Quiz 3 Flashcards
(33 cards)
Aflatoxins (6)
Flat-ringed planar compounds that can intercalate between the bases of DNA & act as mutagens
Where are myxobacteria found? Gram positive or negative? Defining feature? (7A)
- Gram-negative bacteria found in high-organic soils and decomposing plant material
- Social bacteria
Myxobacteria shape (7A)
Rod-shaped with a flexible cell wall
Myxobacteria motility (7A)
- Do not use flagella
- Perform gliding motility that allows them to swarm on surfaces in a coordinated manner
- Travel in ripples
Myxobacteria life cycle (7A)
- 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
Myxospores (7A)
-Some genera of myxobacteria will have myxospores containined in sacs called sporangioles borne on stalks formed by vegetative cells
Are Actinomycetes gram positive or negative? Aerobic or anaerobic? Defining feature? (7B)
- Aerobic, gram positive microbes
- Form branching filaments
Actinomycetes shape (7B)
- Appear to be intermediate between bacteria & fungi
- Resemble filamentous fungi with extensive, branching mycellium
- Some genera give rise to condidospores
Actinomycetes colonies (7B)
- 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
Streptomyces (7B)
- An important genera of Actinomycetes
- Soil-dwelling
- Major source of antibiotics
Photosynthesis (7C)
Capture light energy and convert it to chemical energy
Cyanobacteria (7C)
- A type of photosynthetic bacteria
- Performs oxygenic photosynthesis (provides oxygen)
- Use chlorophylls
Green and Purple Algae (7C)
- Types of photosynthetic bacteria
- Perform anoxygenic photosynthesis (do not provide oxygen) using other reduced compounds as sources of electrons
- Use bacteriochlorophylls
Accessory pigments (7C)
- Phycobiliproteins & carotenoids
- Absorb light energy and transfer it to the chlorophyll or bacteriochlorophyll
- Can protect the microorganism from intense sunlight
Green and purple sulfur bacteria (7C)
- Oxidize certain inorganic sulfur compounds during photosynthesis
- Obligate anaerobes – cannot tolerate any oxygen
- Found in aquatic sediments exposed to light
Green and purple non-sulfur bacteria (7C)
- Facultative aerobes – do not require oxygen for growth, but grow better in its presence
- Found in aquatic sediments exposed to light
Succession (7D)
How one group of organisms succeeds another as conditions are created which select for them
—Ex: Like in a Winogradsky column
What does a TTC Deep test for? What does TTC stand for? (8A)
- Triphenyl Tetrazolium Chloride
- Tests for motility
- No growth will occur if organism is obligate anaerobe
What does a TSI Slant test for? What does TSI stand for? (8A)
- 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
What does growing a microbe in Tryptone Broth indicate? What must you add after incubation to complete test? (8A)
-Must add Kovak’s Reagent to determine if Indole is produced
What does Bile Esculin Broth indicate? (8A)
- Contains bile salts, which inhibit Streptococcus from growing
- Tests ability to hydrolyze esculin to esculitin & glucose
What does MacConkey agar select for? What does it differentiate? (8A)
- Selectivity: Crystal violet inhibits gram positive growth
- Differentiable: Lactose with neutral red dye in media; Lactose fermenters appear pink, Nonfermentors are yellow or colorless
What does Ashby’s N-Free Agar select for? (8A)
-Selective for microorganisms able to fix atmospheric N2 for growth
What are the two non-selective types of media used in this lab? (8A)
i) TSA - Tryptic Soy Agar
ii) LB - Luria Bertani
