Cab H2 MB

What are the environments where microbes can be found?

Water, air, earth, and on human bodies.

What is a microbiome?

A community of microbes that inhabit a particular environment.

Where do environmental microbiomes exist?

On surfaces such as lab benches.

How do human microbes vary?

They differ from one area to another and among individuals.

What is a ubiquitous microorganism?

A microorganism that is harmless.

What is the lab purpose regarding microbes?

To attempt to culture (grow) some microbes from the environment.

What is required for culturing bacteria?

Macronutrients, energy source, and any necessary growth factors.

What is a chemically defined medium?

Medium whose exact chemical composition is known.

What is complex media?

Media whose exact chemical composition varies slightly from batch to batch.

What do chemoheterotrophic bacteria typically require for growth?

Protein in the form of meat extracts and peptones.

What is nutrient broth?

A used liquid complex medium.

What is nutrient agar?

Nutrient broth plus agar added to become a solid medium.

What is agar derived from?

Marine red algae.

At what temperature does agar liquefy?

100°C.

What is the purpose of steam sterilization/autoclaving?

To sterilize culture media that are heat stable.

At what temperature and pressure does autoclaving typically occur?

121°C at 15 pounds of pressure (psi) for 15 minutes.

What do Petri plates provide for microbial examination?

A large surface area for examination of colonies.

What happens to liquid media after suitable incubation?

They become turbid/cloudy due to bacterial growth.

What is a colony?

A population of cells that arises from a single bacterial cell.

What is a colony-forming unit?

A colony that may arise from a group of the same microbes attached to one another.

What happens when many species of bacteria give rise to colonies?

Each colony appearing different usually represents a different species.

How do you prepare 100 ml of nutrient broth?

Add correct amount of nutrient broth powder to 100 ml of distilled water in a flask and dissolve it.

What temperature should the nutrient broth be autoclaved at?

121°C.

What effect does agar have on culture medium?

It solidifies the medium.

What should you do to the Petri dishes while pouring melted agar?

Keep the flask at an angle and work quickly to avoid contamination.

Why is it necessary to heat the mouth of the flask during agar pouring?

To maintain sterility and prevent contamination.

How should inoculated plates be incubated?

Inverted to prevent condensation on the agar surface.

What is a facultative anaerobe?

An organism that can grow with or without oxygen.

What is the typical temperature of the human body?

Approximately 37°C.

What are fungi?

Eukaryotic unicellular or multicellular organisms.

How do fungi obtain nutrients?

By absorbing dissolved organic materials through their cell walls and plasma membranes.

How do yeasts reproduce?

Asexually through uneven cell division or budding.

What are molds?

Multicellular filamentous fungi.

What is a thallus?

A macroscopic mold colony.

What are the structures that make up a mold colony?

Mycelium and hyphae.

What distinguishes septate hyphae from coenocytic hyphae?

Septate hyphae have individual cells separated by septa, whereas coenocytic hyphae are a continuous mass of cytoplasm.

What are asexual spores produced by molds called?

Conidiospores.

What is a saprophyte?

An organism that obtains nutrients from dead organic matter.

What are the main divisions of fungi based on rRNA similarities?

Zygomycota, Ascomycota, and Basidiomycota.

What kind of medium is used to culture fungi?

Sabouraud agar.

What conditions do fungi prefer compared to bacteria?

Fungi grow better in acidic conditions and can tolerate higher osmotic pressure.

What are the sexual spores of Ascomycota called?

Ascospores.

What are the spores produced by Basidiomycota called?

Basidiospores.

What is an example of a saprophytic mold?

Penicillium or Aspergillus.

What is the role of mycelium in fungi?

It serves as the vegetative part of the fungus, absorbing nutrients.

What happens to the nutrient broth labeled ‘Not Sterile’ after incubation?

It may become cloudy or show microbial growth.

What effect does the pH have on Sabouraud agar?

It inhibits the growth of many other organisms.

What is the purpose of swirling agar in Petri dishes?

To cover empty spaces and ensure even coverage.

What does the term 'TNTC' stand for in counting colonies?

Too Numerous To Count.

What must happen to media before being used for culturing?

They must be sterilized.

What distinguishes between aerobic and anaerobic fungi?

Aerobic fungi require oxygen, while anaerobic can grow without it.

What is an important characteristic of aerial hyphae?

They produce a variety of asexual reproductive spores.