Microbiology Test Questions Flashcards
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Questions and Answers

Which of the following is a prokaryotic domain in the three-domain system?

  • Fungi
  • Animalia
  • Eukarya
  • Bacteria (correct)

    • Which of the following could be used to sterilize plastic petri plates in a brown paper bag?

  • Microwaves
  • Sunlight
  • Gamma radiation (correct)
  • Ultraviolet radiation
  • None of the above

    • Which of the following is probably true about all the experiments that supposedly proved spontaneous generation?

  • The food source could not support life
  • Microorganisms were already present
  • Too much heat was applied
  • Air was lacking
  • All of the above (correct)

    • The endosymbiotic theory hypothesizes that?

    <p>Eukaryotic cells evolved from prokaryotic cells</p> Signup and view all the answers

    Which of the following eukaryotic organelles most closely resembles a prokaryotic cell?

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

    What is an agent of selection in the evolution of resistance?

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

    Which of the words is used to describe the sum total of DNA in a cell?

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

    To select for streptomycin-resistant bacteria, cells should be grown on media?

    <p>Containing streptomycin, but lacking other antibiotics</p> Signup and view all the answers

    The DNA transfer from a donor cell to a recipient cell during cell contact is called?

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

    Vertical gene transfer occurs when genes are passed?

    <p>From parent to offspring</p> Signup and view all the answers

    Mutations are usually beneficial.

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

    For the evolution of resistance, which of these are required?

    <p>Mutation and selection</p> Signup and view all the answers

    Which of these is not a step in PCR?

    <p>mRNA is copied to form DNA</p> Signup and view all the answers

    Which of these recognizes and cuts specific DNA sequences?

    <p>Restriction enzymes</p> Signup and view all the answers

    One advantage of cDNA libraries over genomic libraries is that the cDNA library?

    <p>Lacks intron sequences</p> Signup and view all the answers

    In the blue-white screening procedure, the purpose of including X-gal in the culture medium is to?

    <p>Distinguish between recombinant and non-recombinant plasmids</p> Signup and view all the answers

    Collections of clones containing random DNA fragments from a whole genome are called?

    <p>Genomic libraries</p> Signup and view all the answers

    The DNA polymerase enzyme, which is produced by a heat-tolerant bacterium, is used in?

    <p>Polymerase chain reaction</p> Signup and view all the answers

    Which of the following is a eukaryotic domain in the three-domain system?

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

    Who was the first to observe microorganisms with a microscope?

    <p>van Leeuwenhoek</p> Signup and view all the answers

    These are the primary molecules making up membranes in cells:

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

    Aerobic respiration differs from anaerobic respiration in which of the following respects?

    <p>The final electron acceptors are different</p> Signup and view all the answers

    Which of the following has to consume carbohydrates for both carbon and energy?

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

    Salts and sugars work to preserve foods by creating a

    <p>Hypertonic environment</p> Signup and view all the answers

    The term facultative anaerobe refers to an organism

    <p>Can use oxygen or can grow without oxygen</p> Signup and view all the answers

    Which group of the following bacterial growth types and temperatures is mismatched?

    <p>Thermophile - optimal growth 37°C</p> Signup and view all the answers

    Which group of microorganisms is most likely to spoil a freshwater trout preserved with salt?

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

    Which of the following is a good method to sterilize the interior of dense materials without using high heat?

    <p>Ionizing radiation</p> Signup and view all the answers

    One important ecosystem function performed by microorganisms (such as algae and cyanobacteria) is the primary production of biomass through the metabolic process of

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

    The bacteria that are typically present and on the surface of the human body, and which are typically harmless or even helpful to humans are called the '________' microbiota.

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

    What does the scientific debate about spontaneous generation vs. biogenesis tell us about the process of science?

    <p>Science is the process of refining ideas through vigorous debate and the challenging of old ideas with new data collection</p> Signup and view all the answers

    Which of the following bacterial genus names means 'string of rod-shaped cells'?

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

    Regarding Pasteur's experiments with the S-neck flask, which of the following statements is true?

