Microbes in the Environment - Lab 2 PDF

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Microbes in the Environment...

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Results: Use the Colony Description (fig. 3) chart to fill in the data tables. Use a new line for each different colony type found on the environmental and body part samples. Table 1: Environmental sample

Area sampled: Lab sink HH 217 Incubated at 37C for 24 hours

Whole colony appearance Circular

Circular

Colony Descriptions Margin Elevation

Pigment

Entire

Raised

White

Entire

Raised

White

Table 2: Body sample

Area sampled: Bellybutto n Incubated at 37C for 24 hours

Whole colony appearance Circular

Circular

Colony Descriptions Margin Elevation

Pigment

Entire

Convex

White

Entire

Convex

White

Adapted from Cremins, J. (no date). Microbiology Lab Manual Custom MCC BIO 235. Pearson Custom Publishing, Boston, MA

Use the Broth Culture Patterns (fig. 4) chart to fill in the data table. Table 3: Broth Culture Growth Patterns (Y/N) Turbidity

Environmental Sample: Lab Sink Yes

Body Sample: Bellybutton Yes No

Flocculent Yes

Yes

Sediment Yes

Yes

Pellicle No

No

Ring No Color Colorless

Colorless

Conclusions 1. Which area had the most bacteria? Explain your answer. I think belly belly button sample, because based on the image obtained after isolation, we can see more colony than lab sink. This is the part we often ignore when personal hygiene, and so that navel also becomes a nest of germs. It is possible that the lab sink is cleaned regularly with detergent, so there is less bacteria. 2. Which environment had the most different types of bacteria? Explain your answer. I think belly belly button sample, because we can see colony has many sizes big, medium and small. In the third isolated area only the largest and smallest colony species can grow. 3.

Which technique, agar or broth, provided the most information? Explain your

answer. Nutrient agar provides us the most information because colonies of different bacteria look different on agar. In broth, we cannot identify the differences; it only shows the presence of bacteria growth.

Adapted from Cremins, J. (no date). Microbiology Lab Manual Custom MCC BIO 235. Pearson Custom Publishing, Boston, MA

Questions 1. Define and/or explain the use of the following: (a) Agar is a solid growth media. It contains a gelatinous colloidal extract of a red alga which is a mixture of polysaccharides. It is used as a solidification agent because it is not broken down by bacteria, contains no nutrients that can be used by bacteria, and yet is solid at temperatures used for most bacterial growth. (b) Broth is a liquid medium used to grow bacteria in laboratories. It contains various nutrients (meat, vegetables, or bones boiled in water). Broths can be used to determine growth patterns in a liquid medium and for certain types of inoculations and metabolic or growing large quantities of bacteria.

Critical Thinking 1. A description of colony morphology (shape) provides important information about an organism. What other features should you include? Morphology is the shape of an organism. Other features such as size, color, and optical characteristics such as shiny, opaque, etc. are also necessary. In addition, incubation temperature, time, type of growth medium, and sample source should be included. 2. Why is it necessary to complete the identification of a bacterium based on physiology rather than its morphology? Morphology only helps scientists find out the basic forms of bacteria. In biology, morphology is the study of the size, shape, and structure of bacteria, and microorganisms and of the relationships of their constituent parts. In contrast, physiology is the study of the functions of organisms and their parts. Based on the physiology of bacteria, scientists can identify the life-supporting functions and processes of bacteria, which allow bacterial cells to grow and reproduce. From there, scientists can find the method to inhibit the growth of bacteria.

Adapted from Cremins, J. (no date). Microbiology Lab Manual Custom MCC BIO 235. Pearson Custom Publishing, Boston, MA...