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Microbial Exam 1 Oldies Questions Compilation

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Microbial Exam 1 Oldies Questions Compilation
Ilsa West
Test por Ilsa West, actualizado hace más de 1 año
Ilsa West
Creado por Ilsa West hace más de 9 años
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Pregunta 1

Pregunta
A substance found in the plasma membrane of eukaryotic cells but not the plasma membrane of most prokaryotic cells is ______.
Respuesta
  • cholesterol
  • phospholipids
  • proteins
  • phospholipids and proteins
  • cholesterol, phospholipids, and proteins

Pregunta 2

Pregunta
An acidophile is an organism that ____.
Respuesta
  • 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

Pregunta 3

Pregunta
Bacteria that use O2 for aerobic respiration when it is present, but also grow in its absence by fermenting substrates are called ____.
Respuesta
  • obligate aerobes
  • facultative anaerobes
  • microaerophile
  • aerotolerant anaerobes
  • obligate anaerobes

Pregunta 4

Pregunta
Bacteria that lack cell walls readily lyse in _____ solution.
Respuesta
  • hypotonic
  • hypertonic
  • isotonic
  • hypertonic and hypotonic
  • none of the above

Pregunta 5

Pregunta
Bacteria in the logarithmic phase of growth ______.
Respuesta
  • 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

Pregunta 6

Pregunta
Capsules are important virulence factors for bacteria because they ____.
Respuesta
  • 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

Pregunta 7

Pregunta
Chains of cocci are called _______.
Respuesta
  • streptococci
  • diplococci
  • staphylococci
  • sarcinae
  • coccobacilli

Pregunta 8

Pregunta
Ignatz Semmelweis discovered that the incidence of peurperal (childbirth) fever could be lowered dramatically by ______.
Respuesta
  • penicillin
  • hand and instrument washing in chlorinated lime
  • prayer
  • having doctors deliver babies instead of midwives
  • none of the above

Pregunta 9

Pregunta
In glycolysis, one molecule of glucose is converted into _____.
Respuesta
  • CO2 and H2O
  • citrate
  • ethanol and CO2
  • glycogen
  • two molecules of pyruvate

Pregunta 10

Pregunta
Media that are specifically designed to grow anaerobic bacteria are called ____ media.
Respuesta
  • reducing
  • differential
  • selective
  • chemically defined
  • enrichment

Pregunta 11

Pregunta
Microorganisms that grow only at temperatures between -10 and 20 C are called _____.
Respuesta
  • thermophiles
  • mesophiles
  • psychrophiles
  • psychrotrophs
  • extreme thermophiles

Pregunta 12

Pregunta
Negative stains _______.
Respuesta
  • 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

Pregunta 13

Pregunta
Siderophores are _______.
Respuesta
  • 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

Pregunta 14

Pregunta
The cell wall component that protects bacteria against lysis by osmotic pressure is _________.
Respuesta
  • peptidoglycan
  • teichoic acid
  • lipopolysaccharide
  • phospholipid
  • porins

Pregunta 15

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

Pregunta 16

Pregunta
The outer membrane of gram-negative bacteria contains ________.
Respuesta
  • peptidoglycan
  • lipopolysaccharide
  • porins
  • - lipopolysaccharide - porins
  • - peptidoglycan - lipopolysaccharide - porins

Pregunta 17

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

Pregunta 18

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

Pregunta 19

Pregunta
The degree of relatedness between two microorganisms can best be determined by ________.
Respuesta
  • biochemical tests
  • morphological features
  • DNA hybridization
  • differential staining
  • DNA base composition

Pregunta 20

Pregunta
The enzyme that converts H2O2 into H2O and O2 is called _____.
Respuesta
  • lysozyme
  • superoxide dismutase
  • catalase
  • peroxidase
  • oxygenase

Pregunta 21

Pregunta
The newly published Bergey's Manual of Systemic Bacteriology, 2nd Edition classifies prokaryotes into taxonomic units primarily based upon _____.
Respuesta
  • morphological criteria
  • biochemical tests
  • rRNA nucleotide sequence
  • - morphological criteria - biochemical tests

