Quiz 1 Flash Cards

Aseptic Technique

The collective methods of obtaining and maintaining a pure culture.

Pure Culture

A culture containing only one species of microorganism.

Contaminant

Any other introduced microorganism introduced to the pure culture.

Contaminated/Mixed Culture

Pure culture + the contaminant.

Media

Substance where the microorganism is grown and maintained,

Media Examples

• Agar Plate

• Agar Deep Tube

• Broth

• Agar Slant

Sterilization

Goal to wipe out everything.

Disinfection

Goal is reducing a broad range of microbes.

Sanitization

Goal is reducing bacteria specifically.

Thermal Death Time

Length of time required to kill all the microorganisms in a liquid suspension at a designated temperature.

Thermal Death Point

Lowest temperature at which all of the microorganisms in a liquid suspension are killed within ten minutes.

Autoclaving

Steam Heat under Pressure to prevent boiling of heat sensitive liquids

Tyndallization

Successive boiling to heating

Tube Disposal: Solid

Cap off tube upside down.

Tube Disposal: Liquid, Screw Cap

Cap off, remain upright

Tube Disposal: Liquid, No Screw Cap

Cap on, remain upright

Growth Factors: Physical

• Temperature

• Incubation

Growth Factor: Chemical

• pH

• Minerals

• Energy Source

• Amino acids

• Vitamins

• Minerals

• Water

Fastidious Organisms

• Requires a complex set of chemical factors

• The more complex the more fastidious

• 
  

Heat Fixing

Kill the bacteria, stick it to the slide.

Gram-Stain:

Purple: Positive

Pink: Negative

Why use Agar?

• Easily melts and solidifies

• Can manipulate the hardness

• Autoclavable

• Acts as check for contamination

• Allows for creation of homogenous cultures

Why slants over plates?

• Less contamination risk

• Faster dehydration rate

• Less media consumption

Agar Deeps

• Anaerobic conditions

• can change the density of media to test motility

Types of Broth Growth

• Turbid

• Pellicle

• Sediment

• Button

• Flocculent

• Pellet/Myocorrhizal

Type of Broth Growth/Definitions

• Pellicle – mat-like growth at the air – liquid interface

• Sediment – loose clumpy growth at bottom of broth

• Button – Hard, resistant growth at bottom of tube

• Flocculent – Evenly distributed clumping

• Pellet/Mycorrhizal – Usually fungal clumped

• Turbid - cloudy/milky look to broth

Gram Positive

• Thicker cell wall due to greater number of peptidoglycans

• Purple

Gram Negative

• Thinner Cell Wall

• Extra membrane; a lipid bilayer

• Pink

Gram Staining Techniques: Fluids (in order)

1. Crystal Violet

2. Iodine

3. Ethanol

4. Basic Fuchsin

Gram Staining: Crystal Violet

1. Primary Stain

2. 60 seconds’

3. Dyes the bacteria purple

4. G+: Purple

5. G-: Purple

Gram Staining: Iodine

1. Mordant (Binds to crystal violet)

2. 60s

3. G+: Purple

4. G-: Purple

Gram Staining: Ethanol

1. Decolorizer

2. 30 seconds

3. G+: Purple

4. G-: Clear

Gram Staining: Fuschin

1. Counter stain

2. 60 s

3. G+: Purple

4. G-: Pink

Dyes everything pink, shows only on G-/

Slants vs. Deeps

• Slants: Most often used for growth and storage of pure cultures

• Deeps: used too measure motility, oxygen dependency, and metabolic end products

Terms of Growth

• Pellicle

• Turbid

• Sediment

• Mycelia

Pellicle

• Cells grown on surface of broth

Turbid

• Cloudiness/opaqueness

Sediment

• Growth settled on the bottom of the tube

Mycelia

Clumps of cells floating in the broth

Range of Colonies on Plate

30-300

Why do we T-streak?

• To isolate colonies

True or False: It is okay to use controls on a different slide from your unknown culture if you are careful

False

Motility

Movement caused by action of flagella

Positive chemotaxis

Motility towards a favorable environment

Negative Chemotaxis

Motility away from a less favorable or harmful environment

Flagella

• Hollow tubes made of the protein flagellin

Polar flagellation

• Cells with flagella inserted only in the ends of the cell.

Peritrichous Flagellation

Cells with flagella inserted all over the cell

Name?

Peritrichous

Name?

Lophotrichous

Endospore

Structure formed on the inside of the cell

Vegetative Cells

Cells lacking endospores

Sporangium

the rest of the cell surrounding the mature endospore

Name?

Monotrichous

Bacterial Endospores

• Most G+ rods

• central or terminal location

• absence does not equal incapability

• spore formation helps in identification

• resistant to environmental stressors

• resist staining due to keratin