Microbiology Ch 4

24 July 2022
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question
Which of the active transport types employs diffusion?
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Symport
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What type of transport uses two transport proteins?
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Symport
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Sodium and potassium ions need to be pumped simultaneously against their concentration gradients. Which one of the transport proteins would be most effective at this?
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Antiport
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Why are ATPases associated with active transport proteins?
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They provide transport proteins with the energy needed to pump molecules against their concentration gradients.
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Efflux pumps can be used to pump antibiotics out of a cell once they enter to protect the cell. This will be done against the concentration gradient of the antibiotic. Which of the active transports would most likely be used?
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A Uniport would pump the antibiotic out without needing to bring additional molecules into the cell, and would not allow the antibiotic to diffuse back in.
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Which of the following molecules would be blocked by a cell membrane?
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Ions
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Hydrophobic molecules would enter a cell
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through integral transport proteins.
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What is a hallmark of passive transport across cell membranes?
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It occurs along an electrochemical gradient, and may involve the use of transport proteins.
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A positively charged sodium ion
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would require the use of integral protein channels to pass through a cell membrane.
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Which of the following statements regarding active transport is false?
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It powers the diffusion of water across the cell membrane.
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What makes phospholipid membranes good at keeping some molecules out, and allowing others to freely pass?
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They have both hydrophilic and hydrophobic regions.
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Integral proteins are mostly involved in
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transport function.
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How does water enter and exit a cell?
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By simple diffusion or by use of an integral transport protein
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A glycoprotein
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is a type of peripheral protein above that can be used as a receptor or in enzymatic functions.
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Why is no energy required in passive transport?
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The concentration gradient drives the movement.
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Once equilibrium is reached,
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molecules move, but there is no net movement in a particular direction.
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Which of the following would not move freely across the cytoplasmic membrane?
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Positively charged hydrogen ions
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How is osmosis different from simple diffusion?
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Water movement is driven by the concentration of solutes rather than its own concentration.
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Nonspecific permeases
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allow a variety of molecules to cross the cytoplasmic membrane.
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What will happen to a cell that is placed in a solution containing a high concentration of sugar, a molecule that cannot pass across the cell membrane?
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The cell will lose its interior water, causing it to shrivel up and possibly die.
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How is simple diffusion different from other types of passive transport?
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Simple diffusion does not require a permease.
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Tumbles occur when
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the flagella rotate clockwise.
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Which of the following types of bacterial cells would have only a single flagellum?
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Monotrichous
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Peritrichous bacteria make a run when
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the flagella turn counterclockwise and become bundled.
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Which of the following types of bacterial cells would have flagella located at only one end of the cell?
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Lophotrichous and monotrichous
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What structural part of a bacterial flagellum is composed of flagellin?
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Filament
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How are Gram-positive and Gram-negative flagella different?
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A Gram-positive flagellum has only two rings in its basal body; Gram-negatives each have four.
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The rings
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anchor the flagellum to the cell membrane.
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The basal body is comprised of which structural component(s) of flagella?
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Rod and Rings
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Pathogenic bacteria
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can be identified and classified by differences in their flagellar proteins.
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Which of the following scenarios is an example of bacterial motility?
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A bacterium moving towards a food source
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Axial filaments are found on
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spirochetes.
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How do axial filaments differ from regular bacterial flagella?
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The axial filament is located between the cell membrane and the outer membrane.
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What is the advantage to spirochetes of the corkscrew movement provided by axial filaments?
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It allows the cells to move more easily through viscous human tissues and fluids, such as mucus.
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Axial filaments are composed of
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endoflagella.
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Which of the following molecules is shared by both Gram-positive and Gram-negative organisms?
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N-acetylmuramic acid
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Amoxicillin is an antibiotic that inhibits the formation of peptide cross-links. Amoxicillin, therefore, would most likely inhibit the growth of __________.
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both Gram-positive and Gram-negative organisms
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Porins are present in ______________bacteria because, in these organisms, molecules entering the cell must pass through an extra layer of ___________.
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Gram-negative; membrane
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Which of the following statements about bacterial flagella is true?
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Flagella can rotate 360 degrees.
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Taxis is
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movement towards or away from a stimulus.
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Which of the following terms refers to a bacterium moving towards a light source?
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Positive phototaxis
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As a bacterium approaches a food source, one would expect
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runs to become more frequent.
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Why are receptors on the cell surface necessary for bacterial movement?
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The receptors sense the stimulus and send signals to the flagella.