Pregunta 22

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

Pregunta 23

Pregunta
The transfer of DNA from one bacterium to another by a bacteriophage is called ________.
Respuesta
  • conjugation
  • transformation
  • transportation
  • transduction
  • lysogeny

Pregunta 24

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

Pregunta 25

Pregunta
The process of destroying all microbial life forms is called ______.
Respuesta
  • sterilization
  • antisepsis
  • disinfection
  • sanitization
  • bacteriostasis

Pregunta 26

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

Pregunta 27

Pregunta
Which of the following statements about endospores is FALSE?
Respuesta
  • 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

Pregunta 28

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

Pregunta 29

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

Pregunta 30

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

Pregunta 31

Pregunta
Which of the following statements about microbial growth is FALSE?
Respuesta
  • 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

Pregunta 32

Pregunta
Which of the following statements about porins is true?
Respuesta
  • 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

Pregunta 33

Pregunta
Which of the following statements about lipopolysaccharides is FALSE?
Respuesta
  • 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

Pregunta 34

Pregunta
Which of the following statements about peptidoglycan is FALSE?
Respuesta
  • 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

Pregunta 35

Pregunta
Which of the following is NOT a mechanism by which bacteria exchange genetic material?
Respuesta
  • conjugation
  • transformation
  • transduction
  • crossing over

Pregunta 36

Pregunta
Transcription is _________.
Respuesta
  • the process of protein synthesis
  • occurs on ribosomes
  • - the process of protein synthesis -occurs on ribosomes
  • none of the above

Pregunta 37

Pregunta
Which of the following are eukaryotes?
Respuesta
  • Bacteria
  • Archaea
  • Fungi
  • Viruses
  • None of the above

Pregunta 38

Pregunta
Which of the following statements about fermentations is FALSE?
Respuesta
  • 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

Pregunta 39

Pregunta
Which of the following statements about fimbriae is FALSE?
Respuesta
  • 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

Pregunta 40

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

Pregunta 41

Pregunta
Which of the following microscopes has the most resolving power and gives the highest magnification?
Respuesta
  • brightfield microscope
  • darkfield microscope
  • phase-contrast microscope
  • fluorescence microscope
  • transmission electron microscope

Pregunta 42

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

Pregunta 43

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

Pregunta 44

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

Pregunta 45

Pregunta
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.
Respuesta
  • 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

Pregunta 46

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

Pregunta 47

Pregunta
The cytoskeleton of prokaryotic cells is _______.
Respuesta
  • 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

Pregunta 48

Pregunta
Which of the following microbes produces a slime layer that allows it to colonize devices implanted in skin such as a catheter?
Respuesta
  • mycobacteria
  • Bacillus species
  • Streptococci
  • Staphylococci

Pregunta 49

Pregunta
The term aciduric means that a microbe _____.
Respuesta
  • 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

Pregunta 50

Pregunta
Which of the following statements about prokaryotic flagella is true?
Respuesta
  • 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

Pregunta 51

Pregunta
The theory of spontaneous generation was finally disproven once and for all by _________.
Respuesta
  • Francesco Redi
  • Paul Ehrlich
  • Robert Kock
  • Louis Pasteur
  • Joseph Lister

Pregunta 52

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

Pregunta 53

Pregunta
The component of the gram-negative outer cell wall membrane makes it a rigid membrane is:
Respuesta
  • phosphoglyceride lipids
  • porins
  • the O-specific polysaccharide chain
  • the lipoprotein
  • lipid A

Pregunta 54

Pregunta
When glucose is fermented to lactic acid by a microbe, most of the original energy (calories) in the glucose molecule is _____.
Respuesta
  • transferred to NADH
  • lost as heat
  • left in the lactic acid molecules
  • converted into ATP

Pregunta 55

Pregunta
Viable (standard) plate counts are done by _______.
Respuesta
  • 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

