Microbiology Quiz

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251 Questions

What is a key structural difference between Methanogens and Eukaryotes?

Presence of non-peptidoglycan cell wall in Methanogens

What differentiates Prokaryotes from Eukaryotes in terms of DNA?

Eukaryotes have DNA in circular form

Which organism is characterized by an absorptive heterotroph mode of nutrition and a cell wall made up of chitin?

Penicillium chrysogenum

What sets apart Protozoans from other single-celled eukaryotes?

They have animal-like digestion

How do Algae differ from other photosynthetic autotrophs?

They vary in pigmentation and cell wall composition

What characteristic distinguishes Animals as ingestive heterotrophs?

Mode of nutrition involving ingesting food

Which of the following is NOT a Parasitic Protozoan causing diseases in humans?


'Red Tide' is commonly associated with which type of organism?


What was Pasteur's final contribution mentioned in the text?

Heating grape juice to kill bacteria without ruining its taste

Based on Pasteur's 1857 hypothesis, what did he propose about microorganisms?

They are responsible for disease

What was Robert Koch's contribution to microbiology as mentioned in the text?

Creating the first photomicrograph of bacteria

What are Koch's postulates used for in microbiology?

To determine if a suspected agent causes disease

What is the purpose of pasteurization, as described in the text?

To kill bacteria in grape juice without affecting its quality

What is the significance of yeasts in grape juice fermentation?

They ferment grape juice into alcohol

What did Pasteur's hypothesis suggest about bacteria in grape juice?

They reproduce and produce acids

What was Koch's role in studying infectious diseases?

He identified the specific causative agents for diseases

What is the main focus of Koch's postulates mentioned in the text?

Establishing criteria to determine if a microorganism causes a specific disease

What was the main purpose of John Needham's experiment in 1750?

To support the theory of spontaneous generation

In the Swan-Necked Flask Experiment by Pasteur, why did he observe that the infusion remained sterile indefinitely?

Since he sealed the flask preventing the entry of microbes

What conclusion did Pasteur draw from his Swan-Necked Flask Experiment regarding the origin of microbes in the liquid?

They were from dust particles in the air settling in the bend

Which aspect led to Francisco Redi questioning spontaneous generation in 1668?

The observation of covered flasks with gauze

What was the outcome of Pasteur's experiment on fermentation of grape juice into wine?

Yeasts were responsible for fermenting grape juice into alcohol

How did Pasteur's modern-day version of fermentation experiment differ from his earlier experiments?

It investigated factors causing spoilage rather than fermentation

Why did Redi use both sealed and unsealed flasks in his experiment?

To demonstrate that life does not come from non-living matter

What critical factor did Needham propose as a cause for inanimate matter coming to life?

'Life force' present in all living organisms

Who successfully correlated cholera propagation with poor water sanitation?

John Snow

Which individual introduced antiseptic techniques into nursing practices during the Crimean War?

Florence Nightingale

Who observed that women giving birth in medical institutions had a much higher mortality rate from puerperal fever compared to home births?

Ignaz Semmelweis

What did Joseph Lister introduce into surgical theatres in the 1850s for disinfection purposes?

Phenol spray

Variolation was a common practice in the 1720s for preventing which disease?


Who led to the emergence of the branches of microbiology known as infection control and epidemiology?

John Snow

Which method involved handwashing with chlorinated lime water to decrease mortality rates in medical settings?

Handwashing method

What is the approximate resolving power of the high power objective lens with light of 450 nm (blue light)?

0.35 μm

Which type of lens has a working distance of approximately 0.1 mm?

Oil immersion lens

What is the value of 1 nanometer in meters?

$10^{-9}$ meter

Which property increases as we move from low power to oil immersion objective lenses?

Numerical aperture

What was the refractive index of oil mentioned in the text?


Which components are responsible for controlling light intensity in a brightfield microscope according to the text?

Aperture diaphragm control and substage condenser

What is the formula for resolution as mentioned in the text?

$\frac{0.5}{\lambda} d = n\sin\theta$

What is the function of the exciter filter in fluorescence microscopy?

