0.33 m, would therefore have the same osmotic pressure as a glucose solution of 1.0 m. (p. 132)
		A)	True
		B)	False


24	Sodium chloride will have a greater osmotic effect than an equivalent molar amount of urea.(p. 132)
		A)	True
		B)	False


25	The osmolality of blood plasma is determined clinically by measuring the molal concentrations of all its solutes and adding these together. (p. 133)
		A)	True
		B)	False


26	A given osmolality will lower the freezing point of a solution the same amount no matter what solutes are in the solution. (p. 133)
		A)	True
		B)	False


27	A 0.3 m glucose solution has twice the osmotic pressure of 0.15 m NaCl solution (p. 132)
		A)	True
		B)	False


28	A solution that is isosmotic to living cells is always isotonic to them. (p. 133)
		A)	True
		B)	False


29	Red blood cells (RBCs) will swell and hemolyze in 0.3 m urea, but not in 0.3 m dextrose. (p. 133)
		A)	True
		B)	False


30	Red blood cells undergo hemolysis if they are placed in a hypertonic solution. (p. 133)
		A)	True
		B)	False


31	Increased stimulation of the osmoreceptors stimulates the sense of thirst. (p. 134)
		A)	True
		B)	False


32	Secretion of antidiuretic hormone (ADH) leads to dilution of the blood. (p. 134)
		A)	True
		B)	False


33	Facilitated diffusion is the only mechanism of passive carrier-mediated transport through cell membranes. (p. 135)
		A)	True
		B)	False


34	Membrane carriers for one solute usually will not transport any other solutes. (p. 135)
		A)	True
		B)	False


35	The rate of membrane transport cannot increase indefinitely as a function of solute concentration. (p. 135)
		A)	True
		B)	False


36	Since membrane transport proteins are specific for the molecules they transport, different solutes do not compete for the same transport protein. (p. 135)
		A)	True
		B)	False


37	Cyanide, a poison that halts the aerobic production of ATP, quickly causes all facilitated diffusion to stop. (p. 136)
		A)	True
		B)	False


38	The rate of facilitated diffusion into a cell depends partly on the amount of the solute present in the extracellular fluid. (p. 136)
		A)	True
		B)	False


39	By means of active transport membrane pumps, most cells maintain intracellular Ca²⁺ concentrations up to 10,000 times higher than the extracellular concentration. (p. 136)
		A)	True
		B)	False


40	Primary active transport requires temporary phosphorylation of the solute molecules being transported through the membrane. (p. 136)
		A)	True
		B)	False


41	The Na⁺/K⁺ pump transports one potassium ion into a cell for each sodium ion it transports out.(p. 137)
		A)	True
		B)	False


42	The Na⁺/K⁺ pumps are found only in nerve and muscle cells. (p. 137)
		A)	True
		B)	False


43	Thyroid hormone, thyroxine, affects the body's metabolic rate by adjusting the activity of Na⁺/K⁺ pumps throughout the body. (p. 137)
		A)	True
		B)	False


44	The Na⁺/K⁺ pumps function for the transport of more than sodium and potassium ions. (p. 137)
		A)	True
		B)	False


45	The membrane potential of a living cell is due to positive ions within the cell that cannot diffuse through the membrane. (p. 139)
		A)	True
		B)	False


46	The living cell membrane is much more permeable to sodium than any other cation. (p. 139)
		A)	True
		B)	False


47	A living cell normally has a relatively high concentration of K⁺ outside the membrane and a low concentration of K⁺ in the cytoplasm. (p. 139)
		A)	True
		B)	False


48	If K⁺ ions were allowed to diffuse freely through the cell membrane, they would eventually reach an equilibrium with equal concentrations of K⁺ both inside and outside the cell. (p. 140)
		A)	True
		B)	False


49	When the K⁺ gates of a cell membrane open, K⁺ rushes into the cell by electrical attraction until it neutralizes the negative charges within the cytoplasm. (p. 140)
		A)	True
		B)	False


50	The term, potential difference, means the amount of electrical charge (voltage) that exists across a cell membrane at any moment. (p. 140)
		A)	True
		B)	False


51	If K⁺ were the only ion that could diffuse through a cell membrane, there would be a membrane potential of -90 mV when potassium ions finally reached an equilibrium. (p. 141)
		A)	True
		B)	False


52	The potassium equilibrium potential (EK) is also the normal resting potential of a cell. (p. 141)
		A)	True
		B)	False


53	Hyperkalemia, perhaps caused by heart or kidney disease, causes the movement of potassium ions that results in the cell membrane potential becoming less negative. (p. 141)
		A)	True
		B)	False


54	The term "resting" used to describe a cell membrane refers to a cell in which the Na⁺ and K⁺ concentrations across the membrane are at equilibrium. (p. 141)
		A)	True
		B)	False


55	The Na⁺/K⁺ pump maintains a stable membrane potential by exchanging one Na⁺ ion for one K⁺ ion in each cycle of transport. (p. 141)
		A)	True
		B)	False

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