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Flashcards in Quiz 3 Deck (33)
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1
Q

Aflatoxins (6)

A

Flat-ringed planar compounds that can intercalate between the bases of DNA & act as mutagens

2
Q

Where are myxobacteria found? Gram positive or negative? Defining feature? (7A)

A
  • Gram-negative bacteria found in high-organic soils and decomposing plant material
  • Social bacteria
3
Q

Myxobacteria shape (7A)

A

Rod-shaped with a flexible cell wall

4
Q

Myxobacteria motility (7A)

A
  • Do not use flagella
  • Perform gliding motility that allows them to swarm on surfaces in a coordinated manner
  • Travel in ripples
5
Q

Myxobacteria life cycle (7A)

A
  • Upon starvation, vegetative cells will aggregate into fruiting bodies, within which a subpopulation differentiates into stress-resistant myxospores
  • When introduced to a new food source, the myxospores germinate & give rise to new cells which use gliding motility & divide via binary fission
6
Q

Myxospores (7A)

A

-Some genera of myxobacteria will have myxospores containined in sacs called sporangioles borne on stalks formed by vegetative cells

7
Q

Are Actinomycetes gram positive or negative? Aerobic or anaerobic? Defining feature? (7B)

A
  • Aerobic, gram positive microbes

- Form branching filaments

8
Q

Actinomycetes shape (7B)

A
  • Appear to be intermediate between bacteria & fungi
  • Resemble filamentous fungi with extensive, branching mycellium
  • Some genera give rise to condidospores
9
Q

Actinomycetes colonies (7B)

A
  • Form small, compact, leathery colonies
  • Usually consisting to two types of mycelia
  • –i) Form a very fine vegetative/submerged mycellium that grows into the subsrate which feeds
  • –ii) Form an aerial mycellium which is thicker and may give a powdery appearance as a result of condidospores
10
Q

Streptomyces (7B)

A
  • An important genera of Actinomycetes
  • Soil-dwelling
  • Major source of antibiotics
11
Q

Photosynthesis (7C)

A

Capture light energy and convert it to chemical energy

12
Q

Cyanobacteria (7C)

A
  • A type of photosynthetic bacteria
  • Performs oxygenic photosynthesis (provides oxygen)
  • Use chlorophylls
13
Q

Green and Purple Algae (7C)

A
  • Types of photosynthetic bacteria
  • Perform anoxygenic photosynthesis (do not provide oxygen) using other reduced compounds as sources of electrons
  • Use bacteriochlorophylls
14
Q

Accessory pigments (7C)

A
  • Phycobiliproteins & carotenoids
  • Absorb light energy and transfer it to the chlorophyll or bacteriochlorophyll
  • Can protect the microorganism from intense sunlight
15
Q

Green and purple sulfur bacteria (7C)

A
  • Oxidize certain inorganic sulfur compounds during photosynthesis
  • Obligate anaerobes – cannot tolerate any oxygen
  • Found in aquatic sediments exposed to light
16
Q

Green and purple non-sulfur bacteria (7C)

A
  • Facultative aerobes – do not require oxygen for growth, but grow better in its presence
  • Found in aquatic sediments exposed to light
17
Q

Succession (7D)

A

How one group of organisms succeeds another as conditions are created which select for them
—Ex: Like in a Winogradsky column

18
Q

What does a TTC Deep test for? What does TTC stand for? (8A)

A
  • Triphenyl Tetrazolium Chloride
  • Tests for motility
  • No growth will occur if organism is obligate anaerobe
19
Q

What does a TSI Slant test for? What does TSI stand for? (8A)

A
  • Triple Sugar Iron Agar
  • –Contains Lactose, Sucrose, and Glucose
  • Tests for acid or alkaline
  • –Yellow: Acid (fermentation)
  • –Red: Alkaline (non-fermentation)
  • Black color indicated H2S production
20
Q

What does growing a microbe in Tryptone Broth indicate? What must you add after incubation to complete test? (8A)

A

-Must add Kovak’s Reagent to determine if Indole is produced

21
Q

What does Bile Esculin Broth indicate? (8A)

A
  • Contains bile salts, which inhibit Streptococcus from growing
  • Tests ability to hydrolyze esculin to esculitin & glucose
22
Q

What does MacConkey agar select for? What does it differentiate? (8A)

A
  • Selectivity: Crystal violet inhibits gram positive growth
  • Differentiable: Lactose with neutral red dye in media; Lactose fermenters appear pink, Nonfermentors are yellow or colorless
23
Q

What does Ashby’s N-Free Agar select for? (8A)

A

-Selective for microorganisms able to fix atmospheric N2 for growth

24
Q

What are the two non-selective types of media used in this lab? (8A)

A

i) TSA - Tryptic Soy Agar

ii) LB - Luria Bertani

25
Q

What does CNA stand for? What does it select for? Differentiate for? (8A)

A
  • Colistin-Nalidixic Acid Agar (with blood)
  • Blocks gram negative organisms from growth – disrupts lipids and LPS in gram negative outer membrane
  • –Note: Bacillus normally does not grow on CNA even though it is gram positive
  • Differential: Blood detects hemolytic activity
26
Q

Psuedomonas Enrichment Benzoate Medium (8A)

A

-Psuedomonas can convert hydroxybenzoate in the medium to Acetyl-CoA & Succinate, which can be used in the TCA cycle

27
Q

What does PAF stand for What is it selective for? What does it differentiate? (8A)

A
  • PAF: Psuedomonas Agar F
  • Non-selective
  • Differential: Color change to fluoresce in the presence of Pyoverdin
28
Q

What does PAP stand for? What is in selective for? What does it differentiate? (8A)

A
  • PAP: Psuedomonas Agar P
  • Non-selective
  • Differential: Color change to blue in presence of pyocyanin
29
Q

What does MSA stand for? What is it selective for? What does it differentiate? (8A)

A
  • MSA: Mannitol Salt Agar
  • Selective: High salts selects for Staphylococcus
  • Deifferential: Mannitol fermentation (yellow: acid fermentation)
30
Q

Blood Agar selectivity and differentiability (8A)

A
  • Non-selective
  • Differential: Hemolysis
  • Beta hemolysis: Complete (clear are around colonies)
  • Alpha hemolysis: Partial, greenish
  • Gamma hemolysis: No hemolysis
31
Q

DNAse Test with Methyl Green (8A)

A
  • Selective: Methyl green inhibits some gram positive bacteria
  • Differential: Clearing indicated DNA hydrolysis / DNAse positive
32
Q

Oxidase Test (8A)

A
  • Tests for cytochrome oxidase

- Oxidation indicator produces purple color

33
Q

Catalase Test (8A)

A
  • Hydrogen peroxide detects presence of catalase

- –Bubble formation means catalase positive