Introduction to Beneficial Bacteria

Transcription

1 Name Introduction to Beneficial Bacteria Materials 11X17 paper Colored Pencils Markers Magazine Scissors Glue Procedure 1. Using your What is a Microbe? booklet and other handouts, answer the following questions. (11-14) a. What do bacteria look like? b. What are the three basic shapes? c. Where have bacteria been located? Name as many places as possible.

2 d. How many bacteria live on Earth? e. What do bacteria eat? 2. How quickly do bacteria reproduce? How many can you get over a short period? You have been given a bacterium. As you observe it, you notice it divides every hour. Assuming no bacteria die during the 24-hour period, how many bacteria will exist after the 24-hour period? Bacterium Division Chart Hour Number of Bacteria Hour Number of Bacteria

3 3. Your assignment is to research beneficial bacteria. Using your handouts, answer the following questions. a. Name some helpful bacteria. (13-14) b. How are bacteria helpful to humans? Give at least four examples. (28) c. What do bacteria do that is especially helpful to plants? (4-5; 14) Collage 4. Using the information you have, your assignment is to make a collage (a form of art in which various materials such as photographs and pieces of paper or fabric are arranged and stuck to a backing) showing beneficial uses of microorganisms.

4 Counting Bacteria by David Tenenbaum How many bacteria share the planet with us? According to William Whitman, a microbiologist at University of Georgia, the number is 5 x (5 followed by 30 zeroes). This is a big number by any standard. If you had that many pennies, they would make a stack a trillion light years long. Just where are all these bacteria? Some bacteria live in the human gut -- a total of 3.9 x among all six billion of us. (Remember that most intestinal bacteria are helpful.) Most bacteria live under ground or on the sea floor. 92% to 94% of all bacteria live underground. They are found hiding in the cracks and pores of rock and sediment, lacking sunlight, fresh air, even cable TV. A Whale of a Census Unable to count bacteria individually, Whitman and colleagues opted for a sampling technique. They divvied the world into forests, deserts, freshwaters, and shallow and deep ocean waters. Then they studied the science literature looking for studies on the concentration of bacteria in each habitat. From there it was simple multiplication -- size of habitat in milliliters times number of bacteria per milliliter equals total number of bacteria in that habitat. The math showed that the top eight meters of soil carry 26 x bacteria, and all aquatic habitats carried 12 x But the real jackpot lies underground. More than eight meters below the land surface, they found between 25 and 250 x bacteria. And beneath the ocean floor live a staggering 355 x bacteria. World's Least Useful Number? May we predict your response? The results are a) "astonishing or b) "a waste of time; the total number of bacteria is as useless as it is incomprehensible."

5 The research demonstrates that all discussions of life, and its effects on Earth, had best take into account the hidden habitat. Bacteria, after all, make some of the oxygen and almost all of the nitrogen in our air. Bacteria also store carbon. That has bearing on the study of global warming. Removing carbon from the air slows the rise of carbon dioxide that is causing global warming. Their Infinite Variety The data also help explain the variety of bacteria. It is this variety which allows them to live everywhere, from ice to boiling water, from deep in the Earth to high in the atmosphere. Bacteria come in varieties that can cause human and crop diseases, or supply medicines and new molecules for industry. How Do Bacteria Eat? "Eat" is really a figure of speech when it comes to bacteria. They don't have mouths or digestive systems, so they can't eat in the same way that animals do. Rather, they absorb molecules directly into their cells via channels in their cell walls and membranes. They then break the molecules down and convert them into the materials they need. When bacteria encounter molecules that are bound together -- such as human tissues -- the bacteria secrete enzymes that break the tissues down into small parts. What Do Bacteria Eat? Species of bacteria exist that eat almost anything on Earth. Not only organic substances, such as sugars, proteins, soybean oil and wood, but even inorganic -- sulfur, iron and gasoline. Termites and other "wood eating" creatures have bacteria in their stomachs that actually eat and break down the wood. One of the main ways bacteria are classified is according to what they eat. Benefits of Bacteria Bacteria are the only living things which can fix nitrogen (change nitrogen so plants can use it). They are therefore essential to all other life on Earth. Bacteria are the major decomposers of dead plants and animals. Cows and other animals keep bacteria in their stomachs, as only bacteria can break down the tough cell walls of plants. People use bacteria to turn wine into vinegar and milk into cheese and yogurt.

6 Bacteria Deal With Pollution Break down cancer causing chemicals to non-cancer causing materials. Digest pesticides. Remove chemicals from drinking water. Clean up oil spills. Bacteria That Recycle Nutrients Bacteria that live in soil all over the world recycle the nitrogen and carbon in plants and animals after they have died. Soil bacteria are key to the processes of decomposition. Foods Made Using Bacteria Artificial Sweeteners- Bacteria make some ingredients used in artificial sweeteners. Brie, Camembert, and other soft cheeses - a fungus breaks down the acids in the curd. Bacteria are also involved in keeping the cheese soft. Butter - A starter containing bacteria gives butter its taste and smell. Buttermilk - Formed by adding unpasteurized milk containing bacteria to undergo fermentation at room temperature. Cheese - Different types of bacteria and fungi are added to milk curd and are allowed to ferment and age. The cheeses made have different tastes and hardnesses. Carbon dioxide produce by bacteria is responsible for the holes in Swiss cheese. Chocolate - Pods containing the cocoa beans in the pulp are collected, broken open, and the beans are removed. The beans are spread on banana leaves or put in sweat boxes where wild yeast ferment them for 2-9 days, producing various flavors. Corn Syrup Bacteria and fungi help thicken the corn syrup. Ketchup - Contains vinegar made by from bacteria. Monosodium Glutamate (MSG) - The flavor enhancer, MSG, used in Asian cooking is produced by bacteria. Olives - Bacteria is used to remove sugars from the plants and add flavor and aroma. Pickles Bacteria is used to remove sugars from the plants and add flavor and aroma. Salad Dressing - Is made with vinegar which is made from bacteria. Sauerkraut Cabbage is fermented in bacteria to give sauerkraut its flavor. Soy Sauce Bacteria and fungi are used when making soy sauce. Vinegar - A product made by dripping ethanol over wood chips covered with bacteria. Yogurt Bacteria change milk products into yogurt.