Absorbs short-wavelength radiation

Which common fluorochrome is often attached to DNA probes or antibodies that bind specific cellular components?

Fluorescein isothiocyanate (FITC)

What does the dichromatic mirror do in fluorescence microscopy?

Reflects short wavelengths

In fluorescence microscopy, what type of light does the mercury arc lamp emit?

Short wavelengths

Which fluorochrome is commonly used for staining DNA in microscopy?


What is the main characteristic of green fluorescent protein mentioned in the text?

Attaches to antibodies

Why is it mentioned in the text that most things observed are 3D, not flat, in microscopy?

To highlight the importance of DIC microscopy

What is the primary advantage of dark-field microscopy?

Allows observation of live unstained specimens

In phase-contrast microscopy, how do deviated and undeviated rays interact to produce contrast?

They cancel each other out

What is the role of Abbe condenser in microscopy?

Enhances resolution by focusing light onto the specimen

Which feature distinguishes dark-field microscopy from other optical microscopy techniques?

Use of a specialized dark-field stop

What is the significance of differential interference contrast (DIC) microscopy in microbiology?

Provides 3D visualization of live biological samples

How do phase plates contribute to the functionality of phase-contrast microscopes?

Enhance contrast by manipulating light phases

What is the main advantage of phase contrast microscopy over bright-field microscopy?

Ability to observe live unstained specimens

Which type of microscope has a higher practical magnification, light or transmission electron?

Transmission Electron Microscope

What is the main source of contrast in a Transmission Electron Microscope?

Scattering of electrons

How is the focusing mechanism different between a Light Microscope and a Transmission Electron Microscope?

Adjust lens position mechanically

What is the resolution limit of a human eye in terms of micrometers?

$0.2$ $ ext{μm}$

What is commonly used as the specimen mount in a Light Microscope?

Glass slide

In which type of microscope is the medium of travel air?

Light Microscope

What distinguishes the type of lens used in a Transmission Electron Microscope from that used in a Light Microscope?

Glass lens vs. Electromagnet

What factor determines the best resolution between a Light Microscope and a Transmission Electron Microscope?

Type of lens

What is the method of changing magnification in a Transmission Electron Microscope?

Adjust current to the magnetic lens

What is the role of the bacterial cell wall in resisting osmotic forces?

Maintaining cell shape

Which structure is a component of peptidoglycan in the bacterial cell wall?

N-acetylmuramic acid (NAM)

What is the function of Lipid A in the gram-negative bacterial cell wall?

Embedded in the outer membrane

What distinguishes gram-negative cell walls from gram-positive cell walls?

Outer membrane structure

Who developed the staining technique that differentiates between gram-negative and gram-positive bacteria?

Hans Christian Gram

What is the outcome when a bacterial cell is stained with crystal violet under the Gram staining technique?

'All cells remain purple.'

Which part of the Gram staining process acts as a mordant to keep cells purple?

'Slide being flooded with iodine'

What is the result of binary fission in bacteria?

Formation of two daughter cells

Under a microscope, which bacteria appear as spiraled rods?


What is the morphology of coccobacilli under a microscope?

Intermediate between cocci and bacilli

Which bacterial structure is responsible for the replication process in binary fission?


What is the typical shape of spirilla under a microscope?


Which type of bacteria resembles both cocci and bacilli under a microscope?


What is the primary mode of reproduction for bacteria discussed in the text?

Binary fission

Which bacterium appears as slightly elongated cocci under a microscope?


In bacterial reproduction through budding, what is the role of the young bud?

To move the original bacterial chromosome into the daughter cell

Which external structure of a bacterial cell is responsible for chemotaxis and phototaxis?


What is the function of Pili in bacterial cells?


Regarding flagellated bacteria, what does 'Peritrichous' refer to?

Multiple flagella located all over the cell surface

What is the primary structural component of the bacterial cell wall?

Peptidoglycan layer

What role do fimbriae play in bacterial cells?

Adhesion to surfaces

Which common method of bacterial reproduction involves the formation of spores?

Spores of Actinomycetes

In bacterial arrangement, what does 'COCCI' refer to?

