Prokaryotes vs. Eukaryotes Quiz
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Questions and Answers

What is a distinguishing characteristic of prokaryotes?

  • Associated with histones
  • Single circularly arranged chromosome (correct)
  • DNA enclosed within a membrane
  • Lack cell walls

    • What are the distinguishing characteristics of eukaryotes?

    DNA is in nucleus, multiple chromosomes, associated with histones, has membrane-enclosed organelles, and undergoes mitosis.

    Bacteria range in size from _____ in diameter and ______ in length.

    0.2-2.0 micrometers, 2-8 micrometers

    What are the three possible shapes of bacteria?

    <p>Coccus, Bacillus, Spiral</p> Signup and view all the answers

    Cocci are usually ______ and are elongated and flattened on one side.

    <p>Round</p> Signup and view all the answers

    How do cocci reproduce?

    <p>Divide</p> Signup and view all the answers

    Match the type of cocci with their arrangement after division:

    <p>Pairs = Diplococci Chainlike patterns = Streptococci Groups of four = Tetrads Groups of eight = Sarcinae Clusters = Staphylococci</p> Signup and view all the answers

    How do bacilli appear and divide?

    <p>As single rods and divide only across their short axis</p> Signup and view all the answers

    What do diplobacilli look like after division?

    <p>Appear in pairs</p> Signup and view all the answers

    What is the structure of streptobacilli?

    <p>Occur in chains</p> Signup and view all the answers

    What is the appearance of coccobacilli?

    <p>Oval, look very similar to cocci</p> Signup and view all the answers

    'Bacillus' has how many meanings?

    <p>Two meanings</p> Signup and view all the answers

    What do vibrios look like?

    <p>Curved rods</p> Signup and view all the answers

    What is the shape of spirilla?

    <p>Helical shape</p> Signup and view all the answers

    What is special about spirochetes?

    <p>Helical and flexible</p> Signup and view all the answers

    What are some additional bacterial shapes?

    <p>All of the above</p> Signup and view all the answers

    What determines the shape of bacteria?

    <p>Heredity</p> Signup and view all the answers

    Most bacteria are monomorphic.

    <p>True</p> Signup and view all the answers

    What does it mean for bacteria to be pleomorphic?

    <p>Can have many shapes</p> Signup and view all the answers

    What are the three basic components of a prokaryotic cell?

    <p>Structures external to the cell wall, the cell wall, structures internal to the cell wall</p> Signup and view all the answers

    List some structures external to the cell wall.

    <p>Glycocalyx, Flagella, Axial filaments, Pili, Fimbriae</p> Signup and view all the answers

    Describe the glycocalyx.

    <p>Substance secreted by prokaryotes, viscous, gelatinous polymer composed of polysaccharide or polypeptide.</p> Signup and view all the answers

    What is a capsule?

    <p>Substance organized and firmly attached to the cell wall</p> Signup and view all the answers

    How can the presence of a capsule be detected?

    <p>Negative staining</p> Signup and view all the answers

    What defines a slime layer?

    <p>Unorganized and loosely attached to the cell wall</p> Signup and view all the answers

    Capsules contribute to bacterial virulence by protecting against _____

    <p>Phagocytosis by the cells of the host</p> Signup and view all the answers

    What is glycocalyx important for?

    <p>Biofilms</p> Signup and view all the answers

    What is extracellular polymeric substance?

    <p>Glycocalyx that helps cells in a biofilm attach to their environment and to each other.</p> Signup and view all the answers

    What does glycocalyx protect a cell against?

    <p>Dehydration, prevents nutrients from leaving the cell</p> Signup and view all the answers

    What are flagella?

    <p>Long, filamentous appendages that propel bacteria</p> Signup and view all the answers

    What are bacteria without flagella called?