Pregunta 56

Pregunta
Transmission electron microscopes _______.
Respuesta
  • 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

Pregunta 57

Pregunta
Which of the following is the least toxic form of oxygen?
Respuesta
  • molecular oxygen
  • singlet oxygen
  • peroxide anion
  • superoxide anion
  • hydroxyl free radical

Pregunta 58

Pregunta
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 ____.
Respuesta
  • defined culture medium
  • complex culture medium
  • selective culture medium
  • reducing culture medium
  • candle jar

Pregunta 59

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

Pregunta 60

Pregunta
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.
Respuesta
  • 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

Pregunta 61

Pregunta
Which of the following stains is commonly used to detect the presence of a capsule around a microbe?
Respuesta
  • negative stain
  • endospore stain
  • acid-fast stain
  • gram stain

Pregunta 62

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

Pregunta 63

Pregunta
Which of the following statements is true of the prokaryotes?
Respuesta
  • 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

Pregunta 64

Pregunta
The conditions for historical pasteurization are _________.
Respuesta
  • 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

Pregunta 65

Pregunta
Which of the following eukaryotic organelles contain a circular molecule of DNA and prokaryotic ribosomes?
Respuesta
  • proteosomes
  • the Golgi apparatus
  • the endoplasmic reticulum
  • mitochondria
  • lysosomes

Pregunta 66

Pregunta
The endoplasmic reticulum of eukaryotic cells _________.
Respuesta
  • 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

Pregunta 67

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

Pregunta 68

Pregunta
Teichuronic acids are:
Respuesta
  • 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

Pregunta 69

Pregunta
Streptococci divide ______.
Respuesta
  • 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

Pregunta 70

Pregunta
the formation of phosphoenolpyruvate by glycolysis and the transfer of its phosphate group to ADP is an example of _________.
Respuesta
  • dephosphorylation
  • substrate level phosphorylation
  • photophosphorylation
  • oxidative phosphorylation

Pregunta 71

Pregunta
Reducing media are used to grow ________.
Respuesta
  • microaerophilic microbes
  • obligate anaerobes
  • chemoautotrophs
  • capnophilic microbes

Pregunta 72

Pregunta
Protozoa historically ___________.
Respuesta
  • none of the above
  • are single celled organisms
  • have a prokaryotic cell structure
  • carry out photosynthesis

Pregunta 73

Pregunta
The Shaeffer-Fulton endospore stain is useful in the identification of _________.
Respuesta
  • Mycobacterium species
  • Clostridium species
  • Bacillus species
  • - Clostridium species - Bacillus species
  • - Mycobacterium species - Clostridium species - Bacillus species

Pregunta 74

Pregunta
Peptidoglycan is __________________.
Respuesta
  • 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

Pregunta 75

Pregunta
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.
Respuesta
  • 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

Pregunta 76

Pregunta
Passive transport _________.
Respuesta
  • none of the above
  • occurs only in prokaryotic cells
  • requires ATP
  • can move a substance across a membrane against a concentration gradient

Pregunta 77

Pregunta
A fastidious microbe is a microbe that ________.
Respuesta
  • 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

Pregunta 78

Pregunta
Microbes are ecologically important because they _______.
Respuesta
  • 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

Pregunta 79

Pregunta
Long, straight, hair-like appendages on the surface of bacterial cells that are not involved in motility are called ______.
Respuesta
  • axial filaments
  • microfilaments
  • fimbriae
  • microtubules
  • cilia

Pregunta 80

Pregunta
An obligate anaerobe produces adequate or high levels of __________.
Respuesta
  • none of the above
  • peroxidase
  • catalase
  • superoxide dismutase

Pregunta 81

Pregunta
Indirect methods for measuring microbial growth include all of the following EXCEPT ___________.
Respuesta
  • none of the above
  • measuring dry weight
  • measuring turbidity
  • membrane filtration followed by culture of the filter on microbial media

Pregunta 82

Pregunta
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.
Respuesta
  • 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.

