5(3) – Flashcards
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Which of the following factors does not affect membrane permeability?
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The polarity of membrane phospholipids
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How can a lipid be distinguished from a sugar?
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Lipids are mostly nonpolar.
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What property of dishwashing liquid (detergent) makes it useful to wash grease from pans?
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Amphipathic nature
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Which of the following particles could diffuse easily through a cell membrane?
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Oxygen (O2)
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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?
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Hypotonic
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Which of the following statements is TRUE with regard to this animation?
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Both sodium and potassium ions are transported against their concentration gradients.
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Which of the following molecular movements is due to diffusion or osmosis?
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When a plant cell is placed in concentrated salt water, water moves out of the cell.
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Which statement is correct?
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The contents of a red blood cell are hypertonic to distilled water.
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Select the correct statement about osmosis.
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Osmosis is the diffusion of water molecules across a selectively permeable membrane.
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Based on the figure given below, which of these experimental treatments would increase the rate of sucrose transport into the cell?
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decreasing extracellular pH
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Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because __________.
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they amplify the original signal manyfold
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Lipid-soluble signaling molecules, such as testosterone, cross the membranes of all cells but affect only target cells because __________.
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intracellular receptors are present only in target cells
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A protein that spans the phospholipid bilayer one or more times is
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a transmembrane protein.
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Which of the following factors would tend to increase membrane fluidity?
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a greater proportion of unsaturated phospholipids
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In what way do the membranes of a eukaryotic cell vary?
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Certain proteins are unique to each kind of membrane.
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The difference between pinocytosis and receptor-mediated endocytosis is that
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pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis offers more selectivity.