    <p>Atrichous</p> Signup and view all the answers

    Match the types of flagella with their distribution:

    <p>Peritrichous = Distributed over the entire cell Polar = At one or both poles/ends of cells</p> Signup and view all the answers

    Match polar flagella types:

    <p>Monotrichous = Single flagellum at one pole Lophotrichous = A tuft of flagella from one pole Amphitrichous = Flagella at both poles</p> Signup and view all the answers

    What are the three basic parts of flagella?

    <p>Filament, Hook, Basal Body</p> Signup and view all the answers

    Describe the filament of the flagellum.

    <p>Long, outermost region, constant in diameter, contains globular protein flagella in chains.</p> Signup and view all the answers

    What is the basal body of the flagellum?

    <p>Anchors flagellum to the cell wall and plasma membrane.</p> Signup and view all the answers

    What characterizes the gram-negative basal body?

    <p>Two pairs of rings</p> Signup and view all the answers

    What characterizes the gram-positive basal body?

    <p>Only inner pair is present</p> Signup and view all the answers

    How do flagella move?

    <p>Rotation from the basal body</p> Signup and view all the answers

    What can bacterial cells alter regarding flagella?

    <p>Speed and direction of rotation</p> Signup and view all the answers

    What is motility?

    <p>Ability of an organism to move by itself</p> Signup and view all the answers

    Movement in one direction for any length of time is called _____

    <p>Run or swim</p> Signup and view all the answers

    Runs are interrupted by random changes called _____

    <p>Tumbles</p> Signup and view all the answers

    What causes tumbles?

    <p>Reversal of flagella rotation</p> Signup and view all the answers

    What is taxis?

    <p>The movement of bacterium toward/away from a stimulus</p> Signup and view all the answers

    What are the two types of stimuli that spur taxis?

    <p>Both A and B</p> Signup and view all the answers

    What do motile bacteria have to detect chemical stimuli?

    <p>Receptors</p> Signup and view all the answers

    What are the two types of signals bacteria can receive?

    <p>Both A and B</p> Signup and view all the answers

    What is H antigen?

    <p>Flagellar protein useful for distinguishing among serovars.</p> Signup and view all the answers

    What are axial filaments?

    <p>Structures similar to flagella, enabling movement in spirochetes.</p> Signup and view all the answers

    What do spirochetes exhibit?

    <p>Unique structure and motility</p> Signup and view all the answers

    What type of bacteria have hairlike appendages that are shorter than flagella?

    <p>Gram-negative bacteria</p> Signup and view all the answers

    What is fimbriae?

    <p>Hairlike appendages used for attachment and DNA transfer.</p> Signup and view all the answers

    What are pili?

    <p>Longer than fimbriae, involved in motility and DNA transfer.</p> Signup and view all the answers

    Describe twitching motility.

    <p>Pili extend, make contact with surfaces, then retracts for movement.</p> Signup and view all the answers

    What is gliding motility?

    <p>Smooth, gliding movement of myxobacteria.</p> Signup and view all the answers

    What is the function of the cell wall in bacteria?

    <p>To provide shape and protect the cell from adverse changes.</p> Signup and view all the answers

    What are the typical functions of the cell wall?

    <p>Preventing cells from rupturing due to water pressure.</p> Signup and view all the answers

    The cell wall is composed of what macromolecule?

    <p>Peptidoglycan</p> Signup and view all the answers

    How do peptide cross-bridges interact with cell walls?

    <p>They weaken the cell wall, causing lysis.</p> Signup and view all the answers

    What happens during lysis?

    <p>Rupture of plasma membrane and loss of cytoplasm.</p> Signup and view all the answers

    Describe gram-positive cell walls.

    <p>Many layers of peptidoglycan, thick and rigid structure.</p> Signup and view all the answers

    What are the two classes of teichoic acids?

    <p>Lipoteichoic and wall teichoic</p> Signup and view all the answers

    What do negatively charged teichoic acids do?

    <p>Regulate movement of cations.</p> Signup and view all the answers

    What are teichoic acids involved in?