Pregunta 83

Pregunta
Eukaryotic flagella _______.
Respuesta
  • 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

Pregunta 84

Pregunta
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 _____.
Respuesta
  • Na+ ions / Na+ ions
  • K+ ions / Na+ ions
  • K+ ions / K+ ions
  • Na+ ions / K+ ions

Pregunta 85

Pregunta
Bacteriostasis means that _______.
Respuesta
  • 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

Pregunta 86

Pregunta
Immunofluorescence tests require ___________.
Respuesta
  • a phase contrast microscope
  • specific antibodies to a microbe
  • none of the above
  • - specific antibodies to a microbe - a phase contrast microscope

Pregunta 87

Pregunta
Bacterial cells that are treated with penicillin are killed by _________.
Respuesta
  • none of the above
  • hypotonic lysis
  • inhibition of DNA synthesis
  • inhibition of protein synthesis

Pregunta 88

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

Pregunta 89

Pregunta
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.
Respuesta
  • 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

Pregunta 90

Pregunta
All of the following are required for a cell to break down glucose by aerobic respiration, EXCEPT for ________.
Respuesta
  • peroxisomes
  • oxygen
  • the glycolysis pathway
  • an electron transport chain

Pregunta 91

Pregunta
Microorganisms in biofilms:
Respuesta
  • 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

Pregunta 92

Pregunta
Transposons _________.
Respuesta
  • 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

Pregunta 93

Pregunta
Transduction is the transfer of genes from one bacterium to another by ________.
Respuesta
  • naked DNA in solution
  • viruses
  • direct contact between the cells
  • cell fusion

Pregunta 94

Pregunta
The scanning electron microscope is primarily used to visualize the _______.
Respuesta
  • structure of atoms
  • internal structures of cells
  • structure of large molecules such as proteins
  • surface of cells and objects

Pregunta 95

Pregunta
The region of logarithmic growth in a bacterial growth curve _________.
Respuesta
  • 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

Pregunta 96

Pregunta
Non-membranous organelles in eukaryotic cells include all of the following EXCEPT:
Respuesta
  • ribosomes
  • peroxisomes
  • centrioles
  • proteosomes

Pregunta 97

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

Pregunta 98

Pregunta
The theory of biogenesis was proven by ________.
Respuesta
  • Alexander Fleming
  • Robert Koch
  • Louis Pasteur
  • John Needham

Pregunta 99

Pregunta
The genetic material of prokaryotic cells is __________.
Respuesta
  • attached to the cell's cytoskeleton
  • usually a single circular molecule of DNA
  • enclosed in a porous membrane
  • none of the above

Pregunta 100

Pregunta
A chemoautotroph uses ______ as a carbon source and ______ as an energy source.
Respuesta
  • CO2 / light
  • CO2 / chemical compounds
  • organic compounds / light
  • organic compounds / chemical compounds

Pregunta 101

Pregunta
The structural polymer that protects bacterial cells from osmotic lysis is the _______.
Respuesta
  • cytoplasmic membrane
  • glycocalyx
  • peptidoglycan
  • capsule

Pregunta 102

Pregunta
The first person to prove that microbes can cause infectious disease in humans was _______.
Respuesta
  • Antoni van Leeuwenhock
  • Robert Koch
  • Louis Pasteur
  • Francesco Redi

Pregunta 103

Pregunta
Snapping division in prokaryotic cells produces _______.
Respuesta
  • packets of 8 cocci
  • chains of rods
  • spirochetes
  • V and Y shapes

Pregunta 104

Pregunta
Osmotic pressure is defined as the hydrostatic pressure required to ______.
Respuesta
  • 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

Pregunta 105

Pregunta
Nucleosomes are _________.
Respuesta
  • 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

Pregunta 106

Pregunta
Microbes are beneficial because they _______.
Respuesta
  • 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

Pregunta 107

Pregunta
The conversion of nitrogen gas (N2) into ammonia _______.
Respuesta
  • requires siderophores
  • is carried out by all plants
  • occurs during photosynthesis in plants
  • none of the above
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