MicroBiology MCQs Chapter 2

During the decline phase, many cells exhibit unusual shapes which is caused by ______.

A. involution
B. ingestion
C. digestion
D. high energy conversion

ANSWER: A


A method used to measure bacterial growth that requires the use of a series of dilution tubes is ________.

A. spectrophotometric B. staining
C. serial dilution
D. cell mass
ANSWER: C


An indication of bacterial growth due to ________

A. acidity nature
B. alkalinity
C. turbidity
D. cell dry biomass

ANSWER: C


Organisms that can tolerate very low pH conditions are called ________.

A. acidophiles
B. thermophiles
C. hyperthermophiles
D. alkalinophiles

ANSWER: A


Organisms that prefer temperatures above 50°C are known as ________.

A. thermophiles
B. acidophiles
C. hyperthermophiles
D. alkalinophile

ANSWER: A


Which organism can tolerate one environmental condition but still live in another

A. aerobes
B. anaerobes
C. facultative
D. endospores producing microbes ANSWER: C


An enzyme which can break into H2O and O2 is ________.

A. catalase
B. oxidase
C. urease
D. proteases

ANSWER: A


Obligate anaerobes are killed by a highly reactive form of oxygen called ________.

A. superoxide
B. reactive oxygen
C. free radicals
D. dismutase

ANSWER: A


When cells lose water and their membranes shrink away from the cell wall indicates that they are undergoing ________.

A. lysis
B. plasmolysis

C. lysogenic

D. caryolysis
ANSWER: D


Organisms that have many special nutritional needs are ________

A. fastidious
B. Lactobacillus sp
C. Mycobacterium sp
D. all the above

ANSWER: D


The processes of endospore formation is known as ________.

A. sporulation.
B. germination
C. propagation
D. binary fission

ANSWER: A


The two bacterial genera that produce endospores are ________.

A. Bacillus, Clostridium
B. Escherichia coli, Bacillus
C. Actinobacter, Bacillus
D. Staphylococcus, Streptococcus ANSWER: A


A method of pure culturing bacteria by means of an agar plates and an inoculating loop is _____.

A. streak plate
B. pour plate
C. spread plate
D. quadrant streak
ANSWER: A


A culture medium which contains known specific kinds and amounts of chemicals is a _______.

A. Liquid
B. solid
C. selective
D. defined synthetic

ANSWER: D


A medium that encourages the growth of some organisms but suppresses others is a ______.

A. liquid
B. solid
C. defined synthetic

D. selective
ANSWER: D


Isolated organisms can be maintained in a pure culture called ________

A. stock cultures
B. standard culture

C. enrichment culture
D. selective culture

ANSWER: A


A preserved culture maintained to keep its characteristics as originally defined is a _______

A. reference culture
B. standard culture
C. enrichment culture
D. selective culture

ANSWER: A


Pasteur is credited with all the following except ________.

A. construction of swan necked vessels
B. development of a vaccine for rabies
C. development of the technique for rabies
D. became the director of the Pasteur institute in Paris, France

ANSWER: D


One of the most important contributions of Robert Koch in his development of the germ theory of disease was the ________.

A. use of test animals in research
B. use of the microscope
C. development of the technique of pure culturing

D. development of the busen burner
ANSWER: C


Fungi can be characterized as ________.

A. photosynthetic organism
B. organisms lacking a cell wall
C. organisms lacking a true nucleus
D. organism that absorb nutrients from their environment

ANSWER: D


Phycology is the study of ________.

A. molds
B. bacteria

C. viruses

D. algae
ANSWER: D


The total magnification of a microscope with the low power lens (10X) and ocular lens (15X) in position would be _______.

A. 25

B. 15

C. 150

D. 1500
ANSWER: C


A major difference between the SEM and the TEM is that the SEM ________.

A. can resolve objects smaller than 20 nanometer
B. requires less of a vacuum system than the TEM
C. can create three dimensional images
D. does not require the use of any metal coating of the specimen ANSWER: C


Heat fixation accomplishes all the following expect ________.

A. helps the dye to penetrate the cells

B. kills the bacteria on the slide
C. decreases distortion of the cells prior to the addition of strains

D. fixes the organisms to the slide
ANSWER: C


The condenser lens of a microscope ________.

A. increases the magnification
B. generally can magnify an object ten times
C. increases the light refraction
D. converges light beams onto the specimen

ANSWER: D


If a bacterium measures 0.3 micrometer, it would measure how many angstroms

A. 300
B. 30

C. 3000

D. 3
ANSWER: C


An example of a non­ionizing type of radiation which is microbiocidal is _______.

