Title: Microorganisms and Their Environment
1Microorganisms and Their Environment
2What are Microorganisms?
- A microorganism is any living thing of
microscopic size or smaller. - Bacteria Yeasts Protists
40,000x Mag. 10,000x Mag. 200x
Mag. Also Viruses, some Algae, and some Animals
3The Importanceof Microorganisms
- Microorganisms have positive and negative
effects on humanity. - Many foods, beverages, and medicines are made
with the help of bacteria and yeast. - The spoilage of food and many diseases are
caused by microorganisms.
4The Benefits of Microorganisms
- Beer made with yeast.
- Bread made with yeast.
- Champagne made with yeast.
- Cheese made with bacteria.
- Pickles made with bacteria.
- Sauerkraut made with bacteria.
- Soy Sauce made with bacteria.
- Yogurt made with bacteria.
5The Drawbacksof Microorganisms
- Some bacteria cause infections and diseases like
tuberculosis and bubonic plague. - Some protists cause diseases like malaria and
sleeping sickness. - Some viruses cause diseases like the flu,
measles, chicken pox, polio, and HIV. - Some yeasts also cause infections.
6An Experimental Question
- What conditions are suitable for growing
microorganisms for our benefit? - Or
- What conditions are necessary to prevent the
growth of microorganisms?
7Our Experimental Organism
- Bakers Yeast (S. cerevisiae) is found
naturally growing on grapes and other fruits. - It has been used for thousands of years for
baking and brewing.
8Characteristics of Bakers Yeast
- Readily available in the grocery store.
- Can grow in temperatures ranging from 8 to 40
degrees C. (46 to 104 degrees F.) - Can survive pH levels between 2.4 and 7.4
- Reproduces quickly, optimally doubling every
hour.
9Metabolism of Bakers Yeast
- In the absence of oxygen, yeast will undergo
anaerobic respiration. - C6H12O6 ? 2 C2H6O 2 CO2
- Glucose Ethanol Carbon
- Dioxide
- Yeast can also use sucrose (cane sugar) and
fructose (fruit sugar) as a sugar source.
10Characteristics of Various Liquids
11Independent (Input) Variables
- What conditions should we test in our
experiment? - We will grow our yeast in liquid to easily
deliver the sugar source. - But what liquids should we pick?
12Dependent (Output) Variables
- Remember that we want to determine what
conditions are most suited to growing yeast
cells. - How can we use the reactants and / or the
products of yeast metabolism to answer our
experimental question?
13Yeast Incubation Tube
Grape Juice Time 0 hours
14Sealed YeastIncubation Tube
Apple Juice Time 24 hours
15A Pair of Sealed YeastIncubation Tubes
Apple Juice Milk Time 24 hours
16The CompleteExperimental Set-Up
CO2 Collection Tubes Incubation Tubes
17CO2 Collection Tubes
Time 0 hours 0 ml CO2 Collected
18CO2 Collection Tubes
Time 24 hours 1 ml CO2 Collected
19CO2 Collection Tubes
Time 48 hours 5 ml CO2 Collected