'Berry'-shaped bacteria

What is the purpose of the decolourizing agent in the Gram stain technique?

To break down the thick cell wall of Gram-negative cells

What is the role of the counterstain in the Gram stain technique?

To differentiate between Gram-positive and Gram-negative cells

Why does the Gram stain fail to identify Mycobacterium and Nocardia bacteria?

Due to their waxy cell walls that reject crystal violet

What is deposited between the membranes during the formation of an endospore?

Cortex of calcium and dipicolinic acid

Which bacterial genera are known to produce endospores?

Bacillus and Clostridium

What is the main content of bacterial cytosol according to the text?

Proteins (enzymes)

What type of bacteria are characterized by being acid-fast in staining techniques?

Bacteria with waxy cell walls

Which component provides contrast to the primary stain in acid-fast staining techniques?


What is the function of polyhydroxybutyrate (PHB) inclusion bodies in some bacteria?

Energy storage

What role does the spore coat play in the formation of endospores in bacteria?

Protection against dehydration and chemicals

Which type of microorganism would likely thrive in an environment with a NaCl concentration of 10^-7M?

Staphylococcus aureus

In which pH range would Acidophiles be most likely to thrive?


What is the NaCl concentration of human blood, making it suitable for which type of microorganism?


Which microorganism listed is most likely to thrive in an Alkaline pH environment?

Ferroplasma spp.

At what NaCl concentration would Extreme Halophiles typically thrive?


Which microorganism is most likely to be found thriving in an environment with a pH of 2?

Lemon juice

In which type of environment would Bacillus alcalophilus thrive based on the given data?

$10^{-14}$ M NaCl

Which type of bacteria requires oxygen levels of 2% to 10% for growth?


What type of bacteria does not use aerobic metabolism but tolerates oxygen?

Aerotolerant anaerobes

Which enzyme content is found in obligate anaerobes according to the text?

  • SOD - Catalase

What is the basis of all solid media used for culturing microorganisms?


In which type of media is the exact chemical composition known but is difficult to prepare?

Synthetic media

Which microbial communities have synergistic relationships among numerous microorganisms attached to surfaces?


What is the sample you are trying to grow called in microbiology?


What differentiates defined (synthetic) media from complex media used in microbiology?

'Exact chemical composition known' versus 'difficult to prepare'

Which method is used to obtain a true aseptic collection of urine?


What is the key characteristic of a pure culture?

Genetically identical

In which method are cells retained by a membrane filter while measuring population size?

Membrane Transfer

Which technique dilutes the inoculum across the surface of an agar plate to isolate organisms into a pure culture?

Streak Plate

What is the purpose of streaking in successive areas of the plate during the Streak Plate technique?

To deposit only one bacterial cell every few millimeters

Which method is suitable for measuring population size in large populations?

Serial Dilutions

What is the key feature of a population that makes turbidity measurement appropriate for estimating its size?

'Large Population' characteristic

'The key - all cells in pure culture are genetically identical.' Why is this statement crucial in microbiology?

'Pure Cultures' simplify genetic studies


Selective media favor the growth of specific microorganisms, while differential media help differentiate among different bacteria.

What is the purpose of adding Eosin, Methylene Blue, and Bile Salts to SELECTIVE MEDIA?

To kill gram-positive bacteria while being harmless to gram-negative bacteria.

What is the significance of pH 7.3 for bacterial colonies?

It is ideal for differentiating among different types of bacteria.

Why are Bile Salts added to some selective media?

To selectively kill gram-negative bacteria.

How do DIFFERENTIAL MEDIA aid in distinguishing between bacterial colonies?

Through changes in the appearance of colonies or the medium itself.

Gamma-hemolysis refers to:

No hemolysis occurring on blood agar.

Carbohydrate utilization tubes containing different carbohydrates and pH indicators are examples of:

Differential Media

NaCl is increased in some media to encourage the growth of:


What was the main contribution of Fransisco Redi to the theory of abiogenesis?

Demonstrating the presence of a 'life force' causing inanimate matter to come to life.

What was John Needham's reasoning behind supporting spontaneous generation?

Heated vials sufficiently to kill everything.

