Ilsa West
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Microbial Exam 1 Oldies Questions Compilation

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Microbial Exam 1 Oldies Questions Compilation

Microbial Exam 1 Oldies Questions Compilation

Question 1 of 107

1

A substance found in the plasma membrane of eukaryotic cells but not the plasma membrane of most prokaryotic cells is ______.

Select one of the following:

  • cholesterol

  • phospholipids

  • proteins

  • phospholipids and proteins

  • cholesterol, phospholipids, and proteins

Explanation

Question 2 of 107

1

An acidophile is an organism that ____.

Select one of the following:

  • ferments glucose to lactic acid

  • requires organic acids for growth

  • grows at high salt concentrations

  • ferments sugars to acids

  • tolerate exposure to low pH values without being killed

Explanation

Question 3 of 107

1

Bacteria that use O2 for aerobic respiration when it is present, but also grow in its absence by fermenting substrates are called ____.

Select one of the following:

  • obligate aerobes

  • facultative anaerobes

  • microaerophile

  • aerotolerant anaerobes

  • obligate anaerobes

Explanation

Question 4 of 107

1

Bacteria that lack cell walls readily lyse in _____ solution.

Select one of the following:

  • hypotonic

  • hypertonic

  • isotonic

  • hypertonic and hypotonic

  • none of the above

Explanation

Question 5 of 107

1

Bacteria in the logarithmic phase of growth ______.

Select one of the following:

  • double at a constant rate called the generation time

  • increase 10-fold in number with each generation

  • form new cells at the same rate that old cells die

  • - double at a constant rate called the generation time
    - form new cells at the same rate that old cells die

  • none of the above

Explanation

Question 6 of 107

1

Capsules are important virulence factors for bacteria because they ____.

Select one of the following:

  • are antiphagocytic factors

  • can mediate the attachment of bacteria to surfaces (including host surfaces)

  • are endotoxins

  • - are antiphagocytic factors
    - can mediate the attachment of bacteria to surfaces (including host surfaces)

  • - are antiphagocytic factors
    - are endotoxins

Explanation

Question 7 of 107

1

Chains of cocci are called _______.

Select one of the following:

  • streptococci

  • diplococci

  • staphylococci

  • sarcinae

  • coccobacilli

Explanation

Question 8 of 107

1

Ignatz Semmelweis discovered that the incidence of peurperal (childbirth) fever could be lowered dramatically by ______.

Select one of the following:

  • penicillin

  • hand and instrument washing in chlorinated lime

  • prayer

  • having doctors deliver babies instead of midwives

  • none of the above

Explanation

Question 9 of 107

1

In glycolysis, one molecule of glucose is converted into _____.

Select one of the following:

  • CO2 and H2O

  • citrate

  • ethanol and CO2

  • glycogen

  • two molecules of pyruvate

Explanation

Question 10 of 107

1

Media that are specifically designed to grow anaerobic bacteria are called ____ media.

Select one of the following:

  • reducing

  • differential

  • selective

  • chemically defined

  • enrichment

Explanation

Question 11 of 107

1

Microorganisms that grow only at temperatures between -10 and 20 C are called _____.

Select one of the following:

  • thermophiles

  • mesophiles

  • psychrophiles

  • psychrotrophs

  • extreme thermophiles

Explanation

Question 12 of 107

1

Negative stains _______.

Select one of the following:

  • stain the background, not the cell

  • are used to detect capsules

  • stain gram-negative bacteria but not gram-positive bacteria

  • - stain the background, not the cell
    - are used to detect capsules

  • - stain the background, not the cell
    - stain gram-negative bacteria but not gram-positive bacteria

Explanation

Question 13 of 107

1

Siderophores are _______.

Select one of the following:

  • toxic oxygen metabolites that form in cells

  • compounds secreted by bacteria that solubilize ferric ions

  • organic growth factors that have to be added to bacterial media

  • electron transport carriers in bacteria

  • none of the above

Explanation

Question 14 of 107

1

The cell wall component that protects bacteria against lysis by osmotic pressure is _________.

Select one of the following:

  • peptidoglycan

  • teichoic acid

  • lipopolysaccharide

  • phospholipid

  • porins

Explanation

Question 15 of 107

1

The conversion of glucose to lactic acid by oral streptococci and lactobacilli _________.

