Ex. 2-2; 2-3 Flashcards
Colony
visible mass of cells formed from one cell as it divides and accumulates.
What environmental factors influence the morphology of colonies?
- nutrient availability (medium)
- temperature
- incubation time
What are the seven basic categories of colony morphology?
- Size
- Shape
- Margin
- Surface
- Texture
- Elevations
- Color & Optical properties
Define size in regards to colony morphology.
a measurement of the colony’s dimensions - the diameter if circular or length and width if shaped otherwise.
What terms are associated with shape in regards to colony morphology?
- round (circular)
- irregular
- punctiform (tiny, pinpoint)
What terms are associated with margin in regards to colony morphology?
- entire (smooth, with no irregularities)
- undulate (wavy)
- lobate (lobed)
- filamentous (unbranched strands)
- rhizoid (branched-like roots)
- echinulate (spiny)
What terms are associated with surface in regards to colony morphology?
- smooth
- rough
- wrinkled (rugose)
- shiny
- dull
What terms are associated with texture in regards to colony morphology?
- moist
- mucoid (sticky)
- butyrous (buttery)
- dry
What terms are associated with elevation in regards to colony morphology?
- flat
- raised
- convex
- pulvinate (very convex)
- umbonate (raised in the center)
What terms are associated with optical properties in regards to colony morphology?
- opaque (you can’t see through it)
- translucent (light passes through)
What are agar slants typically used for?
they are useful primarily as media for cultivation and maintenance of stock cultures.
What additional terms are used to describe growth patterns on slants?
- Filiform
- pigmented
- friable
- spreading edge
- translucent/transparent
filiform
growth that is dense and opaque with a smooth edge
pigmented
colored
friable
growth that is dry and crusty
spreading edge
growth that spreads at the edge (spreading margin)
What are two important factors influencing bacterial growth?
- incubation time
2. temperature
Are slants normally inoculated with pure or mixed cultures?
Pure
What are the advantages and disadvantages of using a slant?
Advantages include: providing bacterial storage over extended periods of time with a minimal risk of contamination or desiccation; useful in the identification of of bacteria by characteristic patterns of movement.
Disadvantages include: organisms are less observable and accessible than those in petri dishes.
How will the arrangement of the staphylococcis epi. in broth differ from the arrangement in the slant culture?
Broth will show turbidity, pellide or sediment while arrangement in slant culture will show colonies and shape/arrangement/individual colonies.
What microbes did we view in slants? Describe their growth patterns.
- Alcaligenes faecalis - white, spreading edge
- Bacillus subtilis - light tan, rhizoid
- Staphylococcus epidermidis - white, entire smooth edge
- Serratia marcescens - red, entire smooth edge
- Micrococcus luteus - yellow, beaded or filiform, entire smooth edge
- Pseudomas aeruginosa - green, spreading margin
