Microbiology

I.

* Dutch amature microscope builder Anton Van Leeuwenhoek was the first to see Microorganisms in detail. The microscope he used to accomplih this was of his own design and involved careful manipulation of the specimen as well as careful focusing.

* Leewenhoek called these tiny organisms "little animalicules" and wrote his findings to the The Royal Society of London which subsequently tested and approved his findings.

* The 19th Century was the beginning of microbiology as we know it. However it was not until the end of this century, that the field was truley accepted. This delay was due to the lack of advancement in the field of microscopy.

* The advancements in this field led to two major questions: 1.Does spontaneous generation occur? 2.What is the nature of contagious disease?

II.

* Spontaneous Generation- The belief that microorganisms sprang from non-living substances.

* The major opponet of this theory was the French chemist Louis Pastuer who eventually disproved spontaneous generation with the following procedure.

I. Proved air was full of dust by filtering the air with gun cotton then dissolving the cotton to leave only filtrate.

II. Created the Pastuer Flask so that no dust could enter to fluid placed in the bottom due to the flask's curved neck.

III. Steralized material in the flask remained clean due to lack of dust.

III.

* Aseptic Technique-The handling of objects so as to maintain sterility.

* Major work done in this area by John Tyndall of England and Fredinand Cohn of Germany.

* They found that endospores form from bacteria and allowed them to survive boiling (the most common sterilization technique of the time.)

IV.

* Germ Theory of Disease- The theory that germs were the cause of disease and the reason for the the contagious factor.

* Showing the relationship between germs and disease gave this field prudence, and a cause to continue its study.

* Major player in this area was Koch, who studied Anthrax and came up with three postulates on contagious disease.

1. The organism should be present in sick organisms, but not in healthy ones.

2. Organism must be cultured in pure culture away from the sick individual.

3. When injected into a healthy organism, the germ should cause the same symptomes as in the sick individual.

4. Organism should be reisolted and recultured and remain the same organism.

* Koch's work helped show that specific organisms have specific effects.

V.

* Pure culture is important according to Koch, because he believed that the color and shape of the colony showed each individual colony.

* Koch inferred that each colony sprang from an individual bacterium because movement was not possible on the solid surface.

* Koch's work led to the successful trearment of many diseases.

I. Cellular Organelles

A. Mitochondria

* The major energy producing component of the cell, they are small, membrane bound, granuler, and contain enzymes.

* Electron microscopy allowed the mitchondria to be viewed close-up which revieled that thier shape can range from spherical to rod-shaped.

* Each mitchondrian has an inner matrix and an outer envelope.

* The outer envelope consists of an inner and outer electron-dense membranous component, the inner portion is covered with cristae, or projections inward toward the matrix.

* The matrix of the mitchondria is an amorphorus (finely granular) substance which contains DNA, RNA, and possibly ribosomes.

B. Lysosomes

* Lysosomes are membrane-bound organelles primarily responsible for inter-cellular digestion.

* There are two types of lysosomes, primary (those which have not yet began enzymatic processes) and secondary (those which have.)

* Phagosomes: Pinocytic and Phagocytic invaginations which have engulfed liquid/solids and broken off of the cell membrane.

* Phagcytosis: The engulfing of solids by the creation of phagosomes.

* Pinocytosis: The engulfing of liquids by creation of phagosomes.

* Secondary lysosomes are a group of varied structures such as multi-vascular bodies, residual bodies, autosomes, hemosiderin granules, and lipofuscin granules. All these arise through the fusion of a primary lysosome and a vacuole.

C. Centrioles

* Short fiberous rod-shaped organelles.

* Within the the cell, there are usually two centrioles collectivelt referred to as Diplosome.

* Located near the nucleas, each is made of 9 sets of 3 microtubules.

* Centrioles serve to organize micotubles and to determine polarity during late prophase and metaphase of cell division.

* These organelles can also move to a location below the cell membrane where they give rise to basal bodies, cilia, and flagellae.

D. Microtubules (the cytoskeleton)

* Microtubules are straight or slightly curved delicate organelles located in almost all cells.

* Microtubules serve several functions, they maintain cell shape as well as aiding in interacellular transport.

* In cellular division, they aid in pulling the chromosomes to different poles of the cell.

* It is also thought that microtubules could be responsible for transporting water within the cell.

E. Filaments

* Filaments are responsible for three major functions:

A: Cytoskeleton filaments- Provide rigidity as well as tensile strength for the cell.

B: Myofiliments-

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