What was the outcome of Pasteur's swan-necked flask experiment regarding the microbes in the liquid?

Infusion remained sterile indefinitely.

In Pasteur's experiment with grape juice fermentation, what led him to conclude that microbes in the liquid came from the air?

Observation that infusion remains sterile indefinitely.

What causes the fermentation of grape juice according to Pasteur's experiment?

Yeasts fermenting grape juice into alcohol.

What was the purpose of sealing the flask on Day 2 in Pasteur's grape juice fermentation experiment?

To inoculate the juice with bacteria.

Based on the text, what was the main conclusion drawn by Pasteur regarding the origin of microbes in liquids?

'Life force' is not required for life as microbes originate from dust particles in the air.

What was the key observation leading Pasteur to conclude that sterilized grape juice remained sterile indefinitely?

'Life force' present in inanimate matter.

What contribution is attributed to Robert Koch based on the text?

First photomicrograph of bacteria

What did Pasteur contribute to microbiology according to the text?

Developing pasteurization

Which statement correctly reflects Pasteur's 1857 hypothesis?

Germ theory of disease states microorganisms are responsible for diseases

What did Pasteurization aim to achieve based on the text?

Heat grape juice to destroy microbes while preserving its quality

What is the purpose of Koch's Postulates as mentioned in the text?

To identify and isolate disease-causing agents

In what process does Pasteurization use heat according to the text?

To kill most bacteria without affecting juice quality

What distinguishes Pasteur's modern-day fermentation experiment from his earlier versions mentioned in the text?

'Bacteria ferment grape juice into acids' hypothesis modification

How did Robert Koch contribute to microbiology based on the text?

'Simple staining techniques' development

Who introduced antiseptic techniques into nursing practices during the Crimean War?

Florence Nightingale

Which individual successfully correlated cholera propagation with poor water sanitation?

John Snow

What was the common practice in the 1720s related to smallpox prevention?


Which individual hypothesized that cadaver particles in medical students were causing deaths from puerperal fever?

Ignaz Semmelweis

What was Joseph Lister known for introducing in the 1850s to surgical theatres?

Antiseptic technique

Which individual conducted detailed statistical studies connecting poor hospital conditions to soldier deaths?

Florence Nightingale

What was the outcome of Variolation as a smallpox prevention method in the 1720s?

~2% mortality rate for Variolated patients

What major branches of microbiology emerged due to John Snow's work on cholera?

Infection control and Epidemiology

What distinguishes Archaea from Bacteria based on the text?

Type of cell wall

Which group of microorganisms is NOT included in the 7 key groups mentioned in the text?


Why are some species of Bacteria harmful to humans according to the text?

Peptidoglycan cell wall composition

What is a common mode of reproduction for Protozoa as discussed in the text?

Asexual reproduction

What is a key characteristic of small multicellular animals among microorganisms?


What is the primary component of Viroids as described in the text?

RNA enclosed in a protein shell

What differentiates Viruses from other microorganisms mentioned in the text?

Protein and nucleic acid composition

What is the formula for calculating resolution as mentioned in the text?

0.5 λ / NA

Which type of objective lens has the highest approximate resolving power with light of 450 nm (blue light) according to the text?

Oil Immersion

Based on the text, what is the approximate focal length of a High Power objective lens?

1.8-2.0 mm

What is the purpose of the substage condenser in a brightfield microscope according to the text?

Enhance resolution

What factor determines the working distance of an objective lens as stated in the text?

Slide thickness

Which unit of measurement is used to represent a nanometer according to the provided table?


What does the Abbé Equation relate to as discussed in the text?

Resolving power of a lens

What is the primary purpose of the Abbe condenser in dark-field microscopy?

To enhance contrast by blocking direct light from reaching the objective lens.

In phase contrast microscopy, what part of the bacterium causes a deviation in light?

Phase plate

What effect does a phase plate have on deviated and undeviated rays in phase contrast microscopy?

They cancel each other out to create contrast.

What is the significance of DIC (Differential Interference Contrast) microscopy in microbiology?

It provides 3D-like images without staining.

