Microbiology Lab Techniques: Fermentation

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Questions and Answers

What is the purpose of the Durham tubes?

To detect the presence of oxygen in the fermentation process

To sterilize the fermentation broth

To measure the pH of the fermentation broth

To collect and measure the gas produced during fermentation (correct)

What is the main difference between homolactic and heterolactic fermentation?

The temperature of the fermentation process

The type of sugar used in the fermentation process

The presence or absence of oxygen

The type of product formed during fermentation (correct)

What is the characteristic of fungi that allows them to exist in two different forms?

Eukaryotic cell structure

Morphogenesis

Dimorphism (correct)

Polymorphism

What is the function of hyphae in fungi?

To absorb nutrients from the environment Signup and view all the answers

What kingdom do fungi belong to?

Fungi Signup and view all the answers

What is the importance of handwashing in the lab?

To prevent the spread of infection Signup and view all the answers

What are fomites in the context of microbiology?

Inanimate objects that carry microorganisms Signup and view all the answers

What is the purpose of heat fixation in the smear preparation?

To fix the cells to the slide Signup and view all the answers

What is the difference between basic and acidic stains?

Basic stains are positively charged, acidic stains are negatively charged Signup and view all the answers

What is the purpose of flaming the openings of test tubes?

To sterilize the opening of the tube Signup and view all the answers

What is a pure culture?

A culture containing a single type of microorganism Signup and view all the answers

What is the purpose of aseptic technique?

To prevent contamination of cultures Signup and view all the answers

How is the negative stain done?

By using a stain with a negative charge Signup and view all the answers

What is observed in a good quality smear?

A clear, even distribution of cells Signup and view all the answers

What are the standard conditions of incubation for bacterial cultures?

37°C and 5% CO2 Signup and view all the answers

What type of stain is used to observe endospores?

Endospore Stain Signup and view all the answers

Which of the following fungi is known to cause disease and has a growth form that contrasts with the other fungi observed?

Candida Signup and view all the answers

What is the function of steam in the Acid Fast Stain and Endospore Stain?

To decolorize the specimen Signup and view all the answers

Which of the following is an example of a catabolic reaction?

Fermentation Signup and view all the answers

What is the primary function of phenol red in fermentation tests?

To indicate a pH below 6.8 Signup and view all the answers

Which of the following protozoa is known to cause disease?

All of the above Signup and view all the answers

What is the primary function of hyphae in fungi?

To absorb nutrients Signup and view all the answers

What is the primary function of mycelium in fungi?

To absorb nutrients Signup and view all the answers

What is the primary function of fermentation?

To generate energy Signup and view all the answers

What type of organisms are the Protozoa?

Eukaryotes Signup and view all the answers

Study Notes

Microbiology Laboratory Techniques

Durham tubes are used to detect gas production during fermentation.

Indicator Dyes

Phenol red is a pH indicator used to detect acid production during fermentation, which changes the color of the medium from red to yellow.

Carbohydrate Fermentation

The following sugars were tested: glucose, lactose, sucrose, and fructose.

Types of Fermentation

Homolactic fermentation is a type of fermentation that produces lactic acid as the only product.
Heterolactic fermentation is a type of fermentation that produces lactic acid and other products, such as ethanol and carbon dioxide.

Non-Fermenters

In broths set with non-fermenters, there will be no gas production, acid production, or color change.

Fungi Characteristics

Fungi belong to the kingdom Fungi.
They are eukaryotes, meaning their cells have a true nucleus.
Fungi are heterotrophic, meaning they cannot photosynthesize.

Fungal Morphology

Dimorphic, as it applies to fungi, means that they can exist in two different forms, such as yeast and mold.
Hyphae are long, branching filaments that make up the mycelium.
Mycelium is the vegetative part of the fungus, consisting of a mass of hyphae.

Fungal Reproduction

Fungi can reproduce by producing spores, which are similar to the seeds of plants.

Week 1: Laboratory Safety and Microbiology

Know lab syllabus and safety contract
Location of safety equipment
Handwashing experiment (Ex 25): C/C transient and resident microbes
Incubation conditions: standard condition of incubation for bacterial cultures
Fomites: Ex 4 Microbes are Everywhere
Alpha, beta, and gamma hemolysis
Modes of transmission: at least 4 modes
Review questions: 1,2,4,5 / 1,2 / 2,3,4

Week 2: Microscope and Aseptic Technique

Microscope parts and usage
Proper microscope usage
Microscope put away checklist
Shapes and arrangements of bacteria
Aseptic technique
Flaming sterilization of loop
Broth, slant, and deep: purpose of flaming test tube openings
Pure culture definition
Review questions: 1,3,4,5,6 / 2,3 / 1,2,3,4

Week 3: Smear, Gram Stain, and Negative Stain

Good quality smear characteristics
Basic and acidic stains: definition and examples
Heat fixation purpose
Unstained cells characteristics
Gram stain procedure
Stains used in Gram stain
Interpretation of Gram stain results
Negative stain procedure
Stain used in negative stain
Charge of negative stain
Usage of negative stain
Observation of negative stain
Review questions: 1,2,5 / 1,2,3,4 / 1,2

Week 4: Acid Fast Stain and Endospore Stain

Acid fast stain procedure
Stains used in acid fast stain
Steam usage in acid fast stain
Interpretation of acid fast stain results
Endospore stain procedure
Stains used in endospore stain
Steam usage in endospore stain
Interpretation of endospore stain results
Review questions: 1,2,3,4 / 1,2,3,4 / 2,4

Week 5: Fungi and Protozoa

Fungi kingdom: characteristics (eukaryotic, non-photosynthetic)
Dimorphic fungi: definition and examples
Hyphae and mycelium: definition and function
Fungi reproduction methods
Rhizopus, Penicillium, Aspergillus, Candida slides: recognition and characteristics
Diseases caused by each fungus
Protozoa kingdom: characteristics (eukaryotic)
Multicellular form possibility
7 Protozoa slides: recognition and characteristics (Trypanozoma cruzi, Trypanosoma brucei, Trichomonas, Leishmania, Giardia, Balantidium, Plasmodium, Toxoplasma)
Diseases caused by each Protozoa
Review questions: 1,4 / 2,5 / 2 / 1

Week 5: Fermentation Tests

Fermentation products
Media used in fermentation tests
Phenol red: pH indicator (below 6.8)
Fermentation definition
Catabolic reactions: definition and function
Durham tubes purpose
Phenol red purpose
Sugars tested in fermentation
Homolactic and heterolactic fermentation: definitions and examples

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Description

This quiz covers laboratory techniques used in microbiology, including fermentation tests, indicator dyes, and carbohydrate fermentation. Topics include Durham tubes, phenol red, and types of fermentation.