culled from : Microbe world(edu.pe.ca/) To learn more follow this link to join ; https://facebook/groups/578259865597635/ Classification of Microbes The term microbe is short for microorganism, which means small organism. To help people understand the different types of microbes, they are grouped or classified in various ways. Microbes are very diverse and represent all the great kingdoms of life. In fact, in terms of numbers, most of the diversity of life on Earth is represented by microbes. and They are 1. Virus A virus is too small to be seen without a microscope. A virus is basically a tiny bundle of genetic material carried in a shell called the viral coat. Some viruses have an additional layer around this coat called an envelope. Thats basically all there is to viruses. There are thousands of different viruses that come in many shapes. Many are multi-sided or polyhedral. If youve ever looked closely at a cut gem, like the diamond in an engagement ring, youve seen an example of a polyhedral shape. Unlike the diamond in a ring, however, a virus does not taper to a point, but is shaped the same all around. Other viruses are shaped like spiky ovals or bricks with rounded corners. Some are like skinny sticks while others look like pieces of looped string. Some are more complex and shaped like little spaceship landing pods. Viruses are found on or in just about every material and environment on Earth from soil to water to air. Theyre basically found anywhere there are cells to infect. Viruses can infect every living thing. However, viruses tend to be somewhat picky about what type of cells they infect. Plant viruses are not equipped to infect animal cells, for example, though a certain plant virus could infect a number of related plants. Sometimes, a virus may infect one animal and do no harm, but cause a great deal of damage when it gets into a different but closely related animal. Viruses exist to reproduce only. To do that, they have to take over suitable host cells. Upon landing on a suitable host cell, a virus gets its genes inside the cell either by tricking the host cell to pull it inside, or by connecting its viral coat with the host cell wall or membrane and releasing its genes inside, or by injecting their genes into the host cells DNA. The viral genes are then copied many times, using the process the host cell would normally use to reproduce its own DNA. The new viral genes then come together and assemble into whole new viruses. The new viruses are either released from the host cell without destroying the cell or eventually build up to a large enough number that they burst the host cell. 2. Bacteria Bacteria consist of only one cell, but theyre a very complex group of living things. Some bacteria can live in temperatures above the boiling point and in cold below the freezing point. There are thousands of species of bacteria, but all of them are basically one of three different shapes. Some are rod- or stick-shaped; others are shaped like little balls. Others still are helical or spiral in shape. Some bacteria cells exist as individuals while others cluster together to form pairs, chains, squares or other groupings. Some bacteria can make their own food from sunlight, just like plants. Also like plants, they give off oxygen. Other bacteria absorb food from the material they live on or in. Some of these bacteria can live off iron or sulfur! The bacteria that live in your stomach absorb nutrients from the digested food youve eaten. Some bacteria move about their environment by means of long, whip-like structures called flagella. They rotate their flagella like tiny outboard motors to propel themselves through liquid environments. They may also reverse the direction in which their flagella rotate so that they tumble about in one place. Other bacteria secrete a slime layer and ooze over surfaces like slugs. Others stay almost in the same spot. Bacteria live on or in just about every material and environment on Earth from soil to water to air, and from your body to the Arctic ice to the Sahara deserts. Each square centimeter of your skin averages about 100,000 bacteria. A single teaspoon of soil contains more than a billion (1,000,000,000) bacteria. 3.Algae Algae are found in fresh and salt water around the world. They can also grow on rocks and trees and in soil when enough water is available. Most algae are able to make energy from sunlight, like plants do. They produce a large amount of the oxygen we breathe. However, at some stages of their lives, some algae get their nutrients from other living things. Diatoms are one kind of algae. They have hard shells made out of glass. When they die, these shells sink to the bottom of their watery environments. We mine deposits of these glass shells that formed hundreds of thousands of years ago to make abrasives, shiny road paint and grit in toothpaste. Diatoms come in all sorts of shapes—some are round and others are oval. Some look like leaves and others like fat commas. 4, Fungi Fungi are organisms that scientists once confused with plants. However, scientists have found that, at the cell level, the fungi are more like animals than they are like plants. For one thing, fungi cannot synthesize their own food like plants do, but instead they eat other organisms as do animals. Fungi come in a variety of shapes and sizes and different types. They can range from single cells to enormous chains of cells that can stretch for miles. Fungi include single-celled living things that exist individually, such as yeast, and multicellular clusters, such as molds or mushrooms. Yeast cells look round or oval under a microscope. Theyre too small to see as individuals, but you can see large clusters of them as a white powdery coating on fruits and leaves. 5. Protozoa The word protozoa means little animal. They are so named because many species behave like tiny animals, they hunt other microbes as food. Protozoa mainly feed on bacteria, but they also eat other protozoa,and sometimes fungi. Some protozoa absorb food through their cell tissues. Others,surround food and engulf it. Others have openings called mouth pores into which they sweep food. All protozoa digest their food in stomach-like compartments. As they digest, they make and give off nitrogen, which is an element that plants and other higher creatures can use. Protozoa vary in size from 1/5,000 to 1/50 of an inch in diameter. They can be classified into three general groups based on their shape. One group is the Ciliates, which are generally the largest protozoa. They have hair-like projections called cilia and they eat the other two types of protozoa as well as bacteria. The second group is the Amoebae. The third group is the Flagellates, which are usually the smallest of the protozoa and have one or several long, whip-like projections called flagella extending from their cells. To hunt, protozoa have to be able to move about. Amoebas ooze about by extending parts of their cells. Amoebae have fluid cell membranes or coverings that they can stretch out, bend and curve. As the membrane moves outward, the fluid and other parts inside the cell follow, flowing into the new bulge created by the moving membrane. Many Ciliates swim along by beating their cilia in a rhythmic pattern, like so many tiny oars. Flagellates swim by waving their flagella, using them much like a fish uses its tail to push itself through water. Most protozoa do us no harm. But there are a few that cause diseases. One type of amoeba can live in human intestines. It feeds on red blood cells and causes a disease known as dysentery. Another species of protozoa can sicken hundreds of thousands of people when it gets into the tap water. Perhaps the best-known deadly protozoa causes malaria, a terrible disease that leads to about 800,000 deaths each year worldwide.
Posted on: Wed, 05 Nov 2014 20:21:50 +0000
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