Mastering Biology Osmosis and Diffusion

True or false? Osmosis is a type of diffusion.

True (Osmosis is the diffusion of water across a selectively permeable membrane.)

True or false? The water-soluble portion of a phospholipid is the polar head, which generally consists of a glycerol molecule linked to a phosphate group.

True (The hydrophilic, or water-loving, portion of a phospholipid is the polar head, whereas the hydrophobic portion is the nonpolar tail.)

If a red blood cell is placed in a salt solution and bursts, what is the tonicity of the solution relative to the interior of the cell? a) Hypotonic b) Hypertonic c) Osmotic d) Isotonic

a) Hypotonic (The salt concentration in the solution is lower than it is in the cell, so water enters the cell, causing it to burst.)

How can a lipid be distinguished from a sugar? a) Lipids are mostly nonpolar. b) Lipids are mostly saturated. c) A lipid dissolves in water. d) A lipid is made up of only hydrocarbons.

a) Lipids are mostly nonpolar.

Which of the following particles could diffuse easily through a cell membrane? a) Oxygen (O2) b) Hydrogen ion (H+) c) Sodium ion (Na+) d) Glucose

a) Oxygen (O2) (Small nonpolar molecules such as oxygen can diffuse across cell membranes.)

What name is given to the process by which water crosses a selectively permeable membrane? a) osmosis b) diffusion c) pinocytosis d) phagocytosis e) passive transport

a) osmosis (Osmosis is the passive transport of water.)

Which of the following factors does not affect membrane permeability? a) The saturation of hydrocarbon tails in membrane phospholipids b) The polarity of membrane phospholipids c) Temperature d) The amount of cholesterol in the membrane

b) The polarity of membrane phospholipids

What property of dishwashing liquid (detergent) makes it useful to wash grease from pans? a) Hydrophobic nature b) Permeability c) Amphipathic nature d) Solubility in water

c) Amphipathic nature

This cell is in a(n) ____ solution. a) hypotonic b) hypertonic or isotonic c) hypertonic d) hypotonic and isotonic e) isotonic

c) hypertonic

You know that this cell is in a(n) ___ solution because the cell ____. a) isotonic --- neither lost nor gained water b) hypertonic --- lost water c) hypertonic --- gained water d) hypotonic --- swelled e) hypotonic --- shrunk

d) hypotonic --- swelled