Bacteria skinMany of us know bacteria only as “germs,” invisible creatures that can invade our bodies and make us sick. Few know that many bacteria not only coexist with us all the time, but help us do an amazing array of useful things like make vitamins, break down some garbage, and even maintain our atmosphere. Bacteria consist of only a single cell, but dont let their small size and seeming simplicity fool you. Theyre an amazingly complex and fascinating group of creatures. Bacteria have been found that can live in temperatures above the boiling point and in cold that would freeze your blood. They eat everything from sugar and starch to sunlight, sulfur and iron. Theres even a species of bacteria—Deinococcus radiodurans—that can withstand blasts of radiation 1,000 times greater than would kill a human being. contactdental Classification leucothrix Bacteria fall into a category of life called the Prokaryotes (pro-carry-oats). Prokaryotes genetic material, or DNA, is not enclosed in a cellular compartment called the nucleus. Bacteria and archaea are the only prokaryotes. All other life forms are Eukaryotes (you-carry-oats), creatures whose cells have nuclei. (Note: viruses are not considered true cells, so they dont fit into either of these categories.) What Difference Does It Make? Does a bacterium’s cell wall, shape, way of moving, and environment really matter? Yes! The more we know about bacteria, the more we are able to figure out how to make microbes work for us or stop dangerous ones from causing serious harm. And, for those of us who like to ponder more philosophical questions like the origins of the Earth, there may be some clues there as well. How Long They’ve Been Around cyano Like dinosaurs, bacteria left behind fossils. The big difference is that it takes a microscope to see them. And they are older. Bacteria and their microbial cousins the archaea were the earliest forms of life on Earth. And may have played a role in shaping our planet into one that could support the larger life forms we know today by developing photosynthesis. Cyanobacteria fossils date back more than 3 billion years. These photosynthetic bacteria paved the way for todays algae and plants. Cyanobacteria grow in the water, where they produce much of the oxygen that we breathe. Once considered a form of algae, they are also known as blue-green algae. Bacteria are among the earliest forms of life that appeared on Earth billions of years ago. Scientists think that they helped shape and change the young planets environment, eventually creating atmospheric oxygen that enabled other, more complex life forms to develop. Many believe that more complex cells developed as once free-living bacteria took up residence in other cells, eventually becoming the organelles in modern complex cells. The mitochondria (mite-oh-con-dree-uh) that make energy for your body cells is one example of such an organelle. What They Look Like Tags: strep There are thousands of species of bacteria, but all of them are basically one of three different shapes. Some are rod- or stick-shaped and called bacilli (buh-sill-eye). Others are shaped like little balls and called cocci (cox-eye). Others still are helical or spiral in shape, like the Borrelia pictured at the top of this page. Some bacterial cells exist as individuals while others cluster together to form pairs, chains, squares or other groupings. Read more: What They Look Like Comments:0 Notable Bacteria Tags: classic , myfavorite Bacillus anthracis causes anthrax, a deadly disease in cattle and a potential bioweapon against humans .Brucella abortus causes breeding losses in livestock. Cyanobacteria (formerly known as blue-green algae) live in water, where they produce large amounts of the oxygen we breathe. Escherichia coli (a.k.a. E. coli) lives in the gut, where it helps digest food and produces Vitamin K. The bad strain of E. coli O157:H7 causes severe foodborne sickness. Read more: Notable Bacteria Comments:1 What They Eat Tags: borrelia Some bacteria are photosynthetic (foe-toe-sin-theh-tick)—they 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 unusual foods such as iron or sulfur. The microbes that live in your gut absorb nutrients from the digested food youve eaten. Read more: What They Eat Comments:0 How They Move Tags: Some bacteria have hair- or whip-like appendages called flagella used to ‘swim’ around. Others produce thick coats of slime and ‘glide’ about. Some stick out thin, rigid spikes called fimbriae to help hold them to surfaces. Some contain little particles of minerals that orient with the planet’s magnetic fields to help the bacteria figure out whether they’re swimming up or down. Read more: How They Move Comments:0
Posted on: Thu, 27 Nov 2014 13:36:08 +0000
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