Cell Biology Quiz: Prokaryotes vs Eukaryotes
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Questions and Answers

Mycoplasma is a non-motile bacterium. Which of the following characteristics confirms that Mycoplasma is a living organism?

  • It lacks certain features commonly associated with motility.
  • It is a small, free-living microbe.
  • It is classified as a bacterium.
  • It can reproduce through binary fission. (correct)

    • Which of the following is a key difference between prokaryotic cells and eukaryotic cells?

  • Prokaryotic cells have a nucleus and eukaryotic cells do not.
  • Prokaryotic cells lack various membrane-bound internal structures, while eukaryotic cells have them. (correct)
  • Prokaryotic cells are typically larger than eukaryotic cells.
  • Prokaryotic cells have a more complex structure than eukaryotic cells.

    • Which of the following is NOT a characteristic of a living organism?

  • Reproduction
  • Growth
  • Motility (correct)
  • Responsiveness

    • Which of the following describes a key difference between prokaryotic and eukaryotic cells?

    <p>Prokaryotic cells lack a nucleus and other membrane-bound organelles, while eukaryotic cells have them. (D)</p> Signup and view all the answers

    What is the typical size of a prokaryotic cell?

    <p>1 micrometer or smaller (B)</p> Signup and view all the answers

    Which of the following processes allows Mycoplasma to obtain energy and nutrients from its environment?

    <p>Metabolism (A)</p> Signup and view all the answers

    The ability to maintain internal stability despite changes in the external environment is known as which of the following?

    <p>Homeostasis (D)</p> Signup and view all the answers

    Which of these is a key characteristic of prokaryotic cells that distinguishes them from eukaryotic cells?

    <p>They lack membrane-bound organelles. (C)</p> Signup and view all the answers

    Based on the information provided, what is the approximate size of a typical eukaryotic cell?

    <p>10 μm - 100 μm (A)</p> Signup and view all the answers

    Which of the following features are present in both prokaryotic and eukaryotic cells?

    <p>Ribosomes (C)</p> Signup and view all the answers

    What is the function of the cell wall in prokaryotic cells?

    <p>Provides structural support and protection. (C)</p> Signup and view all the answers

    Which of the following structures is NOT found in a prokaryotic cell?

    <p>Nucleus (C)</p> Signup and view all the answers

    What is the function of the Golgi body in a eukaryotic cell?

    <p>Modifies, sorts, and packages proteins and lipids. (C)</p> Signup and view all the answers

    Which of the following is NOT a characteristic of eukaryotic cells?

    <p>Lack a cell wall (C)</p> Signup and view all the answers

    What is the primary reason the scientist studying Epulopiscium fishelsoni thought it was eukaryotic?

    <p>It has a more complex structure than typical prokaryotes. (A)</p> Signup and view all the answers

    What is the function of the lysosome in a eukaryotic cell?

    <p>To break down cellular waste products. (C)</p> Signup and view all the answers

    What is the primary function of the cytoskeleton?

    <p>Provides structure and support for the cell (C)</p> Signup and view all the answers

    What are microtubules, microfilaments, and intermediate filaments composed of?

    <p>Proteins (B)</p> Signup and view all the answers

    What is the function of the centrosome in eukaryotic cells?

    <p>Cell division and formation of flagella and cilia (B)</p> Signup and view all the answers

    Which of the following is not a component of the eukaryotic cytoskeleton?

    <p>Centrioles (C)</p> Signup and view all the answers

    What is the difference between the ribosomes of prokaryotes and eukaryotes?

    <p>Prokaryotic ribosomes are smaller than eukaryotic ribosomes (D)</p> Signup and view all the answers

    What is the function of the nuclear envelope?

    <p>Regulation of the movement of molecules between the nucleus and the cytoplasm (A)</p> Signup and view all the answers

    Which of the following is not true about the nucleus of a eukaryotic cell?

    <p>It contains ribosomes for protein synthesis (C)</p> Signup and view all the answers

    What is the significance of the nucleoli within the nucleus?

    <p>They are involved in the synthesis of RNA (A)</p> Signup and view all the answers

    What is the first step in endospore formation?

    <p>DNA is replicated. (A)</p> Signup and view all the answers

    What forms around the endospore during the endospore formation process?

    <p>Spore coat. (A)</p> Signup and view all the answers

    Which substance accumulates within the center of the endospore during its formation?

    <p>Dipicolinic acid. (B)</p> Signup and view all the answers

    What is the significance of the two membranes formed around the forespore?

    <p>They aid in the resistance to heat and chemicals. (A)</p> Signup and view all the answers

    What occurs during the sixth step of endospore formation?

    <p>Endospore matures and spore coat completes. (D)</p> Signup and view all the answers

    Which component is NOT part of the ribosomes discussed?

    <p>Beta subunit. (C)</p> Signup and view all the answers

    How do many antibacterial drugs act on bacterial ribosomes?

