Functional Anatomy of Prokaryotic and Eukaryotic Cells
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Questions and Answers

Which characteristic is used to distinguish prokaryotic cells from eukaryotic cells?

  • Presence of circular DNA (correct)
  • Multi-cellular organization
  • Cell membrane structure
  • Size of ribosomes

    • What type of microorganisms are classified under Eukarya?

  • Viruses and bacteria
  • Cyanobacteria and eubacteria
  • Algae and protozoa (correct)
  • Bacteria and Archaea

    • What process allows prokaryotic cells to divide more rapidly?

  • Photosynthesis efficiency
  • Surface area to volume ratio (correct)
  • Utilization of energy from sunlight
  • Presence of histones

    • Which of the following statements accurately describes prokaryotic cells?

    <p>They lack organelles</p> Signup and view all the answers

    Which term describes the collection of cells grown on a nutrient medium?

    <p>Microbial culture</p> Signup and view all the answers

    What characterizes the stationary phase in bacterial growth?

    <p>The number of dying cells equals the number of dividing cells.</p> Signup and view all the answers

    What is true about synchronous growth?

    <p>It allows for observation of individual bacterial growth behaviors.</p> Signup and view all the answers

    How is generation time defined?

    <p>The time required for a cell to double in number.</p> Signup and view all the answers

    What describes the continuous culture?

    <p>It allows constant supply of nutrients and removal of waste.</p> Signup and view all the answers

    What occurs during the death phase of bacterial growth?

    <p>An exponential decrease in living cells.</p> Signup and view all the answers

    What is the primary method for determining viable microbial counts on solid media?

    <p>Spread-plate and Pour-plate methods</p> Signup and view all the answers

    What does CFU stand for in microbial count terminology?

    <p>Colony-forming units</p> Signup and view all the answers

    Which technique involves passing a liquid sample through special membrane filters to determine bacterial numbers?

    <p>Membrane Filter Technique</p> Signup and view all the answers

    In turbidimetric methods, what property of bacterial cultures is primarily measured?

    <p>Light scattering</p> Signup and view all the answers

    What is the role of lipopolysaccharides (LPS) in the outer membrane?

    <p>Functions as an antigen to help evasion of the host's immune system</p> Signup and view all the answers

    Which method directly measures the increase in microbial cell weight as a result of growth?

    <p>Dry Weight Measurement</p> Signup and view all the answers

    Which structure anchors lipopolysaccharide (LPS) to the outer membrane?

    <p>Lipid A</p> Signup and view all the answers

    What specific changes are detected in the growth medium by the measurement of specific chemical changes?

    <p>Acid and gas production</p> Signup and view all the answers

    Which of the following is an acceptable gelling temperature for molten agar before it is added to microbial cultures?

    <p>50°C</p> Signup and view all the answers

    What type of molecules do porins allow to pass through the outer membrane?

    <p>Small molecules</p> Signup and view all the answers

    The term 'viable cell' refers to what characteristic of a microbial cell?

    <p>A cell that is alive and able to grow</p> Signup and view all the answers

    Which of the following is NOT a component of the outer membrane?

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

    What characterizes the cytoplasmic membrane of prokaryotes?

    <p>Use of heptanoids in structural support</p> Signup and view all the answers

    Which of the following best describes the function of the peptidoglycan layer in bacteria?

    <p>It helps in cell division by providing rigidity</p> Signup and view all the answers

    What is a primary function of the cytoplasmic membrane in prokaryotes?

    <p>To allow selective transport of nutrients and ions</p> Signup and view all the answers

    In which type of archaeal cell wall would you find non-sulfated polysaccharides?

    <p>Methanosarcina sp.</p> Signup and view all the answers

    What is one function of motility in prokaryotic cells?

    <p>To allow cells to reach different parts of their environment</p> Signup and view all the answers

    Which of the following describes peritrichous flagellation?

    <p>Flagella inserted around the cell surface</p> Signup and view all the answers

    What structure connects the filament of a flagellum to the flagellum motor?

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

    How do archaella differ from flagella in terms of energy source for rotation?

    <p>They utilize hydrolysis of ATP</p> Signup and view all the answers

    What role do Fli proteins serve in flagella?

    <p>They act as a motor switch to reverse rotation direction</p> Signup and view all the answers

    Which of the following is characterized by a tuft of flagella at one end of a bacterial cell?

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

    What does the cap do in flagellum synthesis?

    <p>Guides flagellin into position</p> Signup and view all the answers

    What is the primary function of cilia in microbial locomotion?

