Science of Microbes Activity 4 Observing Different Microbes

Science of Microbes Activity 4 Observing Different Microbes Power. Point Slides and Notes by Nancy Moreno, Ph. D, and Barbara Tharp, MS Activity by Nancy Moreno, Ph. D, Barbara Tharp, MS, Deanne Erdmann, MS, Sonia Rahmati Clayton, Ph. D, and James Denk, MA Bio. Ed Online

Materials for Each Group of Four Students Bio. Ed Online

Safety Considerations n Follow all instructions. n Begin investigation only when instructed. n n n Do not taste or smell unknown substances. Report accidents or spills. Wash hands thoroughly after the investigation. n Handle slides and cover slips carefully. n No eating or drinking allowed. Bio. Ed Online

Engage Students by Asking… n Can you name a microbe? n Have you ever seen a microbe? n Are there different kinds of microbes? n Do all microbes look alike? n What determines whether an organism is considered a microbe? Bio. Ed Online Bacteria that cause tuberculosis. (photo courtesy of the National Institute of Allergy and Infectious Diseases)

Prepare Slides of Microbes to Observe n n n Follow the instructions on the Slide Preparation Cards to observe and compare different kinds of microbes. n Bacteria n Yeast n Paramecia Draw what you observe. Look for similarities and differences. Bio. Ed Online

Let’s Talk About Bacteria n Shape n Rod-shaped (in yogurt). n n n Other kinds are rounded (spherical) or spiral. Rod-shaped Size n Very small (1– 5µm). n Small size makes it difficult to observe internal components with a light microscope. Prokaryotes n Simple cell structure. n No central nucleus surrounded by a membrane. Bio. Ed Online Spiral Spherical

Let’s Talk About Baker’s Yeast Cells n Shape n n More or less rounded (spherical). Can reproduce by generating “bud cells” from a parent cell (see arrow). Size n Approximately 10µm in diameter. Eukaryotes n More complex cell type. n Hereditary material in a cell nucleus surrounded by a membrane. Baker’s Yeast (Saccharomyces cerevisiae). (Photo courtesy A. E. Wheals, Ph. D. , ©University of Bath, U. K. ) Bio. Ed Online

Let’s Talk About Paramecia n n n Shape n “Slipper-shaped. ” n Long “oral groove” directs food to a place where it can be incorporated into the cell (see arrow). n External cilia for locomotion and movement of food. Size is approximately 250 µm. Eukaryotes n Cell structure with many internal components. n Cell nucleus surrounded by a membrane. Paramecium (Photo courtesy Ron Neumeyer, © Microimaging Services) Bio. Ed Online

Microscopic Pond Life n n How many different kinds of organisms can you observe? Hydra In what ways are the organisms similar or different? n Shape Daphnia n Size n Movement n Color Photos courtesy © BIODIDAC Bio. Ed Online Euglena Spirogyra (green algae)