    <p>Cell growth, preventing wall breakdown, and preventing cell lysis.</p> Signup and view all the answers

    What covers the cell walls of gram-positive streptococci?

    <p>Polysaccharides</p> Signup and view all the answers

    Describe gram-negative cell walls.

    <p>Thin layer of peptidoglycan and an outer membrane.</p> Signup and view all the answers

    What does the outer membrane of gram-negative cell walls contain?

    <p>Lipopolysaccharides (LPS)</p> Signup and view all the answers

    What are the specialized functions of the outer wall?

    <p>Evade phagocytosis, provides barrier to antibiotics and enzymes.</p> Signup and view all the answers

    What makes the outer wall slightly permeable?

    <p>Porins</p> Signup and view all the answers

    What is lipopolysaccharides composed of?

    <p>Lipid A, core polysaccharide, O polysaccharide</p> Signup and view all the answers

    What is Lipid A?

    <p>Lipid portion of LPS, functions as an endotoxin when released.</p> Signup and view all the answers

    What does the core polysaccharide provide?

    <p>Stability</p> Signup and view all the answers

    What role does the O polysaccharide play?

    <p>Functions as an antigen useful for distinguishing gram-negative species.</p> Signup and view all the answers

    What is the Gram stain mechanism based on?

    <p>Differences in the structure of the cell walls of gram-positive and gram-negative bacteria.</p> Signup and view all the answers

    What does crystal violet stain?

    <p>Both gram-positive and gram-negative bacteria purple.</p> Signup and view all the answers

    What does iodine (mordant) do?

    <p>Causes crystals to form.</p> Signup and view all the answers

    What effect does alcohol wash have on gram-positive walls?

    <p>Dehydrates the peptidoglycan, making it impermeable to the crystal violet-iodine.</p> Signup and view all the answers

    What happens to gram-negative bacteria during alcohol wash?

    <p>Dissolves the outer membrane, leaving holes in the peptidoglycan layer.</p> Signup and view all the answers

    What defines atypical cell walls?

    <p>No walls or very little material.</p> Signup and view all the answers

    What do archaea lack in terms of their cell wall?

    <p>Lack walls or have walls that contain polysaccharides/proteins, not peptidoglycan.</p> Signup and view all the answers

    What can enzymatic treatment do to cell walls?

    <p>Can damage cell walls, especially in the presence of lysozyme.</p> Signup and view all the answers

    Describe lysozyme.

    <p>Digestive enzyme that occurs naturally in tears, mucus, and saliva.</p> Signup and view all the answers

    What occurs if lysis does not occur?

    <p>Cell remains surrounded by plasma membrane as a protoplast.</p> Signup and view all the answers

    What can happen to cells in the genus Proteus?

    <p>Can lose their cell walls and swell into irregularly shaped cells.</p> Signup and view all the answers

    What are L forms?

    <p>Cells that can live and divide without cell walls.</p> Signup and view all the answers

    What happens to gram-negative walls when lysozyme is applied?

    <p>Wall is not destroyed to the same extent as gram-positive walls.</p> Signup and view all the answers

    What do protoplasts and spheroplasts undergo in pure water?

    <p>Osmotic lysis.</p> Signup and view all the answers

    Describe the plasma membrane.

    <p>Thin structure enclosing the cytoplasm, primarily phospholipids.</p> Signup and view all the answers

    What is the most important function of the plasma membrane?

    <p>Serve as a selective barrier through which materials enter/exit.</p> Signup and view all the answers

    What includes movement across membranes?

    <p>Both A and B</p> Signup and view all the answers

    What is simple diffusion?

    <p>Net movement of molecules from high to low concentration without energy.</p> Signup and view all the answers

    What is facilitated diffusion?

    <p>Proteins assist in moving ions across membranes without energy.</p> Signup and view all the answers

    What is osmosis?

    <p>Net movement of solvent molecules across a selectively permeable membrane.</p> Signup and view all the answers

    What does osmotic pressure refer to?