    <p>To facilitate movement and sweep food organisms into the cell</p> Signup and view all the answers

    Which component of the flagellum motor is responsible for generating torque?

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

    What is true about surface motility compared to swimming motility?

    <p>All surface motility is slower than swimming motility</p> Signup and view all the answers

    Which characteristic of flagellin contributes to the construction of the flagellum?

    <p>It contains multiple identical copies</p> Signup and view all the answers

    What type of flagellation has flagella located at both ends of a cell?

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

    What are actin filaments primarily responsible for within a cell?

    <p>Facilitating cytoplasmic streaming</p> Signup and view all the answers

    What determines the speed of movement for methanocaldococcus compared to other cells?

    <p>Diameter of its flagella</p> Signup and view all the answers

    Study Notes

    Functional Anatomy of Prokaryotic and Eukaryotic Cells

    • Eukaryotic organisms include algae, protozoa, and fungi, characterized by the presence of organelles.
    • Microorganisms, or microbes, are single-celled or multicellular entities that thrive in supportive environments and are essential for sustaining life, with roles including oxygen production.
    • Pathogenic microbes are responsible for diseases; examples include bacteria, archaea, and algae.
    • Microbiology studies the dominant life forms on Earth and encompasses microbial cultures, which are cells grown on nutrient media.

    Prokaryotes

    • Prokaryotes evolved first, believed to have appeared with RNA as a primordial molecule.
    • Lacking organelles, prokaryotic cells possess circular DNA and no defined nucleus.
    • Key groups of prokaryotes include archaea, cyanobacteria, and eubacteria.
    • Prokaryotic cell division is rapid due to a higher surface area-to-volume ratio and can involve horizontal gene transfer through conjugation.

    Cell Wall and Outer Membrane Structure

    • Gram-positive bacteria have a thick peptidoglycan layer, appearing dark purple under stain.
    • Unique archaeal cell wall compositions include Methanosarcina sp. with non-sulfated polysaccharides and Halococcus sp. with sulfated walls.
    • The outer membrane contains a phospholipid bilayer, porins for small molecule passage, lipoproteins for stability, and lipopolysaccharides (LPS) which function as antigens and can invoke fever.
    • LPS structure includes O-specific polysaccharide, core polysaccharide, and Lipid A which anchors LPS to the membrane, critical for cell protection and antibiotic resistance.

    Cytoplasmic Membrane Functions

    • Prokaryotic cytoplasmic membrane exhibits selective permeability, facilitating nutrient and ion transport.
    • It consists of a lipid bilayer where the hydrophobic tail comprises fatty acids and a hydrophilic head with phosphate groups.

    Locomotion in Prokaryotes

    • Bacteria exhibit two primary motility methods: swimming and gliding, utilizing flagella or archaella.
    • Taxis describes how cells move toward or away from stimuli.
    • Flagella are rotary machines that allow prokaryotes to propel through liquids; they consist of filament components made of flagellin.

    Flagellar Structure and Function

    • The flagellum features a filament, a hook connecting to the motor, and a motor housed in the cytoplasmic membrane.
    • The motor includes a rotor made of rings and a stator composed of mot proteins that generate torque.
    • Flagellin synthesis occurs from the tip towards the base of the flagellum.

    Archaella

    • Archaella are similar to flagella but specifically found in archaea; they rotate and are powered by ATP hydrolysis rather than proton motive force.
    • These structures enable motility rates, with some archaea capable of swimming swiftly due to their size-related advantages.

    Internal and External Movement

    • Cytoplasmic streaming refers to the internal movement of organelles powered by the cytoskeleton, aiding nutrient distribution.
    • External movement involves specialized organelles; pseudopodia are temporary extensions that assist in motility.
    • Cilia and flagella are used for movement, utilizing ATP for energy.

    Culturing and Growth Measurements

    • The stationary phase occurs when dying cells equal dividing cells, resulting in no net population change.
    • Continuous cultures contrast batch cultures, describing the sustained growth of microbial populations.
    • Viable counts are performed to assess the number of living cells using spread-plate techniques or membrane filtration.

    Measurement Techniques

    • Turbidimetric methods use light blockage to assess bacterial growth in liquid culture.
    • Nitrogen content can indicate bacterial population levels, as protein constitutes a major cell component.
    • Dry weight and specific chemical changes in the growth medium reveal microbial growth through quantifiable metrics.

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    Description

    This quiz focuses on the functional anatomy of prokaryotic and eukaryotic cells, detailing the characteristics of microorganisms. Explore the differences between these two types of cells, the evolution of prokaryotes, and the role of various organelles in eukaryotic cells.

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