Microbiology Week 4
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Questions and Answers

What is the primary objective of cleaning in MDRD?

  • To sterilize
  • To disinfect
  • To remove coagulated proteins (correct)
  • To remove waste

    • What is a characteristic of cell life?

  • Production of oxygen
  • Release of energy
  • Excretion of nutrients
  • Reproduction (correct)

    • What is not soluble in water?

  • Carbohydrates
  • Proteins (correct)
  • Water
  • Lipids

    • What is necessary for life to exist?

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

    What is the process of obtaining oxygen and removing carbon dioxide?

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

    What is the process of changing absorbed substances into chemically different forms?

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

    What is the term for the breakdown of food substances into simpler forms?

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

    What is the process of removing waste produced by metabolic reactions?

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

    What is the characteristic shape of Vibrio?

    <p>Comma-shaped</p> Signup and view all the answers

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

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

    What is the primary function of flagella in prokaryotic cells?

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

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

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

    What is the method of cell division in prokaryotic cells?

    <p>Binary fission</p> Signup and view all the answers

    What is the function of ribosomes in prokaryotic cells?

    <p>Protein synthesis</p> Signup and view all the answers

    What is the process by which a small protrusion expands outward from a Mother cell to form a new Daughter cell?

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

    What is the term for the lengthening of a cell as it grows?

    <p>Filamentous growth</p> Signup and view all the answers

    What is the term for the process by which a cell divides into two identical daughter cells?

    <p>Binary fission</p> Signup and view all the answers

    What is the optimal temperature for microbial growth?

    <p>Optimal temperature</p> Signup and view all the answers

    What is the importance of oxygen for aerobic respiration?

    <p>It serves as the terminal electron acceptor</p> Signup and view all the answers

    What is the result of low oxygen levels for microorganisms?

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

    What is the term for the creation of multiple nuclei in a cell?

    <p>Multinucleated cells</p> Signup and view all the answers

    What is the term for the growth of cells in a linear fashion?

    <p>Filamentous growth</p> Signup and view all the answers

    What is the importance of nutrients for microbial growth?

    <p>They are necessary for growth</p> Signup and view all the answers

    What is the result of high temperatures on microbial growth?

    <p>Cell death</p> Signup and view all the answers

    What does the Greek word 'Bacterion' mean?

    <p>Small rod or staff</p> Signup and view all the answers

    Where can bacteria be found?

    <p>In every possible habitat on the planet including soil, water, and toxic and radioactive waste</p> Signup and view all the answers

    How often can bacteria reproduce?

    <p>Every 20 minutes</p> Signup and view all the answers

    What is the characteristic of anaerobic bacteria?

    <p>Cannot tolerate oxygen</p> Signup and view all the answers

    What is the characteristic of facultative anaerobes?

    <p>Can survive in the presence of oxygen and can also survive without oxygen</p> Signup and view all the answers

    What percentage of bacteria are pathogenic?

    <p>Less than 1%</p> Signup and view all the answers

    What did Louis Pasteur's experiment prove?

    <p>Food spoils because of contamination by invisible bacteria</p> Signup and view all the answers

    What is the shape of Streptococcus bacteria?

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

    What type of microorganisms are absolutely dependent upon atmospheric oxygen to survive?

    <p>Obligate aerobes</p> Signup and view all the answers

    Which type of microorganisms grows better in the presence of oxygen, but can still grow without it?

    <p>Facultative anaerobes</p> Signup and view all the answers

    What is the optimal pH range for the growth of most bacteria?

    <p>pH 5.5 - 8.0</p> Signup and view all the answers

    Which type of microorganisms thrive in acidic environments with a pH below 7?

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

    What is the typical pH range for the growth of acidophiles?

    <p>pH 0.0 - 5.5</p> Signup and view all the answers

    What is the name of the bacterium that can cause stomach ulcers and stomach cancer?

    <p>Helicobacter pylori</p> Signup and view all the answers

    What is a common symptom of Helicobacter pylori infection?

