BackDiffusion is important in body fluids, because it tends to
(a) Increase local concentration gradients
(b) Eliminate local concentration gradients
(c) Move substances against concentration gradients
(d) Create concentration gradients
Which molecule most easily diffuses across a biological membrane's lipid bilayer, without help of a protein?
According to the map above, what kind of large molecule transport is also called the process of cell 'eating'?
Match the term with its appropriate definition.
Osmosis
Secondary active transport
Exocytosis
Phagocytosis
Simple diffusion
Primary active transport
Pinocytosis
Facilitated diffusion
a. Type of endocytosis in which a large particle is ingested
b. Transport across the plasma membrane against the concentration gradient via direct use of energy from ATP
c. Passive movement of solute across the plasma membrane
d. Movement of solvent from a solution of lower solute concentration to a solution of higher solute concentration
e. Passive movement of solute across the plasma membrane via a channel or carrier protein
f. Type of endocytosis in which ECF is brought into the cell in a protein-coated pit
g. Release of large substances from the cell through a vesicle
h. Transport of a substance across the plasma membrane against its concentration gradient using the energy from the 'downhill' movement of another substance
Epithelial cells of the kidneys have pumps that drive the transcellular transport of sodium ions.
The movement of sodium ions drives the transcellular transport of water. Explain why water follows sodium. (Connects to Chapter 3)
Osmosis always involves:
a. A selectively permeable membrane
b. A difference in solute concentration
c. Diffusion
d. Active transport
e. a, b, and c
A physiologist observes that the concentration of sodium inside a cell is decidedly lower than that outside the cell. She also observes that there is a small leakage of sodium into the cell. What cellular process prevents the sodium concentration gradient from disappearing?
a. Osmosis
b. Diffusion
c. Primary active transport
d. Secondary active transport
Differentiate between primary and secondary active transport processes.
A 'red-hot' bacterial infection of the intestinal tract irritates the intestinal cells and interferes with digestion. Such a condition is often accompanied by diarrhea, which causes loss of body water. On the basis of what you have learned about osmotic water flows, explain why diarrhea may occur.
Fresh water is a precious natural resource in Florida and it is said that supplies are dwindling. Desalinizing (removing salt from) ocean water has been recommended as a solution to the problem. Why shouldn't we drink salt water?