Select one of the following:

  • produces only 2 molecules of ATP for each molecule of glucose degraded

  • is an important event in the formation of dental caries

  • is an example of fermentation

  • - produces only 2 molecules of ATP for each molecule of glucose degraded
    - is an example of fermentation

  • - produces only 2 molecules of ATP for each molecule of glucose degraded
    - is an important event in the formation of dental caries
    - is an example of fermentation

Explanation

Question 16 of 107

1

The outer membrane of gram-negative bacteria contains ________.

Select one of the following:

  • peptidoglycan

  • lipopolysaccharide

  • porins

  • - lipopolysaccharide
    - porins

  • - peptidoglycan
    - lipopolysaccharide
    - porins

Explanation

Question 17 of 107

1

The primary function of the cytoplasmic membrane in prokaryotes is to ________.

Select one of the following:

  • act as a selective barrier that controls the entry and exit of molecules into the cell

  • protect bacterial cells from osmotic lysis

  • act as an adhesin

  • synthesize proteins

  • none of the above

Explanation

Question 18 of 107

1

The total number of viable bacteria in 1 ml of a broth culture can be determined by ______.

Select one of the following:

  • the streak plate technique

  • a standard plate count

  • a direct microscope count

  • - a standard plate count
    - a direct microscope count

  • - the streak plate technique
    - a standard plate count
    - a direct microscope count

Explanation

Question 19 of 107

1

The degree of relatedness between two microorganisms can best be determined by ________.

Select one of the following:

  • biochemical tests

  • morphological features

  • DNA hybridization

  • differential staining

  • DNA base composition

Explanation

Question 20 of 107

1

The enzyme that converts H2O2 into H2O and O2 is called _____.

Select one of the following:

  • lysozyme

  • superoxide dismutase

  • catalase

  • peroxidase

  • oxygenase

Explanation

Question 21 of 107

1

The newly published Bergey's Manual of Systemic Bacteriology, 2nd Edition classifies prokaryotes into taxonomic units primarily based upon _____.

Select one of the following:

  • morphological criteria

  • biochemical tests

  • rRNA nucleotide sequence

  • - morphological criteria
    - biochemical tests

Explanation

Question 22 of 107

1

The Three Domain System for the classification of microorganisms places _____.

Select one of the following:

  • prokaryotes into two domains called Protista and Bacteria

  • domains over Kingdoms

  • all eukaryotic cells into a single domain called Eukarya

  • - domains over kingdoms
    - all eukaryotic cells into a single domain called Eukarya

  • - prokaryotes into two domains called Protista and Bacteria
    - domains over kingdoms
    - all eukaryotic cells into a single domain called Eukarya

Explanation

Question 23 of 107

1

The transfer of DNA from one bacterium to another by a bacteriophage is called ________.

Select one of the following:

  • conjugation

  • transformation

  • transportation

  • transduction

  • lysogeny

Explanation

Question 24 of 107

1

The pour-plate technique differs from the spread-plate technique (for doing a standard plate count) in that ______.

Select one of the following:

  • serial dilutions are prepared in the pour-plate method but not the spread-plate method

  • colonies form in the agar and on the surface in the pour-plate method, but only on the surface with the spread plate method

  • the bacterial sample is mixed into molten agar in the pour plate method, but are spread over the surface of hardened agar in the spread plate method

  • - colonies form in the agar and on the surface in the pour-plate method, but only on the surface with the spread plate method
    - the bacterial sample is mixed into molten agar in the pour plate method, but are spread over the surface of hardened agar in the spread plate method

  • - serial dilutions are prepared in the pour-plate method but not the spread-plate method
    - colonies form in the agar and on the surface in the pour-plate method, but only on the surface with the spread plate method
    - the bacterial sample is mixed into molten agar in the pour plate method, but are spread over the surface of hardened agar in the spread plate method

Explanation

Question 25 of 107

1

The process of destroying all microbial life forms is called ______.

Select one of the following:

  • sterilization

  • antisepsis

  • disinfection

  • sanitization

  • bacteriostasis

Explanation

Question 26 of 107

1

Which of the following statements about facilitated transport is (are) true?

