Microbiology

March 19th, 2012 =Taxonomy= A species is a group of organisms that are capable of breeding with each other and producing viable offspring.

Scientists classify micro-organisms in order to know what characteristics we can expect them to have. It makes it easier to study them.

Organisms are classified by general shared characteristics and then using more specific characteristics.

reproduction || + Activity 2.2 Using a Classification Key
 * || Monera || Protists || Fungi ||
 * Cells || one cell || one cell || at least one cell ||
 * Nucleus || no nucleus || nucleus || nucleus ||
 * Reproduction || asexual reproduction || asexual reproduction || asexual and sexual
 * Examples || bacteria and blue-green algae || Amoeba and Euglena || Mould, Yeast ||

March 20th 2012

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 * Bacteria**



Monera (bacteria) are responsible for:
 * **diseases:** pneumonia, strep throat, staph infections, botulism (food poisoning), syphilis, cholera, anthrax, leprosy and the bubonic plague
 * **ecosystem functions**: nitrogen fixation, decomposers, and producers (blue-green algae)
 * **food production**: wine, cheese, yogurt, vinegar, bread, pickles, sauerkraut, kimchi

Viruses are different from living organisms in that they are not made of cells. They are simply genetic material (DNA or RNA) in a protein coat.

Bacteria feed by releasing chemicals to break down food sources into particles small enough to enter the cell. This process is called decomposition or digestion.

Bacteria are different from each other in that different species have different shapes and associations (colonies). All bacteria have a cell wall and do not have a nucleus.

Algae are different from bacteria in that they can make their own food by photosynthesis and can only survive in water.

Binary fission is a mode of reproduction in which a cell divides into two equal halves.



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Wednesday, March 21st
 * Protists**

Introduction to Protists media type="youtube" key="-zsdYOgTbOk" width="560" height="315"



Types of protists media type="youtube" key="Ln69k7LyTsU" width="420" height="315" The name protist means 'first life'. They are eukaryotic single-celled organisms. That is to say, they have a nucleus and membrane-bound organelles. All protists are aquatic and live in water.

Protists can be divided into two groups: protozoa (first animals) and algae.

Protist algae, all colours except blue-green, differ from the bacterial blue-green algae in that they have nuclei and chloroplasts. They have cell walls made of cellulose. Similar to blue-green algae, they are producers.

Protozoa do not have cell walls and do not obtain their energy from photosynthesis. Instead, they obtain their energy by being predators, decomposers or parasites. Parasites are organisms that live on or inside other organisms. Some examples of protozoa include amoeba, paramecia and plasmodia. Amoeba reproduce through mitosis while plasmodia undergo sexual reproduction which involves both humans and mosquitos.

Watch some videos of amoeba and paramecium feeding.

Amoeba feeding. media type="youtube" key="W6rnhiMxtKU" height="315" width="420" media type="youtube" key="IONePT2ixZQ" height="315" width="420"

Paramecium feeding. media type="youtube" key="l9ymaSzcsdY" height="315" width="420" media type="youtube" key="a4aZE5FQ284" height="315" width="560"

Research one of the diseases caused by protists: African sleeping sickness, malaria, Chagas' disease, toxoplasmosis, leishmaniasis, giardiasis

Thursday, March 22nd

Fungi are a group of organisms that include mushrooms, yeasts and moulds. They are involved with the making of foods like cheese, yogurt, beer and bread but can also cause disease like athlete's foot, make medicines like penicillin, and are decomposers.
 * Fungi**

Fungi have nuclei and cell walls. They cannot produce their own food and are either parasites or decomposers. Their cells are usually either round to oval single cells or long, and thread-like (filamentous). Sometimes cells are considered multi-nucleated since the cytoplasm of adjacent cells are incompletely separated. The thread-like cells are known as mycelium.

The round or oval fungi are usually **yeasts**. The filamentous fungi are usually **moulds**.

Different examples of fungi include moulds (bread and penicillium), yeasts and mushrooms.

Fungi reproduce both sexually and asexually. Asexual reproduction occurs through fragmentation, spore production and budding.**Budding** is the division of a cell to form 2 new cells but the new cell is smaller than the parent cell. **Fragmentation** occurs when a part of the organism breaks off and forms a new organism. **Spores** are special structures similar to seeds which allow mould to spread to a new area.



Growing mushrooms

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Many viruses cause disease. They are not made up of cells. They are very small and are only genetic material (DNA or RNA) wrapped up in protein. Viruses cannot survive unless they are inside another living organism. This makes them all parasites.
 * Viruses**



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