Which characteristic distinguishes dark-field microscopy from phase contrast microscopy?

Illumination of the sample from the sides

What role does the dark-field stop play in dark-field microscopy?

To restrict direct light from entering the objective lens.

What does a dampened wave crest signify in phase contrast microscopy?

Cancellation of deviated and undeviated rays

What is the function of the dichromatic mirror in fluorescence microscopy?

Reflects long wavelengths and transmits short wavelengths

Which fluorochrome is often attached to DNA probes or antibodies that bind specific cellular components in fluorescence microscopy?

Fluorescein isothiocyanate (FITC)

What is the primary difference between DIC microscopy and fluorescence microscopy?

DIC microscopy enhances contrast through interference, while fluorescence microscopy labels specific cellular components.

Why are exciter and barrier filters essential in fluorescence microscopy?

To ensure only desired wavelengths reach the specimen

What is the main purpose of fluorochrome-stained specimens in fluorescence microscopy?

To label specific cellular components for visualization

Which statement best describes the role of the condenser lens in light microscopy?

Focuses light onto the specimen to improve resolution

In fluorescence microscopy, what is the function of the mercury arc lamp?

To generate short-wavelength light for excitation

What is the key difference in the focusing mechanism between Light Microscopes and Transmission Electron Microscopes?

Adjust lens position mechanically vs. adjust current to the magnetic lens

Which type of microscope has a higher practical magnification, Light Microscope or Transmission Electron Microscope?

Transmission Electron Microscope

What is the primary source of radiation in a Light Microscope?

Visible light

Which type of lens is used in a Transmission Electron Microscope for focusing the electron beam?

Objective lens

What is the medium of travel for electrons in a Transmission Electron Microscope?

High vacuum

How do Light Microscopes and Transmission Electron Microscopes differ in terms of resolution?

$0.2 \mu m$ vs. $0.2 \text{ nm}$

'Z stacks' are a result of which technique mentioned in the text?

Confocal Scanning Laser Microscopy (CSLM)

'Differential light absorption' is associated with which type of microscope according to the text?

Light Microscope

'Metal grid' is commonly used as a specimen mount in which type of microscope?

"Transmission Electron Microscope"

What is the term for bacteria that can change shape but do not have a defined form?


During binary fission in bacteria, what happens after chromosome replication finishes?

Daughter cells separate

Which type of bacteria appear as spiral-shaped under a microscope?


What is the term for bacteria that are rod-shaped under a microscope?


In binary fission, what occurs after replication begins in bacteria?

Chromosome replication starts

Which type of bacteria are spherical in shape under a microscope?


What is the term for bacteria that are short rods under a microscope?


What is the primary function of Pili in bacterial cells?


In bacterial reproduction by budding, what is the role of the young bud?

To house the daughter DNA molecule

Which external structure of a bacterial cell is responsible for forming a tuft of polar flagella?

Peritrichous flagellum

What is the process by which flagellated bacteria exhibit a biased random walk through chemotaxis?

Run and tumble

What is the function of fimbriae in bacterial cells?

Attachment to surfaces

What does the arrangement of bacteria in cocci signify?

A spherical structure

Which structure is associated with glycolcalyx in bacterial cells?


What is the function of the origin of replication in E.coli cells?

Replication of DNA

What is the primary function of the bacterial cell wall?


Which component is NOT typically found in the structure of peptidoglycan in bacterial cell walls?


What distinguishes Gram-negative cell walls from Gram-positive cell walls?

Presence of a periplasmic space

What is the purpose of the Gram stain in microbiology?

To distinguish between Gram-negative and Gram-positive bacteria

In the Gram stain process, what is the function of the iodine solution?

Act as a mordant

What is a key component of Gram-negative cell walls that contributes to pathogenicity?

Lipid A

Which scientist developed the Gram stain, a widely used staining technique in microbiology?

Hans Christian Gram

What structural feature of Gram-negative cell walls aids in attachment to other bacteria or cells?

'O side chain' of lipopolysaccharide

What happens to Gram-negative cells during the Gram staining process described in the text?

They become colorless

What is the function of the decolourizing agent in the Gram staining process?