Select one of the following:

  • it requires ATP or other high energy compound

  • it requires a transporter protein

  • It accumulates substrates to higher concentration inside a cell than outside a cell

  • - it requires a transporter protein
    - It accumulates substrates to higher concentration inside a cell than outside a cell

  • - it requires ATP or other high energy compound
    - it requires a transporter protein
    - It accumulates substrates to higher concentration inside a cell than outside a cell

Explanation

Question 27 of 107

1

Which of the following statements about endospores is FALSE?

Select one of the following:

  • they are reproductive structures

  • they are much more resistant to killing than vegetative cells

  • they can germinate and cause food spoilage or disease

  • Bacillus and Clostridium are the only medically important bacteria to produce endospores

  • they can survive in soil for a hundred years or more

Explanation

Question 28 of 107

1

Which of the following statements about eukaryotic ribosomes is (are) true?

Select one of the following:

  • they are smaller than prokaryotic ribosomes

  • they can bind to the endoplasmic reticulum

  • they are the sites of oxidative phosphorylation in eukaryotic cells

  • - they are smaller than prokaryotic ribosomes
    - they can bind to the endoplasmic reticulum

  • - they are smaller than prokaryotic ribosomes
    - they are the sites of oxidative phosphorylation in eukaryotic cells

Explanation

Question 29 of 107

1

Which of the following statements best explains why gram-negative bacteria are more resistant than gram-positive bacteria to most antibiotics and detergents?

Select one of the following:

  • gram-negative bacteria have less peptidoglycan in their cell wall

  • gram-positive bacteria have teichoic acids in their cell wall

  • antibiotics and detergents often have difficulty penetrating the outer membrane of gram-negative bacteria

  • gram-negative bacteria have a different cytoplasmic membrane structure

  • none of the above

Explanation

Question 30 of 107

1

Which of the following statements about eukaryotic cells is FALSE? If none are false, choose "none of the above."

Select one of the following:

  • they may be motile by either flagella or cilia

  • all eukaryotic cells have cell walls

  • their nuclear membrane has pores in it

  • the nuclear membrane of eukaryotes is contiguous with the endoplasmic reticulum

  • none of the above

Explanation

Question 31 of 107

1

Which of the following statements about microbial growth is FALSE?

Select one of the following:

  • most microorganisms grow very rapidly

  • growth is determined by the size of the individual cells

  • bacteria grow by binary fission

  • unchecked microbial growth can cause food spoilage and disease

  • microorganisms can form very large populations of cells

Explanation

Question 32 of 107

1

Which of the following statements about porins is true?

Select one of the following:

  • they form pores (channels) in the outer membrane of gram-negative bacteria

  • they are found in gram-positive bacteria

  • they allow nutrients to pass through the cytoplasmic membrane of eukaryotes

  • they are membrane-bound organelles found in eukaryotic cells

  • none of the above

Explanation

Question 33 of 107

1

Which of the following statements about lipopolysaccharides is FALSE?

Select one of the following:

  • they are also called endotoxin

  • they cause fever

  • the O-specific polysaccharide is the toxic component

  • they consist of three disscernable regions called lipid A, core polysaccharide, and O-specific polysaccharide

  • they are inactivated by autoclaving

Explanation

Question 34 of 107

1

Which of the following statements about peptidoglycan is FALSE?

Select one of the following:

  • it is present in gram-negative bacteria

  • it is present in gram-positive bacteria

  • it gives bacterial cells their shape and rigidity

  • it completely surrounds bacterial cells

  • it is a large polymer composed solely of amino acids

Explanation

Question 35 of 107

1

Which of the following is NOT a mechanism by which bacteria exchange genetic material?

Select one of the following:

  • conjugation

  • transformation

  • transduction

  • crossing over

Explanation

Question 36 of 107

1

Transcription is _________.

Select one of the following:

  • the process of protein synthesis

  • occurs on ribosomes

  • - the process of protein synthesis
    -occurs on ribosomes

  • none of the above

Explanation

Question 37 of 107

1

Which of the following are eukaryotes?

Select one of the following:

  • Bacteria

  • Archaea

  • Fungi

  • Viruses

  • None of the above

Explanation

Question 38 of 107

1

Which of the following statements about fermentations is FALSE?

