Download Introduction to Beneficial Bacteria

Name _____________________________________________________________
Introduction to Beneficial Bacteria
Materials
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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?
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b. What are the three basic shapes?
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c. Where have bacteria been located? Name as many places as possible.
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d. How many bacteria live on Earth?
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e. What do bacteria eat?
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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
1
2
13
2
4
14
3
8
15
4
16
16
5
17
6
18
7
19
8
20
9
21
10
22
11
23
12
24
Number of Bacteria
3. Your assignment is to research beneficial bacteria. Using your handouts, answer the
following questions.
a. Name some helpful bacteria. (13-14)
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b. How are bacteria helpful to humans? Give at least four examples. (28)
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c. What do bacteria do that is especially helpful to plants? (4-5; 14)
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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.
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 1030 (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 1023 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 1028 bacteria, and all
aquatic habitats carried 12 x 1028.
But the real jackpot lies underground. More than eight meters below the land surface,
they found between 25 and 250 x 1028 bacteria. And beneath the ocean floor live a
staggering 355 x 1028 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."
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
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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.
Bacteria Deal With Pollution
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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
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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.