Microbiology Lecture 1

Microbiology Lecture 1

• Microbiology is the study of microorganisms, including bacteria, viruses, fungi, protozoa, and algae.
• Microorganisms are essential for life on Earth, playing roles in decomposition, nutrient recycling, and maintaining human health.
• Some microbes are pathogenic (disease-causing), while others are beneficial, particularly in medicine, biotechnology, and pharmacy.
• Microorganisms exist in every ecosystem and are associated with all multicellular organisms, including humans.
• Many microorganisms are part of the normal flora (bacteria), most are harmless or helpful. Some cause diseases. These are called pathogens.
• Infectious diseases begin when microorganisms colonize the body (skin or mucous membranes) or are introduced into the bloodstream or internal organs.
• An infected organism may have its immune system eliminate the microbes or the microbes may multiply and cause infection and damage to tissue.
• The discovery of microorganisms was possible due to the invention of the microscope. Anton van Leeuwenhoek and Robert Hooke were key figures in microscopy.
• Subsequent advancements in the 17th century allowed for larger magnification by microscopes.
• The germ theory was developed and helped to reject the theory of spontaneous generation, which states that life can arise from non-living matter. Important figures are Louis Pasteur and Robert Koch.
• Modern microbiology emerged in the late 19th century and was influenced by improvements in staining techniques, sterilization, microscopy. Key figures include Joseph Lister and Alexander Fleming. Lister was influential in antiseptic surgery. Fleming developed penicillin.
• Prokaryotic organisms are bacteria, while eukaryotic organisms include fungi, protozoa, and helminths (e.g., humans),
• Prokaryotic and eukaryotic organisms differ structurally.
• Bacteria, archaea, and cyanobacteria are prokaryotic.
• Typical bacteria have shapes such as rods, spheres, and corkscrews.
• Atypical bacteria include mycoplasma, chlamydia, and rickettsia, which differ from typical bacteria in significant structural components or metabolic capabilities.
• Fungi are non-photosynthetic, eukaryotic organisms. Many are filamentous (molds) or unicellular (yeasts). They reproduce asexually, sexually, or both. Fungi cause a range of diseases from skin infections to systemic infections.
• Protozoa are single-celled, non-photosynthetic, eukaryotic organisms with various shapes and sizes. Many are free-living; others are significant parasites. Transmission occurs by ingestion or insect bites.
• Helminths are multicellular, eukaryotic organisms categorized as tapeworms, flukes, and roundworms. They are parasites that ingest/absorb body fluids or tissues to obtain nutrients. They cause diseases in humans.
• Viruses are obligate intracellular parasites,meaning they cannot reproduce outside a host cell. They consist of DNA or RNA molecules coated in protein, and they may have an envelope. Viruses cause many diseases.