Select one of the following:

  • they occur in the absence of oxygen

  • they use an organic molecule as the final electron acceptor

  • they release energy from a sugar or other organic molecule

  • they are considerable less efficient than aerobic respiration

  • they require and electron transport chain

Explanation

Question 39 of 107

1

Which of the following statements about fimbriae is FALSE?

Select one of the following:

  • they are thin, hairlike filaments

  • they can act as adhesins

  • they give bacterial cells motility

  • there may be as many as 100-200 fimbriae per cell

  • they are important virulence factors for some pathogenic bacteria

Explanation

Question 40 of 107

1

Which of the following statements about prokaryotic cells is (are) true?

Select one of the following:

  • they have membrane bound organelles in their cytoplasm

  • their nucleus lacks a membrane and is in direct contact with the cytoplasm

  • their cytoplasm has a microtubule cytoskeleton

  • - they have membrane bound organelles in their cytoplasm
    - their nucleus lacks a membrane and is in direct contact with the cytoplasm

  • - they have membrane bound organelles in their cytoplasm
    - their cytoplasm has a microtubule cytoskeleton

Explanation

Question 41 of 107

1

Which of the following microscopes has the most resolving power and gives the highest magnification?

Select one of the following:

  • brightfield microscope

  • darkfield microscope

  • phase-contrast microscope

  • fluorescence microscope

  • transmission electron microscope

Explanation

Question 42 of 107

1

Which of the following is the correct order of the four steps in the Gram stain?

Select one of the following:

  • 1) safranin 2) iodine 3) alcohol 4) crystal violet

  • 1) iodine 2) safranin 3) alcohol 4) crystal violet

  • 1) crystal violet 2) iodine 3) alcohol 4) safranin

  • 1) crystal violet 2) alcohol 3) iodine 4) safranin

  • 1) alcohol 2) safranin 3) iodine 4) crystal violet

Explanation

Question 43 of 107

1

Which of the following statements about a typical cytoplasmic membrane under normal physiological conditions is NOT true?

Select one of the following:

  • If you believe none of the other 3 choices is a correct answer to the question, choose this choice

  • Membrane proteins float in the lipids of a cytoplasmic membrane under normal conditions

  • The lipids in a cytoplasmic membrane typically have the consistency of a light oil

  • Membrane proteins can freely flip-flop from one layer (leaflet) of a membrane to the other

Explanation

Question 44 of 107

1

The individual microbial species in a mixed sample of microbes can be separated from each other and grown in pure culture by ______.

Select one of the following:

  • plating serial dilution of the sample on agar media

  • the streak plate technique

  • none of the above

  • - plating serial dilution of the sample on agar media
    -the streak plate technique

Explanation

Question 45 of 107

1

The number of cells in an actively growing microbial population doubles with each succeeding generation. A doubling of cell number with each generation is commonly called arithmetic growth.

Select one of the following:

  • The first statement is false; the second statement is false

  • The first statement is true; the second statement is true

  • The first statement is true; the second statement is false

  • The first statement is false; the second statement is true

Explanation

Question 46 of 107

1

Which of the following is NOT a possible reason for the occurrence of a stationary phase in a bacterial growth curve?

Select one of the following:

  • none of the above

  • accumulation of waste products in the growth medium

  • depletion of nutrients in the growth medium

  • the generation time of the dividing organisms

  • a drop in the pH of the growth medium

Explanation

Question 47 of 107

1

The cytoskeleton of prokaryotic cells is _______.

Select one of the following:

  • none of the above

  • composed of microtubules

  • responsible for prokaryotic cytoplasmic streaming

  • an extensive network of filaments that runs throughout the cytoplasm of the cell

Explanation

Question 48 of 107

1

Which of the following microbes produces a slime layer that allows it to colonize devices implanted in skin such as a catheter?

Select one of the following:

  • mycobacteria

  • Bacillus species

  • Streptococci

  • Staphylococci

Explanation

Question 49 of 107

1

The term aciduric means that a microbe _____.

Select one of the following:

  • converts organic acids into CO2 and H2O

  • survives exposure to low pH without being killed

  • grows on amino acids instead of sugars

  • ferments sugars to acids

Explanation

Question 50 of 107

1

Which of the following statements about prokaryotic flagella is true?

