Labs 9-12 Flashcards Preview

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Flashcards in Labs 9-12 Deck (16):
1

Spore Staining

Endospores are not easily penetrated by stains:
- Heat applied while staining with malachite green, not removed by subsequent washing with decolorizing agents or water
- Heat (mordant) helps pigment penetrate deeper inside of the cell

2

Endospore Locations

- Central
- Terminal (either end)
- Lateral (side)
Knowing if these are present helps in classifying and identifying certain types of bacteria (Bacillus, Clostridia)

3

Wet Mount Preparation

- Place a drop of liquid, onto or containing specimen, onto microscope slide
- Touch the liquid with the edge of a coverslip, holding slip at a 45 degree angle
- Drop coverslip onto the slide
- Useful for viewing still-living organisms; easy to prepare

4

Brownian Motion (Streaming)

Water molecules are colliding with another material or an organism, giving it the appearance of movement (shaking or vibrating due to water current)

5

True Motility

- In microbes, due to flagella or cilia
- From a medical standpoint, knowing this tells the medical staff whether an infectious agent is localized or capable of spreading

6

Presence of Flagella

This increases the ability of bacteria to cause disease because it allows them to go wherever they want, spreading the disease as they go

7

Monotrichous

Single flagellum at one end

8

Amphitrichous

Single flagellum at each end

9

Lophotrichous

A tuft of many flagella at one end

10

Peritrichous

Flagella located on many sides

11

Arrangement of Flagella

This helps microbiologists characterize and classify bacteria

12

Complex (nutrient) Medium

Contains rich extracts of meat or plants that supply amino acids, nucleotide bases, vitamins, and other growth factors; exact composition and amounts are not known; used to cultivate an organism with unknown nutritional requirements

13

Defined Medium

Specific nutritional requirements for an organism to grow are known, so the specific chemical composition of this medium are also known; individual components are weighed out exactly

14

Liquid (broth) Cultures

Used to grow large volumes of bacteria

15

Agar

Used to isolate colonies on a solid medium:
- First used by Robert Koch
- Melts at 100' C and solidifies at 45' C
- Cannot be used as an energy source by most bacteria
- 1.5% concentrations to solidify (.4% for motility studies)
- Sterilized using an autoclave: media heated to 121' C for at least 15 minutes at 15 psi of steam pressure

16

Colony Characteristics

- Configurations
- Margins
- Elevations
- Color: S. marcescens - red; S. epidermidis - white