A. Gamma rays
B. UV rays
C. X­rays
D. electrons

ANSWER: C


Which of the following would not be consistent with eukaryotic organisms

A. membrane bound organelle
B. presence of histones
C. cell membranes lacking sterols
D. paired chromosomes

ANSWER: B


The peptidoglycan layer of the cell wall ________.

A. consist of lipopolysaccharide
B. is formed from repeating molecules of glunac and murnac

C. represents the lipid bilayer
D. lacks teichoic acids
ANSWER: B


Dipicolinic acid is commonly associated with ________.

A. endospore coats
B. lipopolysaccharide of gram negative bacteria
C. peptidoglycan layer of gram positive bacteria
D. mesosomes

ANSWER: A


Bacterial flagella ________.

A. attach to the cell wall via the teichoic acids and calcium

B. form a hook after leaving the cell
C. are about the same size as eukaryotic flagella

D. are composed of lipopolysaccharides units called flagellin

ANSWER: B


Select the most CORRECT statement in relation to serial dilution.

A. diluted samples are transferred to nutrient broth tubes
B. the number of colonies on the plate is multiplied by the denominator of the dilution factor

C. the test can accurately measure live and dead cells
D. countable plates should contain between 10 and 30 colonies
ANSWER: B


Which of the following methods is NOT used to determine bacterial numbers.

A. turbidity
B. serial dilution
C. direct microscopic counts
D. all the above

ANSWER: D


Temperature can control bacteria because ________.

A. freezing will kill all the bacteria
B. hot temperatures (above 80�c) will denature bacterial protein

C. refrigerator temperatures stop the growth of all bacteria
D. no bacteria can live above 180�F
ANSWER: B


Endospores ________.

A. are generally formed for protection and reproduction
B. are formed only when conditions become unfavorable.
C. contain dipicolinic acid and calcium
D. contain laminated layers of peptidoglycan called the exosporium
ANSWER: C


Select the most INCORRECT statement concerning culturing of bacteria ________.

A. a synthetic medium consists of unidentifiable ingredients such as those found in beef extract

B.
C. the streak plate method uses agar plates and a wire inoculating loop
D. an enrichment medium contains ingredients such as blood which can enhance the growth of
certain organisms

ANSWER: A


A specially calibrated counting chamber used with direct microscopic counts is called _____.

A. petroff hausser counter
B. haemocytometer counter
C. Geiger­Muller counter

ANSWER: A


Trace elements such as copper and zinc often serve as ________.

A. cofactors
B. inducers
C. receptors
D. inhibitors

ANSWER: A


A substance that forms an insoluble complex with stain and serves to fix the color to bacterial

cell is called _______.

A. mordant
B. intensifier
C. fixative
D. dyes

ANSWER: A


The ratio of diameter of lenses to its focal length is referred as ________.

A. magnification
B. resolution
C. numerical aperture
D. focal length

ANSWER: A


The ability to reveal closely adjacent points as separate and distinct _______.

A. magnification
B. resolution
C. numerical aperture
D. focal length

ANSWER: B


In _______ microscope, the field surrounding a specimen appears black, while the object itself is brightly illuminated

A. compound
B. phase contrast

C. dark field
D. fluorescence
ANSWER: C


Use of single stain to color the bacteria is commonly called as ________ staining.

A. simple
B. Gram
C. differential
D. negative

ANSWER: A


A substance that forms an insoluble complex with stain and serves to fix the color to bacterial cell is called as ________.

A. mordant

B. intensifier

C. fixative

D. dyes
ANSWER: A


In Grams Staining, Grams iodine is act as ________.

A. counter stain
B. primary stain
C. secondary stain
D. mordant

ANSWER: D


A stain which on ionization gives positively charged molecules is referred as ________.

A. acidic stain
B. Basic stain

C. anionic stain
D. basic mordant

ANSWER: A


The charged group of bacterial cell surface produces attraction between basic stain ______.

A. negative
B. positive
C. neutral
D. all of the above

ANSWER: B


The differential staining technique refers as ________ staining.

A. monochrome
B. Gram
C. negative
D. endospore

ANSWER: B


In Gram Staining, Safranin is act as ________.

A. primary stain
B. mordant
C. counter stain
D. decolorizer

ANSWER: C


In Gram staining, differentiation of microorganisms is based on ________.

A. cell wall
B. plasma membrane
C. capsule
D. flagella

ANSWER: A


 

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