Select one of the following:

  • none of the above

  • they are composed of 3 parts: a long filament, a hook, and a basal body

  • their primary function is to mediate the attachment of prokaryotic cells to other cells or surfaces

  • they generate motion by a whip-like or wave motion

Explanation

Question 51 of 107

1

The theory of spontaneous generation was finally disproven once and for all by _________.

Select one of the following:

  • Francesco Redi

  • Paul Ehrlich

  • Robert Kock

  • Louis Pasteur

  • Joseph Lister

Explanation

Question 52 of 107

1

Which of the following statements best explains why a cell would use a Na+ ion-glucose symporter to transport glucose into a cell?

Select one of the following:

  • none of the above

  • the symporter is used to equalize the concentration of glucose inside and outside the cell

  • the symporter is used to transport glucose into a cell that has a higher concentration of glucose inside the cell than outside the cell

  • The symporter is used to transport glucose into a cell that has a lower concentration of glucose inside the cell than there is outside the cell

Explanation

Question 53 of 107

1

The component of the gram-negative outer cell wall membrane makes it a rigid membrane is:

Select one of the following:

  • phosphoglyceride lipids

  • porins

  • the O-specific polysaccharide chain

  • the lipoprotein

  • lipid A

Explanation

Question 54 of 107

1

When glucose is fermented to lactic acid by a microbe, most of the original energy (calories) in the glucose molecule is _____.

Select one of the following:

  • transferred to NADH

  • lost as heat

  • left in the lactic acid molecules

  • converted into ATP

Explanation

Question 55 of 107

1

Viable (standard) plate counts are done by _______.

Select one of the following:

  • none of the above

  • making serial 1/10 dilutions of a bacterial sample and plating a known aliquot of each dilution on an agar growth medium

  • streaking the bacterial sample on a microbial growth medium

  • counting the number of cells in a known dilution of a bacterial sample using a microscope and a Petroff-Hauser counter

Explanation

Question 56 of 107

1

Transmission electron microscopes _______.

Select one of the following:

  • are used to view the three dimensional structure of individual proteins and other macromolecules

  • have a higher magnification than light microscopes

  • none of the above

  • - are used to view the three dimensional structure of individual proteins and other macromolecules
    - have a higher magnification than light microscopes

Explanation

Question 57 of 107

1

Which of the following is the least toxic form of oxygen?

Select one of the following:

  • molecular oxygen

  • singlet oxygen

  • peroxide anion

  • superoxide anion

  • hydroxyl free radical

Explanation

Question 58 of 107

1

The chances of isolating a pathogen that is present in small numbers from a sample that contains a large total number of microbes and many different microbial species can be greatly increased by using a ____.

Select one of the following:

  • defined culture medium

  • complex culture medium

  • selective culture medium

  • reducing culture medium

  • candle jar

Explanation

Question 59 of 107

1

Which of the following statements about preserving food by freezing is true?

Select one of the following:

  • it preserves food by its low temperature and making liquid water unavailable to the microbial cells

  • it kills all of the vegetative microbial cells in food

  • none of the above

  • - it preserves food by its low temperature and making liquid water unavailable to the microbial cells
    - it kills all of the vegetative microbial cells in food

Explanation

Question 60 of 107

1

The basic structure of most cytoplasmic membranes is a lipid bilayer that contains embedded proteins. The embedded proteins in a cytoplasmic membrane are the driving force for formation of the membrane.

Select one of the following:

  • The first statement is false; the second statement is false

  • The first statement is true; the second statement is true

  • The first statement is true; the second statement is false

  • The first statement is false; the second statement is true

Explanation

Question 61 of 107

1

Which of the following stains is commonly used to detect the presence of a capsule around a microbe?

Select one of the following:

  • negative stain

  • endospore stain

  • acid-fast stain

  • gram stain

Explanation

Question 62 of 107

1

The process of sporulation produces 1 endospore from a bacterial cell. Most pathogenic bacteria produce endospores when exposed to harsh conditions.

Select one of the following:

  • The first statement is false; the second statement is false

  • The first statement is true; the second statement is true

  • The first statement is true; the second statement is false

  • The first statement is false; the second statement is true

Explanation

Question 63 of 107

1

Which of the following statements is true of the prokaryotes?

