7 Microbiology and Protista Lab
Lab Objectives
At the conclusion of the lab, the student should be able to:
- Describe the basic structures of a bacterial cell.
- State the three domains of life
- Name the shape of a given bacteria specimen
- State the domain of cyanobacteria
- Be able to identify the cyanobacteria examples viewed in lab
- State the domain of the protista
- Be able to identify the green algae examples viewed in lab and know if they are colonial or filamentous
- Be able to recognize the protista specimen viewed in lab
- Identify protista as photosynthetic or heterotrophic
Download a PDF of the lab to print.
Part 1: Prokaryotes
Procedure
- Access the page “Reading: Prokaryotes.”
- We will not be using any live bacteria specimens. Instead, watch this video about aseptic technique. This technique is important to avoid microorganism contamination.
Questions
- Answer the questions below based on the video.
- What two tools are most commonly used to transfer bacteria?
- With the Bunsen burner, what color is the hottest flame?
- How are the inoculation tools sterilized?
- When transferring bacteria from a liquid culture to a Petri plate, why do you turn the plate while spreading the bacteria?
- When transferring bacteria from a Petri plate to a stab culture, how many times should you stab the needle?
- When transferring bacteria into a liquid tube do you flame the mouth of the tube before inoculation, after inoculation, or both?
- Skip to the end of the lab activity where it says “Prepared slides of typical bacteria” and view the prepared slides of bacterial shapes available in the laboratory.
- Draw a picture of the coccus-shaped bacteria.
- Draw a picture of the bacillus-shaped bacteria.
- Draw a picture of the spirillum-shaped bacteria.
- View the prepared slides of cyanobacteria available in the laboratory. Although they are single-celled, note how they form colonies and attach to one another
- What is the function of the heterocyst in the Anabaena?
- If the Oscillatoria is moving, describe the movement quality below.
- Which cyanobacteria species form chains? Which cyanobacteria species form clumps?
Part 2: Protista
Procedure
- Access the page “Reading: Protists.”
- Watch this video.
Questions
- View the Euglenozoans specimens available.
- What color is the euglena?
- What structure does the euglena use to move?
- Can you see any internal chloroplasts?
- Can you see the red eyespot? It does not give the organism vision but rather allows it to sense the presence of light.
- Trypanosoma sp. cause African sleeping sickness. (This disease was discussed in the video.)
- What part of the human body does the Trypanosoma invade?
- What structure does the Trypanosoma use to move?
- How does the Trypanosoma avoid being killed by the white blood cells?
- Can African sleeping sickness cause death?
- View the diatom specimens available.
- What material is found in the cell wall of the diatoms?
- Are the organisms single or multi-cellular?
- View