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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

Pregunta 1 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • cholesterol

  • phospholipids

  • proteins

  • phospholipids and proteins

  • cholesterol, phospholipids, and proteins

Explicación

Pregunta 2 de 107

1

An acidophile is an organism that ____.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 3 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • obligate aerobes

  • facultative anaerobes

  • microaerophile

  • aerotolerant anaerobes

  • obligate anaerobes

Explicación

Pregunta 4 de 107

1

Bacteria that lack cell walls readily lyse in _____ solution.

Selecciona una de las siguientes respuestas posibles:

  • hypotonic

  • hypertonic

  • isotonic

  • hypertonic and hypotonic

  • none of the above

Explicación

Pregunta 5 de 107

1

Bacteria in the logarithmic phase of growth ______.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 6 de 107

1

Capsules are important virulence factors for bacteria because they ____.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 7 de 107

1

Chains of cocci are called _______.

Selecciona una de las siguientes respuestas posibles:

  • streptococci

  • diplococci

  • staphylococci

  • sarcinae

  • coccobacilli

Explicación

Pregunta 8 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • penicillin

  • hand and instrument washing in chlorinated lime

  • prayer

  • having doctors deliver babies instead of midwives

  • none of the above

Explicación

Pregunta 9 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • CO2 and H2O

  • citrate

  • ethanol and CO2

  • glycogen

  • two molecules of pyruvate

Explicación

Pregunta 10 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • reducing

  • differential

  • selective

  • chemically defined

  • enrichment

Explicación

Pregunta 11 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • thermophiles

  • mesophiles

  • psychrophiles

  • psychrotrophs

  • extreme thermophiles

Explicación

Pregunta 12 de 107

1

Negative stains _______.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 13 de 107

1

Siderophores are _______.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 14 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • peptidoglycan

  • teichoic acid

  • lipopolysaccharide

  • phospholipid

  • porins

Explicación

Pregunta 15 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 16 de 107

1

The outer membrane of gram-negative bacteria contains ________.

Selecciona una de las siguientes respuestas posibles:

  • peptidoglycan

  • lipopolysaccharide

  • porins

  • - lipopolysaccharide
    - porins

  • - peptidoglycan
    - lipopolysaccharide
    - porins

Explicación

Pregunta 17 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 18 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 19 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • biochemical tests

  • morphological features

  • DNA hybridization

  • differential staining

  • DNA base composition

Explicación

Pregunta 20 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • lysozyme

  • superoxide dismutase

  • catalase

  • peroxidase

  • oxygenase

Explicación

Pregunta 21 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • morphological criteria

  • biochemical tests

  • rRNA nucleotide sequence

  • - morphological criteria
    - biochemical tests

Explicación

Pregunta 22 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 23 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • conjugation

  • transformation

  • transportation

  • transduction

  • lysogeny

Explicación

Pregunta 24 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 25 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • sterilization

  • antisepsis

  • disinfection

  • sanitization

  • bacteriostasis

Explicación

Pregunta 26 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 27 de 107

1

Which of the following statements about endospores is FALSE?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 28 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 29 de 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?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 30 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 31 de 107

1

Which of the following statements about microbial growth is FALSE?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 32 de 107

1

Which of the following statements about porins is true?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 33 de 107

1

Which of the following statements about lipopolysaccharides is FALSE?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 34 de 107

1

Which of the following statements about peptidoglycan is FALSE?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 35 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • conjugation

  • transformation

  • transduction

  • crossing over

Explicación

Pregunta 36 de 107

1

Transcription is _________.

Selecciona una de las siguientes respuestas posibles:

  • the process of protein synthesis

  • occurs on ribosomes

  • - the process of protein synthesis
    -occurs on ribosomes

  • none of the above

Explicación

Pregunta 37 de 107

1

Which of the following are eukaryotes?

Selecciona una de las siguientes respuestas posibles:

  • Bacteria

  • Archaea

  • Fungi

  • Viruses

  • None of the above

Explicación

Pregunta 38 de 107

1

Which of the following statements about fermentations is FALSE?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 39 de 107

1

Which of the following statements about fimbriae is FALSE?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 40 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 41 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • brightfield microscope

  • darkfield microscope

  • phase-contrast microscope

  • fluorescence microscope

  • transmission electron microscope

Explicación

Pregunta 42 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 43 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 44 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 45 de 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.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 46 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 47 de 107

1

The cytoskeleton of prokaryotic cells is _______.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 48 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • mycobacteria

  • Bacillus species

  • Streptococci

  • Staphylococci

Explicación

Pregunta 49 de 107

1

The term aciduric means that a microbe _____.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 50 de 107

1

Which of the following statements about prokaryotic flagella is true?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 51 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • Francesco Redi

  • Paul Ehrlich

  • Robert Kock

  • Louis Pasteur

  • Joseph Lister

Explicación

Pregunta 52 de 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?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 53 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • phosphoglyceride lipids

  • porins

  • the O-specific polysaccharide chain

  • the lipoprotein

  • lipid A

Explicación

Pregunta 54 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • transferred to NADH

  • lost as heat

  • left in the lactic acid molecules

  • converted into ATP

Explicación

Pregunta 55 de 107

1

Viable (standard) plate counts are done by _______.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 56 de 107

1

Transmission electron microscopes _______.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 57 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • molecular oxygen

  • singlet oxygen

  • peroxide anion

  • superoxide anion

  • hydroxyl free radical

Explicación

Pregunta 58 de 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 ____.