Select one of the following:

  • none of the above

  • their genetic material is surrounded by a double membrane

  • They lack or have a simple cytoskeleton in their cytoplasm

  • They have specialized membrane-bound organelles in their cytoplasm

Explanation

Question 64 of 107

1

The conditions for historical pasteurization are _________.

Select one of the following:

  • 75 C for 15 seconds

  • 100 C for 30 minutes at atmospheric pressure

  • 121 C for 15 minutes at 15 psi of pressure

  • 63 C for 30 minutes

Explanation

Question 65 of 107

1

Which of the following eukaryotic organelles contain a circular molecule of DNA and prokaryotic ribosomes?

Select one of the following:

  • proteosomes

  • the Golgi apparatus

  • the endoplasmic reticulum

  • mitochondria

  • lysosomes

Explanation

Question 66 of 107

1

The endoplasmic reticulum of eukaryotic cells _________.

Select one of the following:

  • none of the above

  • functions as a transport network for newly synthesized proteins

  • is continuous with the nuclear membrane

  • often has ribosomes bound to it

Explanation

Question 67 of 107

1

Which of the following is NOT a function of the cytoskeleton in eukaryotic cells?

Select one of the following:

  • none of the above

  • it enables cytoplasmic streaming and the movement of organelles in cytoplasm

  • it anchors cytoplasmic organelles

  • it carries out the degradation of old and defective proteins in the cytoplasm

Explanation

Question 68 of 107

1

Teichuronic acids are:

Select one of the following:

  • none of the above

  • produced by gram-positive bacteria when they are grown in phosphate-deficient media

  • also called the O-specific antigen

  • a component of lipopolysaccharides

Explanation

Question 69 of 107

1

Streptococci divide ______.

Select one of the following:

  • in three different planes at right angles to each other

  • in two different planes at right angles to each other

  • in a single plane

  • randomly in any plane

Explanation

Question 70 of 107

1

the formation of phosphoenolpyruvate by glycolysis and the transfer of its phosphate group to ADP is an example of _________.

Select one of the following:

  • dephosphorylation

  • substrate level phosphorylation

  • photophosphorylation

  • oxidative phosphorylation

Explanation

Question 71 of 107

1

Reducing media are used to grow ________.

Select one of the following:

  • microaerophilic microbes

  • obligate anaerobes

  • chemoautotrophs

  • capnophilic microbes

Explanation

Question 72 of 107

1

Protozoa historically ___________.

Select one of the following:

  • none of the above

  • are single celled organisms

  • have a prokaryotic cell structure

  • carry out photosynthesis

Explanation

Question 73 of 107

1

The Shaeffer-Fulton endospore stain is useful in the identification of _________.

Select one of the following:

  • Mycobacterium species

  • Clostridium species

  • Bacillus species

  • - Clostridium species
    - Bacillus species

  • - Mycobacterium species
    - Clostridium species
    - Bacillus species

Explanation

Question 74 of 107

1

Peptidoglycan is __________________.

Select one of the following:

  • composed of long polysaccharide chains cross-linked by amino acids

  • found only in gram-positive bacteria

  • none of the above

  • - composed of long polysaccharide chains cross-linked by amino acids
    - found only in gram-positive bacteria

Explanation

Question 75 of 107

1

Motile bacteria have the ability to detect and respond to a concentration gradient of a chemoattractant in their growth environment. Motile bacteria swim in a straight line when they rotate their flagella counterclockwise.

Select one of the following:

  • The first statement is false; the second statement is false

  • The first statement is true; the second statement is true

  • The first statement is true; the second statement is false

  • The first statement is false; the second statement is true

Explanation

Question 76 of 107

1

Passive transport _________.

Select one of the following:

  • none of the above

  • occurs only in prokaryotic cells

  • requires ATP

  • can move a substance across a membrane against a concentration gradient

Explanation

Question 77 of 107

1

A fastidious microbe is a microbe that ________.

Select one of the following:

  • requires elevated levels of CO2 in order to grow

  • does not produce a bad odor when it is grown in culture

  • has special nutrient requirements

  • cannot be grown on artificial media

Explanation

Question 78 of 107

1

Microbes are ecologically important because they _______.