    <p>By inhibiting protein synthesis. (D)</p> Signup and view all the answers

    What is the final step in the process of endospore formation?

    <p>Release of endospore from the original cell. (A)</p> Signup and view all the answers

    What distinguishes archaeal ribosomes from those found in bacteria?

    <p>They contain distinct ribosomal proteins. (B)</p> Signup and view all the answers

    Which component is NOT found in the cytoplasm of archaea?

    <p>Linear DNA (A)</p> Signup and view all the answers

    What is a primary function of the glycocalyces in eukaryotic cells?

    <p>To aid in cell recognition and communication. (B)</p> Signup and view all the answers

    Which of the following is a characteristic of all eukaryotic cell membranes?

    <p>Fluid mosaic model of phospholipids and proteins. (B)</p> Signup and view all the answers

    What is a key function of chloroplasts in photosynthetic eukaryotes?

    <p>Produce ATP using light energy (A)</p> Signup and view all the answers

    How many membranes do chloroplasts have?

    <p>Two (A)</p> Signup and view all the answers

    How do the metabolic enzymes of archaea differ from those of bacteria?

    <p>They are involved in RNA synthesis. (A)</p> Signup and view all the answers

    Which component is NOT a function of mitochondria?

    <p>Photosynthesis (B)</p> Signup and view all the answers

    Why are eukaryotic glycocalyces covalently bound to cytoplasmic membranes?

    <p>To facilitate cellular signaling. (A)</p> Signup and view all the answers

    Which statement is true about the cell walls of eukaryotic organisms?

    <p>Fungal cell walls may contain chitin. (D)</p> Signup and view all the answers

    What does the endosymbiotic theory propose about eukaryotic cells?

    <p>Eukaryotic cells originated from a merger of prokaryotes (B)</p> Signup and view all the answers

    What role do membrane rafts play in eukaryotic cytoplasmic membranes?

    <p>They are sites for localized signaling and protein sorting. (D)</p> Signup and view all the answers

    Which statement best describes the relationship between smaller prokaryotes and larger prokaryotes in the endosymbiotic theory?

    <p>Smaller prokaryotes evolved into chloroplasts and mitochondria. (B)</p> Signup and view all the answers

    What effect does colchicine have on cellular functions?

    <p>Inhibits microtubule formation (A)</p> Signup and view all the answers

    What is the primary role of cilia and flagella in eukaryotic cells?

    <p>Cell motility (A)</p> Signup and view all the answers

    Which statement best explains the significance of the phospholipid bilayer in organelles?

    <p>It regulates the movement of substances in and out of organelles. (C)</p> Signup and view all the answers

    Study Notes

    Processes of Life

    • Growth is the increase in size
    • Reproduction is the increase in number
    • Responsiveness is the ability to react to environmental stimuli
    • Metabolism is controlled chemical reactions of organisms

    Characteristics of Life and Their Distribution in Microbes

    • Bacteria, Archaea, and Eukaryotes all show Growth
    • Bacteria, Archaea, and Eukaryotes all show Reproduction
    • Bacteria, Archaea, and Eukaryotes all show Responsiveness
    • Bacteria, Archaea, and Eukaryotes all show Metabolism
    • Viruses display no Growth
    • Viruses use host cells for Reproduction
    • Viruses show some Responsiveness in some viruses
    • Viruses use host cell's Metabolism
    • Viruses lack cytoplasmic membrane or cellular structure
    • All have a membrane-bound structure capable of all of the functions listed above

    Examples of Types of Cells

    • SEM shows bacteria in image (a)
    • LM shows a eukaryote in image (b)
    • The SEM is 1 µm, the LM is 40 µm

    Mycoplasma

    • Mycoplasma can reproduce itself through binary fission, where one cell divides into two daughter cells
    • Mycoplasma has metabolic processes that allow it to obtain energy and nutrients from its environment
    • Mycoplasma maintain internal stability (homeostasis) despite changes in its external environment
    • Mycoplasma can thrive in diverse environments and showcase its adaptation and resilience as a living organism.

    Prokaryotic Cells vs Eukaryotic Cells

    • Prokaryotes include bacteria and archaea
    • Prokaryotes have a simpler structure
    • Prokaryotes lack a nucleus
    • Prokaryotes lack various membrane-bound internal structures
    • Prokaryotes are typically 1.0 µm in diameter or smaller
    • Eukaryotes have a nucleus
    • Eukaryotes have internal membrane-bound organelles
    • Eukaryotes are typically 10–100 µm in diameter
    • Eukaryotes have a more complex structure
    • Eukaryotes include algae, protozoa, fungi, animals, and plants

