Introduction to Microbiology Opto 435 Mrs. Amany Niazy

Microbiology Biology  the study of living organisms. Micro  very small (needs a microscope to be see). Microbiology  is the study of very small living organisms. Microorganism A microorganism is a very small living organism found in every ecosystem (ubiquitous = found every where) and in close association with every type of multi-cellular organism. Microorganisms are EITHER Pathogens: microorganisms that cause disease (3% of all). OR Non-pathogens: microorganisms that do not cause disease.

Why Should We Study Microbiology? Microorganisms living on and inside us are 10 times more than the no. of our cells. These microorganisms are called Normal Flora. Microorganisms are essential for life on this planet as some produce oxygen e.g. algae and cyanobacteria. Many microorganisms are involved in the decomposition of dead organisms and the waste product of living organisms. (Decomposers or Saprophytes). Some microorganisms can decompose industrial waste like oil spills. Microorganisms are part of the food chain as tiny animals feed on them. Others are involved in elemental cycles like carbon, nitrogen, sulfur…

Why Should We Study Microbiology? Many microorganisms are essential in various food and beverage industries e.g. production of cheese. Some microorganisms are used to produce certain enzymes, chemicals, and antibiotics. Microorganisms are essential in the field of genetic engineering . For many years, microbes have been used as “cell models” to study the structure and function of cells in general. Bacteria in intestine help in digestion of food and production of some vitamins. Finally microorganisms can cause disease either by colonizing the body or by production of toxins.

Classification of Microorganism Cellular Acellular Prokaryotes Eukaryotes They are not cells and have no cell membrane. They are composed of few genes protected by a protein coat ex. Viruses. They can live an reproduce only when inside a living cell. Pro  Before Before nucleus , cells without nucleus Eu true or good Cells that have nucleus . Have no nucleus, Have no membrane bond organelles less complex ex. Bacteria and Archaeac Have true nucleus Many membrane bond organelles ex. Algae, protozoa, fungi, plants, animals, and humans.

Virus DNA or RNA segment Protein Coat

Classification of Organisms Based on the is based on similarities and differences in genotypes and phenotypes Microbiologist traditionally emphasize naming of bacterial species into three categories Family (similar to Human clans) Genus (equivalent to human last name) Species (equivalent to human 1st name)

Identification To identify an organism means to learn the organism’s name

Pairs: – diplococci (e.g. N.gonorrheae)

Chains – streptococci, STREPTOCOCCI

Grapelike clusters – staphylococci

Groups of four – tetrads (e.g., Peptococcus)

Palisades (slipping) – organisms tend to place themselves side by side (e.g., Corynebacterium) PALISADES