Select one of the following:

  • none of the above

  • are the basis for the food chain in the oceans

  • recycle bound vital elements to a form that can be used again

  • produce most of the oxygen in the atmosphere

Explanation

Question 79 of 107

1

Long, straight, hair-like appendages on the surface of bacterial cells that are not involved in motility are called ______.

Select one of the following:

  • axial filaments

  • microfilaments

  • fimbriae

  • microtubules

  • cilia

Explanation

Question 80 of 107

1

An obligate anaerobe produces adequate or high levels of __________.

Select one of the following:

  • none of the above

  • peroxidase

  • catalase

  • superoxide dismutase

Explanation

Question 81 of 107

1

Indirect methods for measuring microbial growth include all of the following EXCEPT ___________.

Select one of the following:

  • none of the above

  • measuring dry weight

  • measuring turbidity

  • membrane filtration followed by culture of the filter on microbial media

Explanation

Question 82 of 107

1

Bacteria grow by a simple process called binary fission. The generation time for microbial cells is usually 2 or 3 times longer than the generation time for eukaryotic cells.

Select one of the following:

  • The first statement is false; the second statement is false.

  • The first statement is true; the second statement is true.

  • The first statement is true; the second statement is false.

  • The first statement is false; the second statement is true.

Explanation

Question 83 of 107

1

Eukaryotic flagella _______.

Select one of the following:

  • generate motion by rotating like a turbine

  • are long cytoplasmic projections that contain microtubules

  • none of the above

  • - generate motion by rotating like a turbine
    - are long cytoplasmic projections that contain microtubules

Explanation

Question 84 of 107

1

Cells maintain an electrical gradient of -70 mV across their cytoplasmic membrane by selectively maintaining a high concentration of _____ in their cytoplasm and by having protein channels in their cytoplasmic membrane that are freely permeable to _____.

Select one of the following:

  • Na+ ions / Na+ ions

  • K+ ions / Na+ ions

  • K+ ions / K+ ions

  • Na+ ions / K+ ions

Explanation

Question 85 of 107

1

Bacteriostasis means that _______.

Select one of the following:

  • bacterial growth is inhibited, but the bacteria are not killed

  • bacteria are growing (multiplying)

  • all bacteria are killed

  • the number of live microbes have been reduced to a safe level

Explanation

Question 86 of 107

1

Immunofluorescence tests require ___________.

Select one of the following:

  • a phase contrast microscope

  • specific antibodies to a microbe

  • none of the above

  • - specific antibodies to a microbe
    - a phase contrast microscope

Explanation

Question 87 of 107

1

Bacterial cells that are treated with penicillin are killed by _________.

Select one of the following:

  • none of the above

  • hypotonic lysis

  • inhibition of DNA synthesis

  • inhibition of protein synthesis

Explanation

Question 88 of 107

1

All of the following statements are true about all eukaryotic cells EXCEPT one. Which one is the exception?

Select one of the following:

  • none of the above

  • they have a complex cytoskeleton

  • they have membrane-bound organelles in their cytoplasm

  • they have membrane around their nucleus

  • they have a cell wall

Explanation

Question 89 of 107

1

Lipid enveloped viruses are usually more resistant to inactivation (killing) by most antimicrobial agents than naked viruses. The presence of organic matter, grease and/or dirt can interfere with the killing action of an antimicrobial agent.

Select one of the following:

  • The first sentence is true; the second sentence is false

  • The first sentence is false; the second sentence is true

  • The first sentence is false; the second sentence is false

  • The first sentence is true; the second sentence is true

Explanation

Question 90 of 107

1

All of the following are required for a cell to break down glucose by aerobic respiration, EXCEPT for ________.

Select one of the following:

  • peroxisomes

  • oxygen

  • the glycolysis pathway

  • an electron transport chain

Explanation

Question 91 of 107

1

Microorganisms in biofilms:

Select one of the following:

  • develop as porous, mushroom-like structures when there are lots of nutrients present in the biofilm

  • typically have the same sensitivity to antibiotics as they do when growing freely in broth culture

  • none of the above

  • - develop as porous, mushroom-like structures when there are lots of nutrients present in the biofilm
    - typically have the same sensitivity to antibiotics as they do when growing freely in broth culture

Explanation

Question 92 of 107

1

Transposons _________.

