Academic matters...my first report..eubacteria

Introduction
A. BACTERIA
Bacteria are a group of single-celled microorganisms that, along with the Archae, are classified as prokaryotes. Prokaryotic cells are structurally much simpler than eukaryotic cells because they have no internal membrane-bound organelles. Most prokaryotic cells are also much smaller than eukaryotic cells. A typical bacterial cell is about 1 micrometer (1 um) in diameter, while eukaryotic cells range from 10 to 100 um in diameter.
Although bacteria do not possess organelles, the complex and diverse functions carried out by organelles are present in other parts of the bacterial cell such as the cell membrane. Moreover, while bacteria may seem "simple" at first glance, their lack of structural complexity actually represents a clever and amazingly successful adaptation for survival. The lack of complex internal structures allows bacterial cells to devote all of their cellular energy to rapid growth whereas eukaryotic cells devote much of their energy to maintaining cellular complexity.
Bacteria and other prokaryotes are found in every environment on the planet, including all of the habitats where eukaryotes live, but also in environments considered too extreme or inhospitable for eukaryotic cells/organisms - such as boiling water or ice. Thus, the outer limits of life on Earth are usually defined by the existence of prokaryotes. Although many people associate bacteria with illness, less than 1% of all known bacterial species are capable of inducing disease.
The vast majority of bacterial species are free-living (non-disease causing) and many bacteria form symbiotic relationships with plants and animals that usually benefit both organisms. Thus, the lives of plants and animals are dependent upon the activities of bacterial cells. For plants, bacteria help maintain the pH of the soil and provide important nutrients. In animals, including humans, skin and mucous membranes are habitats for a variety of bacterial species. The human body provides multiple habitats for 200-500 different species of bacteria and the total number of bacteria exceeds the number of cells in all the tissues and organs which comprise a human. In this lab, we will be sampling multiple environments for different species of bacteria.

B. CULTURING BACTERIA ON AGAR PLATES
Individual bacteria are too small to be seen without the aid of a microscope and, before the work of Robert Koch (1843-1910), were impossible to isolate as pure cultures. Koch was studying the transmission of bacteria-borne diseases and, like his colleagues at the time, was frustrated because he could never grow a pure culture of any bacterial type. Any attempt to isolate and grow up one type of bacteria always resulted in a mixture of bacterial cell types, as visualized by observing differences in the appearance and size of the cells by light microscopy. One day, Koch boiled a potato, cut it in half, and accidentally left the potato out on his kitchen counter overnight. In the morning, he was amazed to see small "colonies" of different colors and shapes (morphologies) and immediately realized that bacteria from the air had landed on the sterile potato surface during the night and had begun to divide.
Each colony represented a clonal population derived from a single cell that had landed on the potato's surface, and Koch was delighted to see that when he placed a colony in some sterile media and then viewed it under the light microscope, all the bacterial cells had the same appearance.
Koch's discovery of how to grow up pure cultures of different bacteria eventually led to the development of the ideal medium for promoting such growth: agar. Agar is an unbranched polysaccharide obtained from the cell membranes of some species of red algae or seaweed, and it cannot be digested (liquified) by bacteria. Therefore, it provides an ideal surface for bacterial cell growth (cell division). Bacterial cell division rates are very fast in comparison to eukaryotic organisms. Many bacterial species can undergo cell division every 20 minutes. Thus, in 8 hours, a single bacterial cell can give rise to a population of millions of cells, which cluster together as a colony visible to the naked eye. An average colony may be composed of between 300,000-5,000,000 identical cells. Colonies of different species will have different observable or phenotypic characteristics, including size, shape, height, texture, and color. These are collective known as the colony morphology of the species and can be used to distinguish between different species grown on an agar plate. The different colony morphologies (phenotypes) are the result of the different genetic makeup of each individual species.

Objectives
I. To demonstrate pure culture technique with Petri dish.
II. Explain why bacterial species can be found in every environment.
III. Explain the purpose of agar and colony formation in isolating and studying bacteria.

Material
Table 1: Table of material
Material
1. Inoculating loop
2. Burner Bunsen
3. Pen
4. Petri dish
5. Nutrient agar
6. Distilled water
7. Swab cotton
8. Ethanol
9. Microscope
10. Gloves
11. Mouth mask
12. Stirring rods
13. Beaker
14. Cheek cells
15. Dilute yogurt
16. Air

Method
a) Agar preparation
1. The laboratory table were swipe with clean tissue contain ethanol to avoid unneeded bacteria.
2. About 300ml of water is boiled in a beaker using a bunsen burner. Then, put the nutrient agar in that beaker and stirred until they are mixed.
3. The nutrient agar was pour into the Petri dish that has been sterile with the hot water.
4. When pouring, the lid of the Petri dish is opened slightly to avoid from other microbes.
5. The nutrient agar is poured until three-quarters of the Petri dish.The surface of the agar was flamed slightly to avoid from bubbles.

b) Streaking of agar
1. The inoculating loop was placed in the Bunsen burner flame until the loop is red hot.
2. The loop allowed to cool and dip it into a sample of dilute yogurt.
3. The lid of sterile agar plate was lift slightly with the other hand and lightly spread the content of the inoculating loop over the surface agar.
4. The lid of plate was close and the loop returned to the Bunsen burner until red hot.
5. The base of the plate was label with an indelible marker.
6. The procedure 1 till 5 was repeat with the second plate using air.
7. The third plate was prepared for cheek cells. The cheek cells got from one of the group members by swipe the cotton swab in her mouth at cheek region. Then, procedure 1-5 repeated again.
8. The last plate act as a control. Therefore it only contain agar. Procedure 1 to 5 were NOT repeat for this plate.
9. All of the plate then kept in the laboratory for three days and the differences occur in all plate were taken everyday.

c) Collecting Data
1. After three days, every agar plates were cut to take the bacteria sample.
2. The slide has been made for each plate for observation under the microscope.
3. The bacteria found was recorded and it shape was draw to differentiate between each bacteria.