Circular chromosome, not enclosed within a nuclear envelope; peptidoglycan-containing cell wall; 70S ribosomes; flagella that rotate, composed of flagellin
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Characteristics of Eukaryotic cells:
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Golgi apparatus; linear chromosomes enclosed within a nuclear envelope; 80S ribosome; cellulose or chitin-containing cell wall; flagella that wave, composed of microtubules; endoplasmic reticulum; mitochondria; lysosomes
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Sequence the path of a solute from the external environment to the cytoplasm of a prokaryotic cell:
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Capsule -> Cell wall -> Plasma membrane
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Peptidoglycan in Gram-pos prokaryotic cells:
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Thick layer
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Peptidoglycan in Gram-neg prokaryotic cells:
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Thin layer
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Lipopolysaccharide (LPS):
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Only in Gram-neg cells; in the outer leaflet of the outer membrane; responsible for some of the toxic properties of Gram-neg bacteria
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Teichoic acids:
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Include wall teichoic acids & lipoteichoic acids; only found in Gram-pos cell walls
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Lipoprotein:
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Extends from peptidoglycan into the outer membrane; only found in Gram-neg cell walls
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Outer membrane:
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Lipid bilayer of an inner leaflet (phospholipid) and and outer leaflet (lipopolysaccharide); only found in Gram-neg cell walls
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Select the structures that are found in all bacterial cells:
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Plasma membrane; cytoplasm; ribosomes; nucleoid
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Indicate bacterial structures that are likely to be antigens to which host antibodies bind, marking the invader for phagocytosis:
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Flagella, capsule, fimbriae, cell wall
(Antibodies need to bind to a surface structure)
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Identify antibacterial strategies that would likely be selectively toxic for bacteria:
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Inhibition of peptidoglycan synthesis; interfering with translation at 70S ribosomes; inhibition of fimbriae synthesis (which structures are unique to prokaryotic cells?)
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Pilus:
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Conduit for transfer of DNA from once cell to another
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Capsule:
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Protection from phagocytosis
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Cell Wall:
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Protection of cell from osmotic lysis
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Plasma membrane:
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Location of respiratory enzymes
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Nucleoid:
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Genetic information of the cell
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70S Ribosomes:
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Protein synthesis
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Fimbriae:
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Attachment to other bacteria and to surfaces
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Flagella:
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Motility
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A strain of Steptococcus pneumoniae is no longer able to synthesize its capsular polysaccharide. What is a likely outcome?
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It will be readily phagocytized upon entering the host
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A strain of Neisseria gonorrhoeae has been geneticall altered and can no longer produce fimbriae. What is a likely outcome?
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It will be unable to adhere to host tissue & establish infection
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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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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
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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-pos and Gram-neg flagella different?
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A Gram-pos flagellum has only two rings in its basal body; Gram-neg flagellum 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 components of flagella?
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Rods & 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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Why is ATP necessary for active transport?
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ATP provides energy to transfer material against its concentration gradient
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Which type of active transport protein moves two molecules into the cell at the same time?
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Symport
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Which transport protein employs transporters that move molecules only in one direction?
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Uniport & Symport
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Which molecule shown in the animation, the square or the circle, is moving against its concentration gradient?
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Both the circle and the square
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Which type of active transport protein uses one protein to pump two different molecules?
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Antiport & Symport
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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 & potassium ions need to be pumped simultaneously against their concentration gradients. Which of the transport proteins would be most effective at this?
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Antiport
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Why are ATPases associate 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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Uniport (would pump antibiotic out w/o needing to bring molecules in & wouldn't allow 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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Bacteria that are linked in a chain and stain purple:
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Gram-positive streptococci (chained circles)
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Fimbriae and pili differ in that
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Pili are used for transfer of DNA and motility
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Which of the following is NOT characteristic of the glycocalyx found in bacteria?
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Creates a slimy, slippery coating that prevents bacteria from attaching to surfaces (glycocalyx enables bacteria to attach to surfaces & create biofilms)
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Which eukaryotic organelle is correctly matched with its function?
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Vacuole - storage of materials
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Which of the following is found in the cytoplasm of prokaryotic cells but is ABSENT from the cytoplasm of eukaryotic cells?
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DNA (found in the nucleus of eukaryotes)
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Which of the following statements accurately describes specific bacterial cells walls?
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In Gram-neg bacteria, the thin layer of peptidoglycan is surrounded by an outer membrance made of phospholipids, lipopolysaccharides, and proteins
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Which membrane transport mechanism requires ATP?
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Active transport
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Which type of solution would cause a bacterium with a weak or damaged cell wall to burst as water moves into the cell?
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A hypotonic colution (has a lower solute conc. than the inside of the cell; water should move into the cell causing it to rupture)
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Which is true?
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Endospores allow a cell to survive environmental changes by producing a dormant period with no growth