Select one of the following:

  • can cause frameshift mutations

  • are small pieces of DNA that can move from one location in a DNA molecule to another location

  • on the same or a different chromosome

  • - can cause frameshift mutations
    - are small pieces of DNA that can move from one location in a DNA molecule to another location

  • none of the above

Explanation

Question 93 of 107

1

Transduction is the transfer of genes from one bacterium to another by ________.

Select one of the following:

  • naked DNA in solution

  • viruses

  • direct contact between the cells

  • cell fusion

Explanation

Question 94 of 107

1

The scanning electron microscope is primarily used to visualize the _______.

Select one of the following:

  • structure of atoms

  • internal structures of cells

  • structure of large molecules such as proteins

  • surface of cells and objects

Explanation

Question 95 of 107

1

The region of logarithmic growth in a bacterial growth curve _________.

Select one of the following:

  • can be used to determine the generation time of a microbe

  • is a region where the number of new cells being formed is equal to the number of cells that are dying

  • - is a region where the number of new cells being formed is equal to the number of cells that are dying
    - can be used to determine the generation time of a microbe

  • none of the above

Explanation

Question 96 of 107

1

Non-membranous organelles in eukaryotic cells include all of the following EXCEPT:

Select one of the following:

  • ribosomes

  • peroxisomes

  • centrioles

  • proteosomes

Explanation

Question 97 of 107

1

The purpose of iodine in the Gram stain is to __________.

Select one of the following:

  • stain the cells purple

  • stain cells a light red color

  • enhance staining of gram-positive bacteria with crystal violet

  • enhance the staining of gram-negative bacteria with safranin

Explanation

Question 98 of 107

1

The theory of biogenesis was proven by ________.

Select one of the following:

  • Alexander Fleming

  • Robert Koch

  • Louis Pasteur

  • John Needham

Explanation

Question 99 of 107

1

The genetic material of prokaryotic cells is __________.

Select one of the following:

  • attached to the cell's cytoskeleton

  • usually a single circular molecule of DNA

  • enclosed in a porous membrane

  • none of the above

Explanation

Question 100 of 107

1

A chemoautotroph uses ______ as a carbon source and ______ as an energy source.

Select one of the following:

  • CO2 / light

  • CO2 / chemical compounds

  • organic compounds / light

  • organic compounds / chemical compounds

Explanation

Question 101 of 107

1

The structural polymer that protects bacterial cells from osmotic lysis is the _______.

Select one of the following:

  • cytoplasmic membrane

  • glycocalyx

  • peptidoglycan

  • capsule

Explanation

Question 102 of 107

1

The first person to prove that microbes can cause infectious disease in humans was _______.

Select one of the following:

  • Antoni van Leeuwenhock

  • Robert Koch

  • Louis Pasteur

  • Francesco Redi

Explanation

Question 103 of 107

1

Snapping division in prokaryotic cells produces _______.

Select one of the following:

  • packets of 8 cocci

  • chains of rods

  • spirochetes

  • V and Y shapes

Explanation

Question 104 of 107

1

Osmotic pressure is defined as the hydrostatic pressure required to ______.

Select one of the following:

  • stop the net flow of water across a semi-permeable membrane

  • prevent a cell from bursting

  • cause a cell to burst

  • none of the above

Explanation

Question 105 of 107

1

Nucleosomes are _________.

Select one of the following:

  • present in both prokaryotic and eukaryotic cells

  • complexes of DNA and histones

  • extra-chromosomal pieces of DNA

  • - present in both prokaryotic and eukaryotic cells
    - complexes of DNA and histones

Explanation

Question 106 of 107

1

Microbes are beneficial because they _______.

Select one of the following:

  • recycle vital elements from dead organisms and organic wastes

  • produces oxygen

  • - recycle vital elements from dead organisms and organic wastes
    - produces oxygen

  • none of the above

Explanation

Question 107 of 107

1

The conversion of nitrogen gas (N2) into ammonia _______.

Select one of the following:

  • requires siderophores

  • is carried out by all plants

  • occurs during photosynthesis in plants

  • none of the above

Explanation

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