Mic Lecture1

Introduction to Microbiology Department of Applied Science King Saud University/ Community College By: Murad Sawalha

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What is Microbiology? Categories Why we study microbiology? Careers of microbiology The metric system

What is Microbiology? Micro means very small, can seen only by a microscope (an optical instrument used to observe very small object) ■ Microbiology: is the study of very small living unicellular organisms, these organisms called microorganisms or microbes. ■ Microorganisms are ubiquitous (they are virtually everywhere). ■ The discipline is just over a century old. ■ Has given rise to molecular biology and ■

Cont. Pathogens: Disease causing microorganisms (3% of microbes. ■ Non-pathogens: microorganisms that do not cause disease (vast majority). Some of these are beneficial to us & some have no effect on us at all. Microorganisms that help us called microbial allies. - Microorganisms that harm us called microbial enemies. ■

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Cellular microorganisms are divided into: 1) Eucaryotes: organisims having a true nucleus, such Algae, fungi, & Protozoa. 2) Procaryotes: organisims lacking a true nucleus, such as archaeans, & Bacteria. Viruses are not consider to be cells (a cellular), most scientists do not consider viruses to be living organisims, they consider them as infectious agents or infectious particles, rather than microorganisims.

Why study Microbiology (reasons)? We have, living on & in our bodies (e.g., on our skin & in our mouth & in our mouth) - 500 to 1000 different species of microorganisms live on and in our bodies. These microbes called our indigenous flora, mostly beneficial for us. ■ Some of the organisms that colonize our bodies are known as opportunistic ■

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Microorganisms are essential for life. - Example: Some microbes produce oxygen by the process known as photosynthesis. Many microorganisms are involved in the decomposition of dead organisms and the waste products of living organisms, they called decomposers or saprophytes. - Example: breakdown dead & dying organ materials (plants & animals) into nitrates, phosphates, and other chemical necessary for the growth of plants

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Some microorganism are capable of decomposing industrial wastes (oils for example). Many microorganisms are involved in elemental cycles (carbon, nitrogen, oxygen, sulfur, & phosphorus cycles). Algae and bacteria serve as food for tiny animals. Some microorganisms live in the intestinal tracts of animals, they aid in

Why study Microbiology (reasons)? Many microorganisms are essential in various food and beverage industries, while other are used to produce certain enzymes and chemicals. ■ Certain bacteria and fungi produce antibiotics that are used to treat patients with infectious diseases. ■ Microbes are essential in the field of genetic engineering. ■

Why study Microbiology (reasons)? For many years, microbes have been used as “cell models”. ■ Microorganisms cause two categories of diseases: infectious diseases and microbial intoxications ■