    Bacterial Cell Walls

    • Provide structure and shape and protect the cell from osmotic forces
    • Assist some cells in attaching to other cells, or in resisting antimicrobial drugs
    • Can target cell walls of bacteria with antibiotics
    • Gives bacterial cells their characteristic shapes
    • Composed of peptidoglycan
    • Scientists describe two basic types: Gram-positive and Gram-negative

    Gram-Positive Bacterial Cell Walls

    • Relatively thick layer of peptidoglycan
    • Contain unique polyalcohols called teichoic acids
    • Appear purple following Gram staining procedure
    • Presence of up to 60% mycolic acid in acid-fast bacteria helps preserve the cell during desiccation

    Gram-Negative Bacterial Cell Walls

    • Thin layer of peptidoglycan
    • Bilayer membrane outside the peptidoglycan contains phospholipids, proteins, and lipopolysaccharide (LPS)
    • Lipid A portion of LPS can cause fever, vasodilation, inflammation, shock, and blood clotting
    • May impede treatment of disease
    • Appear pink following Gram staining procedure

    Bacteria Without Cell Walls

    • Some bacteria lack cell walls
    • Sometimes mistaken for viruses (due to their small size and lack of cell wall)
    • Have other prokaryotic features such as their ribosomes

    Bacterial Cytoplasmic Membranes

    • Structure
    • Referred to as a phospholipid bilayer
    • Composed of lipids and associated proteins
    • Contains integral and peripheral proteins
    • Fluid mosaic model describes current understanding of membrane structure
    • Function
    • Controls substances passing in and out of the cell
    • Stores energy
    • Harvests light energy in photosynthetic bacteria
    • Selectively permeable to most substances
    • Proteins allow substances to cross the membrane
    • Maintains a concentration and electrical gradient

    Membrane Permeability

    • The cell membrane is a semi-permeable membrane
    • Passes only selected components in and out
    • The ease of passage is called permeability, or the rate of passive diffusion

    Passive Transport: Principles of Diffusion

    • Substance from region of high concentration to region of low concentration until equilibrium is met
    • Simple Diffusion: Doesn't require protein helpers. Examples: movement of water, oxygen, carbon dioxide, ethanol, and urea
    • Facilitated Diffusion: Needs protein helpers. Examples: transport of glucose, sodium ions, and potassium ions
    • Osmosis: Spontaneous movement of water molecules from lower solute concentration to higher solute concentration via a semipermeable membrane.

    Active Transport: Principles of Diffusion

    • Substances are moved against concentration gradients using energy, often ATP
    • Uniport is when a molecule is moved in one direction
    • Antiport is when molecules move in opposite directions
    • Coupled transport is when two molecules move in the same direction (symport)

    Group Translocation

    • Active transport in which the substance is chemically altered during transport, typically seen in bacteria

    Cytoplasm of Bacteria

    • Cytosol, the liquid portion mostly water
    • Contains the cell's DNA in the nucleoid region
    • Inclusions are chemical reserve deposits

    Endospores

    • Unique structures produced by some bacteria
    • Defensive strategy for unfavorable conditions
    • Vegetative cells transform into endospores when nutrients are limited
    • Resistance to extreme conditions such as heat, radiation, and chemicals

    Cytoplasm of Prokaryotes

    • Nonmembranous organelles, like ribosomes
    • Ribosomes are for protein synthesis
    • Composed of polypeptides and ribosomal RNA
    • 70S ribosome (30S and 50S)
    • Many antibacterial drugs work on bacterial ribosomes, and won't affect eukaryotes
    • Cytoskeleton
    • Composed of three or four types of protein fibers
    • Can play different roles in the cell, including cell division, cell shape, DNA segregation, and movement

    External Structures of Archaea

    • Glycocalyx - function in the formation of biofilms, adhere to one another and inanimate objects
    • Flagella - consist of basal body, hook, and filament; numerous differences from bacterial flagella
    • Fimbriae and Hami - many archaea have fimbriae and some make fimbria-like structures called hami to attach to surfaces

    Archaeal Cell Walls and Cytoplasmic Membranes

    • Most archaea have cell walls
    • Do not have peptidoglycan
    • Contain variety of specialized polysaccharides and proteins
    • All archaea have cytoplasmic membrane that
    • Maintains electrical and chemical gradients
    • Controls import and export of substances

    Cytoplasm of Archaea

    • Archaeal cytoplasm is similar to bacterial cytoplasm (70S ribosomes, fibrous cytoskeleton, and circular DNA)
    • Archaeal cytoplasm differs from bacterial cytoplasm in ribosomal proteins, metabolic enzymes, and genetic code features more similar to eukaryotes than bacteria

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    Chapter 3: Cell Structure and Function PDF

    Description

    Test your knowledge on the characteristics of living organisms, specifically Mycoplasma, and the key differences between prokaryotic and eukaryotic cells. This quiz covers essential concepts, including cell structures and functions, and their roles in maintaining life. Challenge yourself to understand the fundamentals of cell biology!

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