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14 Cards in this Set
- Front
- Back
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What evidence suggested to Overton that membranes were composed of lipids?
a) He could see the lipids in the electron microscope. b) Membranes were destroyed by lipid-degrading enzymes. c) He found that the more lipid-soluble a solute was, the more rapidly it would enter root hair cells, while more polar substances would enter the cells more slowly. d) Membranes dissolved in gasoline, but not in water. |
He found that the more lipid-soluble a solute was, the more rapidly it would enter root hair cells, while more polar substances would enter the cells more slowly.
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Membranes contain a wide diversity of lipids, including ________.
a) triglycerides, cholesterol and phosphoglycerides b) cholesterol, phosphoglycerides and sphingolipids c) phosphoglycerides, sphingolipids and triglycerides d) cholesterol, triglycerides and sphingolipids |
cholesterol, phosphoglycerides and sphingolipids
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What is the name of a molecule with the following structure: sphingosine + a fatty acid linked to sphingosine through the sphingosine amino group?
a) a cerebroside b) a ganglioside c) sphingomyelin d) a ceramide |
a ceramide
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What is the name of a molecule with the following structure: sphingosine + a fatty acid + galactose?
a) galactocerebroside b) a ganglioside c) glycolipid d) Both galactocerebroside and glycolipid are correct. |
Both galactocerebroside and glycolipid are correct.
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Which of the following is true about the cholesterol associated with membranes?
a) It makes the cell membrane fluid at room temperature. b) It interferes with the movements of the fatty acid tails of the phospholipids. c) It is oriented with the small hydroxyl group embedded in the lipid bilayer and the remainder of the molecule toward the membrane surface. d) All of these statements are correct. |
It interferes with the movements of the fatty acid tails of the phospholipids.
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Proteins that penetrate the lipid bilayer _________.
a) are called integrated proteins. b) may pass entirely through the lipid bilayer and protrude from both the extracellular and cytoplasmic sides of the membrane. c) are called lipid-anchored proteins. d) All of these statements are correct. |
may pass entirely through the lipid bilayer and protrude from both the extracellular and cytoplasmic sides of the membrane.
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Passive transport includes _________.
a) osmosis. b) facilitated diffusion. c) diffusion of a substance directly across the lipid bilayer of the membrane. d) All of these. |
a) osmosis.
b) facilitated diffusion. c) diffusion of a substance directly across the lipid bilayer of the membrane. d) All of these. |
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How do cells transport small, nonpolar, hydrophobic molecules, such as fatty acids or steroid hormones across the cell membrane?
a) Such molecules diffuse freely. b) Via active transport. c) Via endocytosis. d) None of these choices. |
Such molecules diffuse freely.
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Which part of a neuron conducts impulses toward the cell body?
a) the cell body b) dendrites c) the axon d) the terminal knob |
dendrites
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How do Na+ ions enter a neuron when an action potential is initiated?
a) the Na+/K+-ATPase b) a gated Na+ pump c) a voltage-gated Na+ channel d) a ligand-gated Na+ channel |
a voltage-gated Na+ channel
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Which of the following characteristics affects the diffusion of a substance through the membrane?
a) size b) degree of hydrophobicity c) concentration d) all of these |
a) size
b) degree of hydrophobicity c) concentration d) all of these |
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What would happen to red blood cells placed in an isotonic solution?
a) Cells would lyse. b) Cells would shrink. c) Cells would maintain a constant volume. d) None of these. |
Cells would maintain a constant volume.
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How do Na+ ions enter a neuron when an action potential is initiated?
a) via the Na+/K+-ATPase b) via a gated Na+ pump c) via a gated Na+ channel d) via the Na+/K+- pump |
via a gated Na+ channel
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Tetrahydrocannabinol, the active ingredient in marijuana, binds to receptors located in the ________ terminals of certain brain neurons. It lowers the likelihood that these neurons will release ________.
a) postsynaptic, neurotransmitters b) presynaptic, neurotransmitters c) presynaptic, Ca2+ ions d) dendritic, neurotransmitters |
presynaptic, neurotransmitters
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