Selecciona una de las siguientes respuestas posibles:

  • defined culture medium

  • complex culture medium

  • selective culture medium

  • reducing culture medium

  • candle jar

Explicación

Pregunta 59 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 60 de 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.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 61 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • negative stain

  • endospore stain

  • acid-fast stain

  • gram stain

Explicación

Pregunta 62 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 63 de 107

1

Which of the following statements is true of the prokaryotes?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 64 de 107

1

The conditions for historical pasteurization are _________.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 65 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • proteosomes

  • the Golgi apparatus

  • the endoplasmic reticulum

  • mitochondria

  • lysosomes

Explicación

Pregunta 66 de 107

1

The endoplasmic reticulum of eukaryotic cells _________.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 67 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 68 de 107

1

Teichuronic acids are:

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 69 de 107

1

Streptococci divide ______.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 70 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • dephosphorylation

  • substrate level phosphorylation

  • photophosphorylation

  • oxidative phosphorylation

Explicación

Pregunta 71 de 107

1

Reducing media are used to grow ________.

Selecciona una de las siguientes respuestas posibles:

  • microaerophilic microbes

  • obligate anaerobes

  • chemoautotrophs

  • capnophilic microbes

Explicación

Pregunta 72 de 107

1

Protozoa historically ___________.

Selecciona una de las siguientes respuestas posibles:

  • none of the above

  • are single celled organisms

  • have a prokaryotic cell structure

  • carry out photosynthesis

Explicación

Pregunta 73 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • Mycobacterium species

  • Clostridium species

  • Bacillus species

  • - Clostridium species
    - Bacillus species

  • - Mycobacterium species
    - Clostridium species
    - Bacillus species

Explicación

Pregunta 74 de 107

1

Peptidoglycan is __________________.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 75 de 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.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 76 de 107

1

Passive transport _________.

Selecciona una de las siguientes respuestas posibles:

  • none of the above

  • occurs only in prokaryotic cells

  • requires ATP

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

Explicación

Pregunta 77 de 107

1

A fastidious microbe is a microbe that ________.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 78 de 107

1

Microbes are ecologically important because they _______.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 79 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • axial filaments

  • microfilaments

  • fimbriae

  • microtubules

  • cilia

Explicación

Pregunta 80 de 107

1

An obligate anaerobe produces adequate or high levels of __________.

Selecciona una de las siguientes respuestas posibles:

  • none of the above

  • peroxidase

  • catalase

  • superoxide dismutase

Explicación

Pregunta 81 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • none of the above

  • measuring dry weight

  • measuring turbidity

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

Explicación

Pregunta 82 de 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.

Selecciona una de las siguientes respuestas posibles:

  • 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.

Explicación

Pregunta 83 de 107

1

Eukaryotic flagella _______.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 84 de 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 _____.

Selecciona una de las siguientes respuestas posibles:

  • Na+ ions / Na+ ions

  • K+ ions / Na+ ions

  • K+ ions / K+ ions

  • Na+ ions / K+ ions

Explicación

Pregunta 85 de 107

1

Bacteriostasis means that _______.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 86 de 107

1

Immunofluorescence tests require ___________.

Selecciona una de las siguientes respuestas posibles:

  • a phase contrast microscope

  • specific antibodies to a microbe

  • none of the above

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

Explicación

Pregunta 87 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • none of the above

  • hypotonic lysis

  • inhibition of DNA synthesis

  • inhibition of protein synthesis

Explicación

Pregunta 88 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 89 de 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.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 90 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • peroxisomes

  • oxygen

  • the glycolysis pathway

  • an electron transport chain

Explicación

Pregunta 91 de 107

1

Microorganisms in biofilms:

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 92 de 107

1

Transposons _________.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 93 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • naked DNA in solution

  • viruses

  • direct contact between the cells

  • cell fusion

Explicación

Pregunta 94 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • structure of atoms

  • internal structures of cells

  • structure of large molecules such as proteins

  • surface of cells and objects

Explicación

Pregunta 95 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 96 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • ribosomes

  • peroxisomes

  • centrioles

  • proteosomes

Explicación

Pregunta 97 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 98 de 107

1

The theory of biogenesis was proven by ________.

Selecciona una de las siguientes respuestas posibles:

  • Alexander Fleming

  • Robert Koch

  • Louis Pasteur

  • John Needham

Explicación

Pregunta 99 de 107

1

The genetic material of prokaryotic cells is __________.

Selecciona una de las siguientes respuestas posibles:

  • attached to the cell's cytoskeleton

  • usually a single circular molecule of DNA

  • enclosed in a porous membrane

  • none of the above

Explicación

Pregunta 100 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • CO2 / light

  • CO2 / chemical compounds

  • organic compounds / light

  • organic compounds / chemical compounds

Explicación

Pregunta 101 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • cytoplasmic membrane

  • glycocalyx

  • peptidoglycan

  • capsule

Explicación

Pregunta 102 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • Antoni van Leeuwenhock

  • Robert Koch

  • Louis Pasteur

  • Francesco Redi

Explicación

Pregunta 103 de 107

1

Snapping division in prokaryotic cells produces _______.

Selecciona una de las siguientes respuestas posibles:

  • packets of 8 cocci

  • chains of rods

  • spirochetes

  • V and Y shapes

Explicación

Pregunta 104 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 105 de 107

1

Nucleosomes are _________.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 106 de 107

1

Microbes are beneficial because they _______.

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 107 de 107

1

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

Selecciona una de las siguientes respuestas posibles:

  • requires siderophores

  • is carried out by all plants

  • occurs during photosynthesis in plants

  • none of the above

Explicación

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