BIO 101 Lab 04, Prokaryotes and Eukaryotes GENERAL BIOLOGY I

BIO 101 Lab 04: Prokaryotes and Eukaryotes Notification: If you have a disability that makes it difficult to complete this lab, please contact your instructor. Please provide your instructor a copy of the Memorandum of Accommodation (MOA) from NVCC Disability Support Services. Objectives:  Identify the general shapes of common bacteria  Describe the diversity of prokaryotic and eukaryotic microorganisms  Master the use of the light microscope Background: Microorganisms are organisms that require the use of a microscope to view and include bacteria, archaea, and most protists. Microorganisms are an integral part of our lives as humans and in the greater ecosystems of the world. They form symbiotic relationships with plants and animals and recycle nutrients in the environment. They even produce the majority of the oxygen you breathe. For example, cyanobacteria are photosynthetic bacteria that live in moist soils and in aquatic environments. Microorganisms are extremely diverse in their morphologies, metabolisms, and environments. A good rule of thumb is if there is an inorganic or organic material on Earth, there is a microorganism that can metabolize it. If there is a specific environmental condition on Earth there is a microorganism that has evolved to live or survive there. Microorganisms that have evolved to live in the most extreme environments typically are members of the Archaea domain. Bacteria and Archaea are often referred to as prokaryotic organisms, because they lack a nucleus. This is to be compared to eukaryotes, such as protists, that possess nuclei. Through the view of evolution all bacteria have a single common ancestor and archaea, such as Halobacterium and methanogens, have a separate common ancestor. In comparison among the three domains (Bacteria, Archaea, and Eukarya), the archaea biochemistry (inner metabolic functions) is more similar to eukaryotes than it is to bacteria. Protists are a collection of eukaryotic organisms. Some have movement and predatory (animal-like) qualities (protozoans), such as euglena and amoeba. Some protists have plant-like qualities, such as algae. Some microorganisms are pathogenic, meaning they can cause disease or illness. These pathogenic microorganisms can be prokaryotic, such as bacteria, or single celled eukaryotic organisms. Some species of the bacteria E. coli, for example, can cause food poisoning. Trichomonas vaginalis, Giardia lamblia, and Trypanosoma brucei are parasitic protozoan protists, and each are leading causes of disease in humans. Not all protists are parasitic, as diatoms are the major components of phytoplankton in nutrient rich coastal waters. Diatoms form a major portion of the nutrients towards the bottom of the food chain. The three major shapes of bacteria are coccus (round), bacillus (rod-shaped), and spirillum (coiled-spring shaped). Other bacteria shape include vibrio (comma shaped) and neisseriae BIO 101 Lab 04: Prokaryotes and Eukaryotes 1 To submit this assignment, students will complete the Lab Worksheet on pages 5-8, then upload their completed document as a DOC or PDF file in Canvas (paired coffee bean shaped). Bacteria can be observed as individual cells or as groups/clumps of cells. In this lab you and your group will observe live and prepared samples of microorganisms from all three domains of life. This will allow you to gain greater mastery over the use of the light microscope and view the varied morphologies of the microbe world. Materials:  Internet Safety: Follow all standard laboratory safety procedures. Microscopes are to be always carried with two hands. When in use, microscope cords are to be kept on the bench tops and NOT hanging from the bench where they can be accidently pulled by yourself or other students. Lab coats are not to be worn outside of the lab. Procedure: Data Collection 1. Morphology of Bacteria: Observe the images of the bacterial specimens below. Use the Background information to determine which image shows bacteria with the coccus shape, the bacillus shape, and the spirillum shape. In Table 1 of the Data Analysis and Synthesis Questions section draw the three shapes of bacteria as you see them in the images. BIO 101 Lab 04: Prokaryotes and Eukaryotes 2 To submit this assignment, students will complete the Lab Worksheet on pages 5-8, then upload their completed document as a DOC or PDF file in Canvas 2. Cyanobacteria: Observe the images of the cyanobacterial specimens below. Use the internet to search for images of Oscillatoria and Anabaena to determine which of the images below corresponds to each cyanobaterial species. In Table 2 of the Data Analysis and Synthesis Questions section draw Oscillatoria and Anabaena as you see them in the images. 3. Protists (Algae): Observe the images of the algae protists below. Use the internet to search for images of Spirogyra, Volvox, and Diatoms to determine which of the images below corresponds to each protist group. In Table 3 of the Data Analysis and Synthesis Questions section draw Spirogyra, Volvox, and Diatoms as you see them in the images below. BIO 101 Lab 04: Prokaryotes and Eukaryotes 3