    <p>The S-flask allowed air to enter the flask</p> Signup and view all the answers

    Whose work began the 'golden age of microbiology' and included the refinement of aseptic technique?

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

    A single celled, eukaryotic, motile organism that ingests its food and has no cell wall is a

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

    A prokaryote that lacks peptidoglycan in its cell walls and typically lives in extreme environments is called a

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

    What is the typical diameter of bacterial cells?

    <p>0.2-8 microns</p> Signup and view all the answers

    In the name Escherichia coli, Escherichia is the

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

    One way in which fungi and algae differ from bacteria is that bacteria

    <p>Do not have a membrane bound nucleus</p> Signup and view all the answers

    What is the primary function of the bacterial cell wall?

    <p>To protect the cell, especially by preventing osmotic lysis</p> Signup and view all the answers

    What type of bacterium has an extra membrane layer on the outside of the cell wall, which dissolves in alcohol, leaving holes in the peptidoglycan layer and allowing crystal violet-iodine to wash out?

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

    What is the function of eukaryotic cilia and flagella?

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

    If a pharmaceutical drug attacks and destroys peptidoglycan, which type of microorganism would it kill?

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

    If a pharmaceutical drug attacks and destroys chitin, would you expect it to have a significant side effect on humans?

    <p>No</p> Signup and view all the answers

    Mitochondria are the sites of _________ in eukaryotic cells.

    <p>cellular respiration</p> Signup and view all the answers

    Which type of molecule is composed of (CH2O) units?

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

    Enzymes are a type of __________ composed of a string of amino acids.

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

    Which type of reaction absorbs (requires) energy when it occurs?

    <p>Anabolic (synthesis)</p> Signup and view all the answers

    The major energy storage molecule found in all organisms is

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

    What organism is not correctly matched to its energy source?

    <p>Chemoheterotroph - Fe2+</p> Signup and view all the answers

    Which metabolic process produces the fewest ATP molecules?

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

    Which of the following lists the sequence of events during aerobic respiration in the correct order?

    <p>Glycolysis, Krebs, electron transport</p> Signup and view all the answers

    Where in the environment might you find microbes conducting anaerobic respiration?

    <p>In the gut of a cow</p> Signup and view all the answers

    Most bacteria grow best at a pH of approximately

    <p>7</p> Signup and view all the answers

    Most fungi grow best at a pH of approximately

    <p>5.5</p> Signup and view all the answers

    A culture medium consisting of agar, human blood, and beef heart is a

    <p>Complex medium</p> Signup and view all the answers

    Which chemical nutrient is found in ATP, RNA, DNA, and membranes?

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

    Which of the following nutrients is only needed in small amounts by microorganisms?

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

    Which of the following is the best method to sterilize heat-sensitive solutions such as antibiotics?

    <p>Membrane filtration</p> Signup and view all the answers

    Which of the following is NOT true about agar?

    <p>It is consumed by microbes in media</p> Signup and view all the answers

    Which of the following would be the most effective method to sterilize petri plates inside a cardboard box?

    <p>Gamma radiation</p> Signup and view all the answers

    What types of microbial growth medium makes it easy to visually distinguish colonies of specific types of microbes?

    <p>Differential media</p> Signup and view all the answers

    Which of the following methods is most effective at killing microbes?

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

    Which of the following refers to the removal of pathogens and the lowering of microbial numbers, but not the complete destruction of all bacterial life?

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

    Which of the following is important for the effectiveness of an antimicrobial treatment?

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

    Heat kills microbes by

    <p>Denaturing enzymes</p> Signup and view all the answers

    Which microbe is most resistant to being killed?

    <p>Endospores of bacteria</p> Signup and view all the answers

    The major energy storage molecule found in all organisms is

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

    Which of the following is the best definition of fermentation?

    <p>The release of energy from the breakdown of organic molecules without oxygen, using an internally-produced, energy rich organic molecule as the final electron acceptor</p> Signup and view all the answers

    The term obligate anaerobe refers to an organism that

    <p>Is killed by oxygen</p> Signup and view all the answers

    For commercial antimicrobial treatment of canned foods, it is important to kill

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

    A single celled, eukaryotic, motile organism that ingests its food is a

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

    Which of the following is true about penicillin and its discovery?