    <p>Abdominal pain when the stomach is empty</p> Signup and view all the answers

    Which type of microorganisms cannot tolerate oxygen and will die in its presence?

    <p>Obligate anaerobes</p> Signup and view all the answers

    Study Notes

    Classification of Microorganisms

    • Microorganisms can be classified into six categories: bacteria, viruses, fungi, prions, protozoa, and rickettsia and chlamydia.

    Cell Structure

    • The cell is derived from the Latin word "cellular," meaning small room.
    • It is one of the most basic forms of life and is common to all living things.
    • There are over a million different types of cells, some of which are single-celled and others that function as part of a larger organism.

    Characteristics of Cell Life

    • Cells exhibit characteristics such as movement, responsiveness, growth, circulation, reproduction, respiration, assimilation, digestion, excretion, and absorption.
    • Life depends on five environmental factors: water, food, oxygen, heat, and pressure.
    • Metabolism is the process by which cells obtain, release, and utilize energy.

    Bacteria

    • Bacteria are derived from the Greek word "bacterion," meaning small rod or staff.
    • They are easily adaptable to any living conditions and can be found in every possible habitat on the planet.
    • There are more bacterial cells than human cells in the human body.
    • Bacteria can reproduce every 20 minutes.
    • Not all bacteria are harmful, with less than 1% of bacteria causing disease.
    • Some bacteria are helpful and can produce food, keep soil fertile, aid in digestion, and produce disease-fighting chemicals.

    Germ Theory

    • Louis Pasteur developed the modern germ theory, which states that microorganisms cause disease.
    • Pasteur's experiment proved that food spoils due to contamination by invisible bacteria present in the air, rather than spontaneous generation.

    Bacterial Shapes

    • Bacteria can have different shapes, including:
      • Bacillus (rod-shaped)
      • Coccus (round)
      • Streptococcus (round in chains)
      • Staphylococcus (clustered)
      • Diplococcus (paired)
      • Spirillum (corkscrew-shaped)
      • Vibrio (comma-shaped)

    Cell Structure - Prokaryotic Cell

    • Prokaryotic cells have the following characteristics:
      • No nucleus
      • No membrane-bound organelles (only ribosomes)
      • All are unicellular
      • Smaller and more simple than eukaryotic cells
      • A single, closed circle chromosome contained within the nucleoid
      • Additional circular DNA molecules (plasmids)
      • Cell walls made of peptidoglycan (polymer of NAG and NAM cross-linked with polypeptide chain)
      • Smaller ribosome unit: protein synthesis
      • Divide by binary fission (not mitosis)
      • Flagella: locomotion

    Microbial Growth Methods

    • Microbial growth methods include:
      • Budding (common in yeast)
      • Filamentous growth (common in fungi and some bacteria)
      • Linear growth (in response to chemical stimuli)

    Factors Regulating Growth

    • Factors that regulate microbial growth include:
      • Nutrients
      • Environmental conditions: O2, temperature, pH, osmotic pressure, radiation, and atmospheric pressure
      • Generation time

    Optimal Microbial Temperature

    • The optimal temperature for microbial growth varies depending on the species.
    • At the minimum temperature, the plasma membrane begins to solidify and enzyme function slows.
    • At the maximum temperature, the plasma membrane becomes too fluid and can no longer carry out cellular functions.

    Optimal Microbial Oxygen Concentration

    • The optimal oxygen concentration for microbial growth varies depending on the species.
    • There are four types of oxygen classification for microorganisms:
      • Obligate aerobes
      • Facultative anaerobes
      • Aerotolerant anaerobes
      • Obligate anaerobes

    Optimal Microbial pH Levels

    • The optimal pH level for microbial growth varies depending on the species.
    • Acidophiles grow best at pH 0.0-5.5, neutrophiles at pH 5.5-8.0, and alkalophiles at pH 8.5-11.5.
    • Many bacteria and viruses can survive low pH levels, such as those found in the stomach.

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    Description

    This quiz covers the basics of microbiology, including the classification of microorganisms, bacterial cell structure, identification, and growth. It also touches on the different types of microorganisms.

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