Medical Microbiology Introduction and Structure Quiz
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Questions and Answers

What is the main function of pili in bacterial cells?

  • Kill spores formed by certain gram-positive rods
  • Mediate attachment of bacteria to the surface of human cells (correct)
  • Facilitate bacterial conjugation
  • Enhance heat resistance in bacteria

    • Which bacteria are known to form highly heat-resistant spores?

  • Mycobacterium tuberculosis
  • Streptococcus pyogenes
  • Bacillus & Clostridium species (correct)
  • Escherichia coli

    • What is the primary purpose of spores in bacterial cells?

  • To mediate attachment to human cells
  • To increase susceptibility to disinfectants
  • To enhance metabolic activity
  • To survive in the soil for extended periods (correct)

    • Which components can be found inside metabolically inactive spores?

    <p>DNA, ribosomes, and other essential components</p> Signup and view all the answers

    How do spores differ from regular bacteria in terms of metabolic activity?

    <p>Spores are metabolically inactive but contain essential components</p> Signup and view all the answers

    What is the primary function of pili in bacterial cells?

    <p>Mediate attachment to human cells</p> Signup and view all the answers

    Why are spores highly heat resistant?

    <p>Possessing a thick, keratinlike coat</p> Signup and view all the answers

    Which bacterial species are known to form spores that can survive for many years in soil?

    <p>Bacillus and Clostridium species</p> Signup and view all the answers

    What is the fate of spores when nutrients become scarce?

    <p>They remain dormant until nutrients are restored</p> Signup and view all the answers

    How do spores differ from regular bacteria in terms of activity during nutrient scarcity?

    <p>Spores remain dormant until conditions improve</p> Signup and view all the answers

    What is the role of pili in bacterial cells?

    <p>Mediate attachment to human cells</p> Signup and view all the answers

    Why are spores able to survive for many years, especially in the soil?

    <p>Presence of a thick, keratinlike coat</p> Signup and view all the answers

    Which bacterial species are known to form spores?

    <p>Bacillus species</p> Signup and view all the answers

    What happens to spores when nutrients are scarce?

    <p>Form bacteria that can cause disease</p> Signup and view all the answers

    What is the primary function of sex pili in bacterial cells?

    <p>Mediate conjugation</p> Signup and view all the answers

    Which group of microorganisms contains organisms that are commonly called parasites?

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

    What is a distinctive feature of eukaryotic cells compared to prokaryotic cells?

    <p>DNA within a nuclear membrane</p> Signup and view all the answers

    Which shape does not belong to the three basic shapes of bacteria?

    <p>Plasmids (circular)</p> Signup and view all the answers

    What is a characteristic feature of prokaryotic bacterial cells?

    <p>Chromosome number varying from one to many</p> Signup and view all the answers

    Which size range best describes most bacteria?

    <p>1 to 3 μm</p> Signup and view all the answers

    Why do Gram-negative bacteria lose the stain in the Gram stain process?

    <p>Because they have a thin peptidoglycan layer covered by an outer lipid-containing membrane</p> Signup and view all the answers

    What enzyme is inhibited by penicillins and cephalosporins in bacterial cells?

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

    Which structure of Gram-negative bacteria regulates the secretion of toxins out of the cell?

    <p>Periplasmic space</p> Signup and view all the answers

    Why do Gram-positive bacteria retain the stain in the Gram stain process?

    <p>Because they have a thick peptidoglycan layer and no outer membrane</p> Signup and view all the answers

    What is the function of pili in bacterial cells?

    <p>Mediate attachment of bacteria to human cells</p> Signup and view all the answers

    What is the main location of beta-lactamases in gram-negative bacteria that degrade certain antibiotics?

    <p>Periplasmic space</p> Signup and view all the answers

    Which statement accurately describes the heat resistance of spores?

    <p>They have a keratinlike coat that contributes to their heat resistance</p> Signup and view all the answers

    What is a unique characteristic of spores when nutrients are scarce?

    <p>They germinate to form bacteria that can cause disease</p> Signup and view all the answers

    Which bacterial species are particularly associated with the formation of spores?

    <p>Bacillus and Clostridium</p> Signup and view all the answers

    How do spores differ from regular bacteria in terms of metabolic activity?

    <p>Spores are metabolically inactive but contain essential components</p> Signup and view all the answers

    What is the primary function of pili in bacterial cells?

    <p>Mediate attachment of bacteria to human cells</p> Signup and view all the answers

    What differentiates spores from regular bacteria when nutrients are scarce?

    <p>They remain metabolically inactive but contain essential components</p> Signup and view all the answers

    Why are spores highly heat resistant?