    <p>Penicillin was discovered by accident, when fungi contaminated bacterial cultures</p> Signup and view all the answers

    Aerobic respiration differs from anaerobic respiration in which of the following respects?

    <p>The final electron acceptors are different</p> Signup and view all the answers

    Some bacteria, such as Clostridium and Bacillus, can form ________, allowing them to resist heat, lack of water, and toxic chemicals.

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

    In the electron transport chain, ATP is generated when

    <p>Protons flow across a membrane</p> Signup and view all the answers

    A multicellular organism that has chitin cell walls and absorbs organic material is a

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

    Which of the following statements is true?

    <p>Viruses cannot reproduce outside of a host cell</p> Signup and view all the answers

    Which type of bacterium has a thick outer layer of peptidoglycan, which dehydrates in alcohol, trapping crystal violet-iodine inside the cell?

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

    A capsule or slime that forms a layer on the outside of bacterial cells, allowing them to stick to surfaces, is called a

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

    Salts and sugars work to preserve foods by creating a

    <p>Hypertonic environment</p> Signup and view all the answers

    Which of the following has to consume carbohydrates for both carbon and energy?

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

    Which of the following is the type of bond between molecules of water, which provides water with some of its most important properties, including surface tension and high heat capacity?

    <p>Hydrogen bonds</p> Signup and view all the answers

    Which microbes are easiest to kill?

    <p>Enveloped viruses</p> Signup and view all the answers

    Which of the following is a eukaryotic domain in the three domain system?

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

    Which of the following organisms reproduces using binary fission?

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

    Which of the following is a prokaryotic domain in the three domain system?

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

    A single-celled organism with a nucleus and chloroplasts is a

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

    Which of the following statements is true?

    <p>Most microbes do not cause disease</p> Signup and view all the answers

    Which of the following is true about fungi?

    <p>All are heterotrophs</p> Signup and view all the answers

    Which of the following did not occur during the Golden Age of Microbiology?

    <p>The discovery of bacteria</p> Signup and view all the answers

    Most microorganisms are not disease-causing.

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

    According to the chemiosmotic mechanism, ATP is generated when

    <p>Protons flow across a membrane from an area of high concentration to an area of low concentration</p> Signup and view all the answers

    Archaeans called extreme halophiles prefer to live in environments with high levels of

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

    Laboratory practices that prevent contamination in the lab are called _________ techniques.

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

    In microscopy, with which objective lens is immersion oil typically used?

    <p>100x</p> Signup and view all the answers

    In which century were microorganisms first observed by humans?

    <p>1600s</p> Signup and view all the answers

    Where in the environment might you find microbes conducting anaerobic respiration?

    <p>In the gut of a cow</p> Signup and view all the answers

    Which of the following describes the swimming movement of a motile microbe toward the light?

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

    A gene is best defined as

    <p>A sequence of nucleotides in DNA that codes for a functional product</p> Signup and view all the answers

    Study Notes

    Eukaryotic and Prokaryotic Domains

    • Eukaryotic domain in the three-domain system: Eukarya.
    • Prokaryotic domains: Bacteria and Archaea.
    • Microorganisms in the eukaryotic domain include Fungi, Algae, and Protozoa.

    Historical Figures in Microbiology

    • Antonie van Leeuwenhoek: First to observe microorganisms with a microscope.
    • Louis Pasteur: Conducted experiments disproving spontaneous generation, developed pasteurization.
    • Robert Koch: Refined aseptic techniques; pivotal in establishing germ theory of disease.

    Microbial Growth and Nutrition

    • Facultative anaerobes can grow with or without oxygen.
    • Chemoheterotrophs require carbohydrates for both carbon and energy.
    • Psychrophiles thrive at low temperatures, while thermophiles prefer warmer environments.

    Cellular Components and Functions

    • Phospholipids make up cell membranes, providing structure and signaling.
    • Mitochondria are sites for cellular respiration in eukaryotic cells.
    • Bacterial cell wall protects against osmotic lysis; differs in gram-positive and gram-negative bacteria.

