Unit 5.2: Growing microbes in the lab

What is liquid media used for?

Liquid media is used to grow large amounts of bacteria

What is solid media used for?

Solid media is used to isolate colonies in mixed samples

What is Agar used for?

Agar is used as a solidifying agent

What is chemically defined media?

Chemically defined media is when the media is specifically tailored for a microbe. Complicated and time-consuming to make

What is an example of chemically defined media?

Chemically defined media example: EZ medium

What type of bacteria is chemically defined media for?

Chemically defined media is for autotrophic bacteria

What is complex media?

Complex media is when the media uses a vague mixture of extracts. Complex media is more commonly used.

What is an example of complex media?

Complex media example: nutrient broth

What type of bacteria is complex media used for?

Complex media is used for chemoheterotrophs

What is selective media?

Selective media suppresses the growth of the unwanted bacteria and encourages the growth of the wanted bacteria

What is differential media?

Differential media uses a chemical to visually distinguish one species from another

What does selective Mannitol salt agar do?

Selective Mannitol salt agar’s salt concentration only lets halotolerant bacteria (Staphylococcus) grow

What does differential Mannitol salt agar do?

Differential Mannitol salt agar produces acids that differentiates the species of Staphylococcus

What does Blood Agar show?

Blood Agar shows hemolysis

What do the three hemolysis look like on Blood Agar?

Beta Hemolysis looks like a completely clear background

Alpha Hemolysis looks like a green background

Gamma hemolysis is no hemolysis at all

What is a short term method for preserving bacterial cultures?

Short term method: Refrigeration (2-4 weeks)

What are the two long term methods for preserving bacterial culture?

1. Deep freezing: culture of microbes are placed in a suspending liquid and frozen (6-12 months)

2. Lyophilization: a suspension of microbes are quickly frozen then water is removed by a high vacuum, giving a powder (few years)

Where must viruses be grown in?

Viruses must be grown in:

• Vivo: whole organisms

• Vitro: in cells in an artificial environment

What are the three ways to grow Animal Viruses?

1. Living animals (mice)

2. Embryonated eggs

3. Cell cultures (immortal cells)

Describe the steps of growing a Bacteriophage

1. Start with a lawn of bacteria

2. Phage (bacteria virus) is added to the plate

3. Phages will cause lysis on susceptible bacteria