    <p>Possessing a thick, keratinlike coat</p> Signup and view all the answers

    Which of the following microorganisms is NOT classified as a eukaryote?

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

    What is a distinguishing feature of eukaryotic cells compared to prokaryotic cells?

    <p>Membrane-bound organelles</p> Signup and view all the answers

    Which type of bacteria lacks a cell wall containing peptidoglycan?

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

    What is the characteristic feature of bacteria that are cocci?

    <p>Pairs arrangement (diplococci)</p> Signup and view all the answers

    Which bacterial group is known to have the smallest cells?

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

    What is one of the distinguishing features of eukaryotic DNA compared to prokaryotic DNA?

    <p>'Histones associated with DNA'</p> Signup and view all the answers

    Which bacterial shape is commonly found in clusters when arranged?

    <p>'Clusters (staphylococci)'</p> Signup and view all the answers

    'Helminths' and 'Protozoa' are collectively referred to as what when talking about infectious agents?

    <p>'Protists kingdom'</p> Signup and view all the answers

    'Viruses' differ from other microorganisms in that they:

    <p>'Can replicate only within cells'</p> Signup and view all the answers

    'Bacteria' differ from 'Fungi' in that:

    <p>'They do not contain membrane-bound organelles'</p> Signup and view all the answers

    What sets 'Eukaryotic' cells apart from 'Prokaryotic' cells?

    <p>Membrane-bound organelles as well as the mitotic division.</p> Signup and view all the answers

    What is a common arrangement pattern for 'Cocci' bacteria?

    <p>'Pairs (diplococci)'</p> Signup and view all the answers

    What is the primary function of sex pilus in bacterial cells?

    <p>Function in conjugation</p> Signup and view all the answers

    Why are spores able to survive for many years, especially in the soil?

    <p>They have a thick, keratinlike coat</p> Signup and view all the answers

    Which component is NOT found in metabolically inactive spores?

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

    How do spores differ from regular bacteria during nutrient scarcity?

    <p>They germinate into bacteria causing disease</p> Signup and view all the answers

    What is the main factor contributing to the heat resistance of spores?

    <p>Thick coat</p> Signup and view all the answers

    In bacterial cells, where do sex pili primarily facilitate attachment?

    <p>To other bacteria</p> Signup and view all the answers

    Which statement accurately describes the heat resistance of spores?

    <p>Heat resistance is attributed to their thick coat</p> Signup and view all the answers

    What happens when nutrients are restored to metabolically inactive spores?

    <p>They germinate into active bacteria</p> Signup and view all the answers

    What is the primary role of pili in bacterial cells?

    <p>Facilitate genetic exchange</p> Signup and view all the answers

    Why do spores germinate when nutrients are restored?

    <p>To develop into active bacteria</p> Signup and view all the answers

    What is the distinguishing feature of sex pili compared to other types of pili on bacterial cells?

    <p>They are involved in conjugation</p> Signup and view all the answers

    How do metabolically inactive spores differ from active bacteria?

    <p>Spores lack functioning ribosomes and enzymes</p> Signup and view all the answers

    Why do Gram-positive bacteria retain the stain in the Gram stain process?

    <p>They resist decolorization with acid–alcohol due to high lipid concentration.</p> Signup and view all the answers

    Why do Gram-negative bacteria lose the stain in the Gram stain process?

    <p>They have an outer lipid-containing membrane.</p> Signup and view all the answers

    Which bacterial component is responsible for inhibiting transpeptidase?

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

    Why are mycobacteria considered acid-fast?

    <p>They resist decolorization with acid–alcohol.</p> Signup and view all the answers

    Which bacterial component is located between the inner cell membrane and the outer membrane of gram-negative bacteria?

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

    What is the primary role of the periplasmic space in Gram-negative bacteria?

    <p>Regulating active transport of nutrients into the cell.</p> Signup and view all the answers

    Why are capsules considered important for bacterial survival?

    <p>To limit neutrophil engulfment.</p> Signup and view all the answers

    What is the key characteristic of capsules that makes them antigens in several vaccines?

    <p>Their polysaccharide composition.</p> Signup and view all the answers

    What is the primary function of the 'slime layer' external to bacterial cells?

    <p>To attach bacteria firmly to various surfaces.</p> Signup and view all the answers

    What differentiates plasmids from transposons in bacterial cells?

    <p>Transposons are extrachromosomal circular pieces of DNA.</p> Signup and view all the answers

    Why are lysozymes essential components in bacterial defense mechanisms?

    <p>They kill bacteria by cleaving glycan backbone of peptidoglycan.</p> Signup and view all the answers

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