Module 5 + 6 Labs

Terms for desc a media recipe and its ingredients

rich, defined, selective, inhibitor, substrate, indicator, and differential

Examples of Carbon Sources

-ose suffix, digest, extract, infusion

Examples of Nitrogen Sources

-ine/-one/-in/-ine suffix, digest, extract, infusion, NH4, NO3, NO2

Rich

Media that contain digests, extracts, or infusions

Defined

Media that are missing these ingredients (carbon + nitrogen source) and instead might have glucose/dextrose (for carbon) or ammonium (for nitrogen)

Inhibitor

include molecules that actually kill certain bacteria

• Selective

Selective

they select for only certain species to grow.

• are in media w/an inhibitor

Some media can be both __ and _

selective and differential

Substrate-Indicator Combo

Another option for media

• Are considered differential

Substrate

is a molecule we are testing to see if the organism can use or break it down

Indicator

allows us to visibly see that the organism is using the substrate.

To grow bacteria, you MUST INCLUDE

carbon source and a nitrogen source

1. Is PEA rich or defined? How do you know?

PEA is rich because of the pancreatic digest of casein and the papaic digest of soybean meal. Rich media contain digests, extracts, and infusions; while defined doesn’t.

2. What is the carbon source in this media? What is the nitrogen source in this media?

The carbon and nitrogen both come from the digests since those are made of other organisms that would have contained carbon and nitrogen molecules. 

3. Is PEA selective or differential or both? How do you know?

PEA is selective because it contains an inhibitor (phenylethyl alcohol), which kills gram negative species.

1. Is MSA rich or defined?

MSA is rich due to the proteose peptone

2. MSA is

both selective and differential due to the NaCl, phenol red, and the mannitol sugar added