    <p>Pressure required to prevent movement of water into a solution.</p> Signup and view all the answers

    What are the three types of osmotic solutions?

    <p>Isotonic, Hypotonic, Hypertonic</p> Signup and view all the answers

    Study Notes

    Prokaryotes vs. Eukaryotes

    • Prokaryotes have DNA in a singular circular chromosome, not enclosed within a membrane, while eukaryotes have multiple chromosomes within a nucleus.
    • Prokaryotic DNA is not associated with histones, whereas eukaryotic DNA is associated with histones and non-histones.
    • Prokaryotes lack membrane-bound organelles; eukaryotes contain organelles such as mitochondria, ER, Golgi complex.
    • Prokaryotic cell walls are primarily made of peptidoglycan, while eukaryotic cell walls, if present, are simpler.
    • Prokaryotes reproduce via binary fission; eukaryotes use mitosis.

    Bacterial Size and Shape

    • Bacteria typically range from 0.2-2.0 micrometers in diameter and 2-8 micrometers in length.
    • Common bacterial shapes include cocci (spherical), bacilli (rod-shaped), and spiral.

    Bacterial Arrangement

    • Cocci can exist as:
      • Diplococci: pairs
      • Streptococci: chains
      • Tetrads: groups of four
      • Sarcinae: groups of eight
      • Staphylococci: clusters
    • Bacilli divide only across their short axis and can form:
      • Diplobacilli: pairs
      • Streptobacilli: chains
      • Coccobacilli: oval shapes resembling cocci.

    Glycocalyx and Its Functions

    • Glycocalyx is a substance secreted by prokaryotes, serving as a biofilm's component; it is viscous and sticky.
    • Encapsulated bacteria are organized and firmly attached, while slime layers are unorganized and loosely attached.
    • Capsules can enhance bacterial virulence and protect pathogenic bacteria from phagocytosis.

    Flagella Structure and Function

    • Flagella are long, filamentous appendages crucial for bacterial movement.
    • There are two types of flagella arrangements: peritrichous (around the entire cell) and polar (at one or both ends).
    • The basic structure of flagella includes a filament, hook, and basal body, with movement achieved through rotation of the basal body.

    Cell Wall Characteristics

    • Prokaryotic cell walls are complex, semirigid structures composed mainly of peptidoglycan.
    • Gram-positive bacteria have thick layers of peptidoglycan, while gram-negative bacteria have a thin layer surrounded by an outer membrane containing lipopolysaccharides (LPS).
    • Peptidoglycan consists of alternating NAM and NAG linked by peptide cross-bridges; this forms a network providing shape and strength to the cell wall.

    Antibiotic Action

    • Penicillin targets the peptidoglycan structure, weakening the cell wall and potentially causing lysis.
    • Lysis is the destruction induced by the rupturing of the plasma membrane, which can lead to cell death.

    Osmotic Responses

    • Protoplasts (gram-positive) and spheroplasts (gram-negative) form when exposure to lysozyme or other agents damages the cell wall.
    • Osmotic lysis occurs when the cell swells due to internal pressure exceeding external pressure, often in dilute solutions.

    Plasma Membrane Role

    • The plasma membrane is a selective barrier that controls the flow of materials in and out of the cell, primarily composed of a phospholipid bilayer.
    • The movement across membranes can occur through passive processes like simple diffusion and facilitated diffusion, as well as osmosis, which specifically involves solvent movement (mostly water).

    Types of Osmotic Solutions

    • Isotonic: equal solute concentration inside and outside the cell.
    • Hypotonic: lower solute concentration outside the cell; may cause cell swelling.
    • Hypertonic: higher solute concentration outside the cell; may lead to cell shrinkage.

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    Description

    Test your knowledge on the differences between prokaryotes and eukaryotes, including their DNA structure, cell organization, and reproductive methods. This quiz also covers bacterial size, shape, and arrangements, providing a comprehensive review of these essential biological concepts.

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