To wash away the stain from Gram-positive cells

What is the result of the Ziehl-Neelsen acid-fast staining technique on acid-fast bacteria?

They appear red/pink

What is deposited between the membranes of an endospore during its maturation process?


Which bacterial components are described as liquid contents that include ions, carbs, proteins, lipids, and waste products?


Which bacterial structures have very waxy cell walls that reject crystal violet in the Gram stain?

Bacillus and Clostridium

What is the role of the counterstain in the Gram staining process?

To provide contrast to primary stain

What bacterial components are known for being resistant to heat and chemicals due to an unknown process?


Which bacterial structures align DNA along the cell's long axis?


What is the primary purpose of determining the generation time in microbial growth studies?

To predict the exponential growth rate of the population

In the context of microbiology, what does the long-term stationary phase typically indicate?

Sustainable equilibrium with minimal cell division occurring

What does the term 'lag phase' in microbial growth refer to?

A period of slow growth due to nutrient depletion

Which factor is crucial in determining the exponential growth of a microbial population?

The generation time of the microbial species

What role does 'log10 number of viable cells' play in understanding microbial growth?

It helps track the number of living cells over time

In which range of NaCl concentration (M) would you expect to find a moderate halophile?


How does the death phase affect the availability of nutrients for remaining microbial cells?

Nutrient availability increases due to dying cells releasing nutrients

Which pH range would be most suitable for the growth of Acidophiles?


What does the term 'exponential phase' signify in the context of microbial growth?

A rapid increase in cell numbers through binary fission

Which of the following environments would be conducive to the growth of Sulfolobus acidocaldarius?

Lemon juice (pH 3)

How does the concept of 'Mathematics of Growth' aid in understanding microbial populations?

It provides insights into population doubling and generation time

Where would you likely find Microcystis aeruginosa based on the pH conditions mentioned?

Soap (pH 9)

At what approximate pH would you expect to find Nitrosomonas species based on the provided data?


Which bacterium is likely to be found in seawater according to the text?

Nitrosomonas spp.

'Physarum polycephalum' is likely to thrive in which environment based on the given pH conditions?

Baking soda (pH 8.5)

'Cyandidium caldarium' and 'Thiobacillus thiooxidans' are both likely to be found in which type of environment?

'Acid mine drainage'

What is the purpose of using a Durham tube in anaerobic culture?

To trap gas produced during acid fermentation

Which optical property relates to the transparency of microorganisms?


What type of agar is MacConkey agar and what does it do?

Selective and differential; enhances the growth of certain species and distinguishes them based on appearance

What clinical sampling method involves fine needle aspiration from a vein?

Fine Needle Aspiration from Vein

Which shape is NOT used in identifying microorganisms based on their solid culture appearance?


What does the methylene blue serve as in anaerobic cultures?

Anaerobic indicator

What is the primary function of Palladium pellets in an anaerobic chamber?

Catalyze reactions to remove O2 gas

What is the significance of using MacConkey agar for bacterial culture?

Selective and differential, enhancing specific species growth and differentiation based on appearance.

At what temperature range does Bɑcillus psychrophilus exhibit its minimum growth rate?

-10 to 0°C

What is the optimum temperature range for Chlɑmydomonɑs nivɑlis?

4 to 6°C

Which microorganism shows a temperature range of 25-32°C for its optimum growth rate?

Trichomonɑs vɑginɑlis

What is the maximum temperature range for Pyrolobus fumɑrii's growth?


What type of microorganism is Amoebɑ proteus based on its growth temperature ranges?


Which bacteria would most likely be characterized as a mesophile based on its optimum growth rate?

Neisseriɑ gonorrhoeɑe

What distinguishes Psychrophiles from Psychrotolerants based on their temperature preferences?

-10 and 10°C difference in minimum growth rate

What is the maximum growth temperature range for Pseudomonɑs fluorescens based on the given data?

40 to 50°C

Test your knowledge of fermentation and pasteurization with this quiz covering Pasteur's final contribution. Evaluate hypothesis related to yeast inoculation, bacteria reproduction, acid production, and alcohol fermentation in grape juice.

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