Ex. 2-2; 2-3

Question 1

Colony

Answer 1

visible mass of cells formed from one cell as it divides and accumulates.

Question 2

What environmental factors influence the morphology of colonies?

Answer 2

• nutrient availability (medium)
• temperature
• incubation time

Question 3

What are the seven basic categories of colony morphology?

Answer 3

1. Size
2. Shape
3. Margin
4. Surface
5. Texture
6. Elevations
7. Color & Optical properties

Question 4

Define size in regards to colony morphology.

Answer 4

a measurement of the colony’s dimensions - the diameter if circular or length and width if shaped otherwise.

Question 5

What terms are associated with shape in regards to colony morphology?

Answer 5

• round (circular)
• irregular
• punctiform (tiny, pinpoint)

Question 6

What terms are associated with margin in regards to colony morphology?

Answer 6

• entire (smooth, with no irregularities)
• undulate (wavy)
• lobate (lobed)
• filamentous (unbranched strands)
• rhizoid (branched-like roots)
• echinulate (spiny)

Question 7

What terms are associated with surface in regards to colony morphology?

Answer 7

• smooth
• rough
• wrinkled (rugose)
• shiny
• dull

Question 8

What terms are associated with texture in regards to colony morphology?

Answer 8

• moist
• mucoid (sticky)
• butyrous (buttery)
• dry

Question 9

What terms are associated with elevation in regards to colony morphology?

Answer 9

• flat
• raised
• convex
• pulvinate (very convex)
• umbonate (raised in the center)

Question 10

What terms are associated with optical properties in regards to colony morphology?

Answer 10

• opaque (you can’t see through it)

- translucent (light passes through)

Question 11

What are agar slants typically used for?

Answer 11

they are useful primarily as media for cultivation and maintenance of stock cultures.

Question 12

What additional terms are used to describe growth patterns on slants?

Answer 12

1. Filiform
2. pigmented
3. friable
4. spreading edge
5. translucent/transparent

Question 13

filiform

Answer 13

growth that is dense and opaque with a smooth edge

Question 14

pigmented

Answer 14

colored

Question 15

friable

Answer 15

growth that is dry and crusty

Question 16

spreading edge

Answer 16

growth that spreads at the edge (spreading margin)

Question 17

What are two important factors influencing bacterial growth?

Answer 17

1. incubation time

2. temperature

Question 18

Are slants normally inoculated with pure or mixed cultures?

Answer 18

Pure

Question 19

What are the advantages and disadvantages of using a slant?

Answer 19

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.

Question 20

How will the arrangement of the staphylococcis epi. in broth differ from the arrangement in the slant culture?

Answer 20

Broth will show turbidity, pellide or sediment while arrangement in slant culture will show colonies and shape/arrangement/individual colonies.

Question 21

What microbes did we view in slants? Describe their growth patterns.

Answer 21

1. Alcaligenes faecalis - white, spreading edge
2. Bacillus subtilis - light tan, rhizoid
3. Staphylococcus epidermidis - white, entire smooth edge
4. Serratia marcescens - red, entire smooth edge
5. Micrococcus luteus - yellow, beaded or filiform, entire smooth edge
6. Pseudomas aeruginosa - green, spreading margin