Bacterial Structure Mary Jewel Duag UPHSD – Graduate School Advanced Microbiology and Parasitology Table of contents 01 02 Diversity of Prokaryotes What is a Bacterium? 03 A Typical Bacterial Cell When you hear the word bacteria, what comes into mind? Diversity of Prokaryotes ● ● Prokaryotes = unicellular organisms Classified in Two Kingdoms – archaebacteria and eubacteria Archaebacteria: Often the extremists There are three types of archaebacteria that live mainly in extreme habitats where there is usually no free oxygen available. • Eubacteria: The heterotrophs • • • • This includes prokaryotes that live in more hospitable places that archaebacteria inhabit and that vary in nutritional needs. They live almost everywhere and use organic molecules as a food source. Some bacterial heterotrophs are parasites, obtaining their nutrients from living organisms. Others, are saprophytes, which are organisms that feed on dead organisms or organic wastes. Eubacteria: Photosynthetic autotrophs • • These eubacteria live in places with sunlight because they need light to make the organic molecules that are their food. Cyanobacteria are photosynthetic autotrophs. Cyanobacteria, such as Anabaena, have a bluegreen color. Eubacteria: Chemosynthetic autotrophs • • • These bacteria make organic molecules that are their food. The chemosynthetic bacteria do not obtain the energy they need to make food from sunlight. They break down and release the energy of inorganic compounds containing sulfur and nitrogen in the process called chemosynthesis. What is a Bacterium ? The Structure of Bacteria Identifying Bacteria ● Gram staining = technique that distinguishes two groups of bacteria because the stain reflects a basic difference in the composition of bacterial cell walls. Identifying Bacteria Thank You!