    Respiratory Pathways

    • Aerobic respiration requires oxygen; anaerobic respiration does not.
    • Final electron acceptors differ: oxygen for aerobic, various substances for anaerobic respiration.

    Enzymatic and Metabolic Processes

    • Enzymes are proteins that facilitate biological reactions by lowering activation energy.
    • Fermentation is energy production without oxygen, using an internally produced organic molecule as the final electron acceptor.

    Sterilization and Growth Media

    • Aseptic techniques prevent contamination in laboratories.
    • Membrane filtration sterilizes heat-sensitive solutions.
    • Differential media help distinguish between types of microbes based on their biochemical characteristics.

    Microbial Resistance and Evolution

    • Endospores are resistant structures formed by some bacteria to survive extreme conditions.
    • Antibiotic use acts as a selection agent encouraging the evolution of resistance in bacteria.

    Important Microbial Characteristics

    • Most bacteria grow best at a neutral pH (~7).
    • Fungi prefer slightly acidic environments (~5.5) for optimal growth.
    • Viruses cannot reproduce outside a host cell and are neither prokaryotic nor eukaryotic.

    Key Nutritional Compounds

    • ATP is the primary energy storage molecule for all organisms.
    • Chitin is a component of fungal cell walls; it differs from bacterial peptidoglycan.
    • Microorganisms utilize various nutrients, with some required only in small amounts (e.g., trace elements).

    Microscopy and Laboratory Techniques

    • Immersion oil is used with 100x objective lenses to improve resolution.
    • Autoclaving is effective for sterilization, while dry heat may not be suitable for all materials.

    Microbial Interactions

    • Normal microbiota are typically harmless or beneficial bacteria associated with humans.
    • Mutualistic relationships can aid in nutrient absorption, while pathogenic organisms can cause disease.

    Modern Microbiology Research

    • The endosymbiotic theory posits eukaryotic cells evolved from engulfed prokaryotic cells.
    • Current microbial research focuses on understanding resistance mechanisms and microbial ecosystems.

    Microbial Evolution Concepts

    • Chemiosmotic mechanism describes ATP generation through proton flow across membranes.
    • Understanding microbial genetics aids in applications such as biotechnology and antibiotic resistance studies.

    These notes provide a comprehensive overview of critical microbiological concepts, historical milestones, and essential characteristics impacting both research and practical applications in the field.### Gene Transfer and Transformation

    • Vertical gene transfer involves the passing of genes from parent to offspring.
    • Horizontal gene transfer methods include conjugation, transformation, and transduction.
    • Transformation involves the uptake of naked DNA by a bacterium.

    Mutations

    • Mutations are generally neutral or harmful, not typically beneficial. The statement regarding mutations being usually beneficial is false.

    Evolution of Resistance

    • The evolution of resistance in organisms requires both mutation and selection.
    • Conjugation and plasmid transfer may aid in resistance but are not solely required.

    PCR (Polymerase Chain Reaction)

    • The process of PCR does not include the copying of mRNA to form DNA; this is a step intrinsic to reverse transcription.
    • Steps in PCR include primer hybridization, DNA synthesis, and heating DNA to form single strands.

    Restriction Enzymes

    • Restriction enzymes recognize and cut specific DNA sequences, essential for various DNA manipulation techniques.

    cDNA Libraries

    • cDNA libraries lack intron sequences, providing a more accurate representation of expressed genes compared to genomic libraries.
    • They are useful for cloning eukaryotic genes as they exclude non-coding regions.

    Blue-White Screening

    • X-gal is included in the culture medium to differentiate between recombinant and non-recombinant plasmids in blue-white screening.
    • This method allows for the selection of successful cloning events by color change.

    Genomic Libraries

    • Genomic libraries contain collections of clones with random DNA fragments from an entire genome.
    • cDNA libraries, while also collections of clones, specifically represent expressed genes.

    DNA Polymerase

    • Heat-tolerant DNA polymerase is predominantly used in the polymerase chain reaction due to its stability at high temperatures during the denaturation phase.

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