Microbiology Lab Report #3 Spring 2015

Microbiology Lab Report #3 – Spring 2015

In this report you will draw and describe the appearance of growth on/in each broth and slant you inoculated. Broth cultures should be observed both before and after mixing.

SLANTS: Growth on your slants should be described by color and amount (abundant, sparse, absent). Draw and describe your observations in the appropriate boxes in the table below.

BROTHS

The pattern of growth in a broth should be observed before any mixing, and can be described (as shown in figure 2-37 on page 73) as:

Flocculent Sediment Ring Pellicle Uniform fine turbidity

Amount of growth in broth can be described by its degree of cloudiness (turbidity), using a qualitative scoring system:

+++ means ‘very turbid’ ++ means ‘somewhat turbid’ + means ‘barely turbid’ 0 means not turbid

Observe the amount of growth before, and then after complete mixing.

Fill out the table below for each of your inoculated tubes., and then answer the questions that follow.

Medium Inoculated Source Nutrient Agar Slant Nutrient Broth Appearance S. epidermidis NA Slant

S. epidermidis NB

S. epidermidis NA Plate

NOT DONE Questions:

1. Considering the cultures used to inoculate each medium in this exercise, how many different microbial types should you expect to see in/on each medium?

2. You were asked to describe differences in the appearance of growth in each culture, if present. In which medium was this the most difficult to determine? What made this difficult?

3. Did you notice a difference in density (turbidity) of growth in NB tubes inoculated from NB versus NA slants? Whether or not you did, suggest a possible reason why a difference might occur.

4. Match the following: ______Flocculent a. Evenly cloudy throughout

______Sediment b. Growth at top around the edge

______Ring c. Growth on the bottom

______Pellicle d. Membrane at the top

______Uniform fine turbidity e. Suspended chunks or pieces