BACTERIA AND ANTIBIOTICS
LAB REPORT

Bryan Bennett
Ms. Johnson
Biology 09 period 8
March 12, 2013

Introduction:

1. Eubacteria
-Has cell wall with peptidoglycan
-They can live nearly anywhere on earth (sky to underground)
-Unicellular
-Prokaryotic
-Reproduce Asexually

Archaebacteria

-Cell wall without peptidoglycan
-Live in environments without oxygen (anaerobic)
-Prokaryotic
-Unicellular
-Reproduce Asexually
-Oldest bacterial form
-Unique lipids in their cell membrane
-DNA sequence is more like other Eukaryotes than other bacterial types (eubacteria)

2. Bacteria are classified into four groups: * PHOTOAUTOTROPHS * PHOTOHETEROTROPHS * CHEMOAUTOTROPHS * CHEMOHETEROTROPHS

3.

4. Many bacteria are heterotrophic which is to thrive off other organisms. The type of bacteria that causes disease are heterotrophic parasites. There are also many harmless bacterial parasites, many of which can be helpful to their hosts. Autotrophic bacteria manufacture their own food by chemosynthesis and photosynthesis. In aerobic respiration a series of reactions convert glucose to carbon dioxide and water and give off energy. Free oxygen is required as the final acceptor for electrons and hydrogen to form water. Bacteria, able to grow in the presence of oxygen, are called aerobic bacteria. Pseudomonas is an example of aerobic bacteria. In anaerobic respiration free oxygen isn’t required. Organic compounds are the final electron acceptors in anaerobic respiration. The bacteria able to grow in the absence of oxygen are called anaerobic bacteria. Some bacteria are neither aerobic nor anaerobic, but facultative E.coli is an example facultative anaerobic bacteria. Facultative bacteria grow either in the presence or absence of oxygen. All prokaryotic bacteria reproduce asexually. Bacterial reproduction most commonly occurs by a kind of cell division called binary. Binary fission results in the formation of two bacterial cells that are genetically identical. During binary fission, the single DNA molecule replicates and both copies attach to the cell membrane. Then, the cell membrane extends between the two DNA molecules. Once the bacterium just about doubles its original size, the cell membrane begins to pinch inward. A cell wall then forms between the two DNA molecules dividing the original cell into two identical “daughter” cells.
5. Antibiotics are drugs/medications used to treat infections caused by bacteria. Bacteria are microscopic organisms, some of which can cause illnesses. Some bacteria are harmless, while others can be good for us. Before bacteria can multiply and cause symptoms, the body's immune system can usually destroy them. We have special white blood cells that attack harmful bacteria. Even if symptoms do occur, our immune system can usually cope and fight off the infection. There are occasions, however, when it is all too much and some help is needed from antibiotics.
Although there are a number of different types of antibiotics they all work in two different ways. A bactericidal antibiotic kills the bacteria. A bactericidal usually either interferes with the formation of the bacterium's cell wall or its cell contents. A bacteriostatic cuts off the possibility of the bacteria multiplying.
6. Human immune systems have a number of ways to fight infections or to prevent them. The human body’s immune system doesn’t just include white blood cells, which attempt to catch and destroy germs, but a variety of mechanisms that stop germs from creating infection. In most cases, humans have certain properties in their bodies that are called innate immunities, allowing bodies to fight infections at virtually all times. For example, the skin, our largest organ, is constantly fighting infections, or warding off infection by acting as a barrier against foreign, non-human cells. Other parts of our bodies, or contents in our bodies are always on guard to fight infections. The gut and stomach contain mucus that can trap small numbers of foreign bacterial cells, keeping the body from becoming infected. Human bodies use a variety of acids in organs that create hostile environments for foreign cells. We also host helpful bacteria in our bodies that help keep other bacteria entering the body in check.
7. Genetic engineering is the process of manually adding new DNA to an organism. The goal is to add one or more new traits that are not already found in that organism. Examples of genetically engineered (transgenic) organisms currently on the market include plants with resistance to some insects, plants that can tolerate herbicides, and crops with modified oil content. Bacteria plays an important role in genetic engineering. As we already know that bacteria genome is easy to manipulate and they can be mutated easily. Moreover their frequency of multiplication is very high. So we can mutate a bacterium and then transfer it to the host.
8. The most dirty place in the school would most likely be the boy’s bathroom outside the lunchroom, specifically the faucet handles. Due to all the germs from lunch and other places, the faucets are a great place for bountiful bacteria to prosper. As hundreds of kids grab the handles before their hands are cleaned, bacteria gets wiped onto the metal surface and begins to multiply.
Problem: Will the three diverse types of antibiotics slow the growth of the E.coli compared to the control?
Hypothesis: The three types of antibiotics will have different results in reaction to the bacteria as they are diverse and will act differently in separate ways to kill the E.coli. Most likely all will do something to kill it, however some antibiotics may be more successful than others.

Procedures:
Materials: E.coli, swabs, test tubes, burner, petri dish, tweezers, alcohol, antibiotic tablets (3), para film, ruler, tin foil, pens.
Steps:
Inculcating the Dish:
1. Uncap the E.Coli with your pinky.
2. Unwrap the swab and put it into the tube to get some E. Coli on the swab.
3. Then run the top of the tube over the flame and screw the lid back on
4. Open the dish military style and skate the E. Coli over each of the four quadrants.
Application of Antibiotics:
5. Get tweezers and dip them in the alcohol, then put them into the flame to sterilize them
6. Put a different kind of antibiotic tablet in each quadrant (expect the control) be sure to place it in the center of the section.
7. Stretch the para film over the out side of the disk to seal it.
Afterwards:
8. Remove the para film
9. Locate where the bacteria has grown
10. Measure from the antibiotic tablets to the closest bacteria colony to determine which tablet worked the best.
--To validate my research, I would use other antibiotics to do this experiment and repeat these steps, comparing the new results to the previous ones.

Data: Group # | Tetracycline | Ecythomycine | Streptomycin | 1 | 6.6 mm | 3.3 mm | 5 mm | 2 | 8.5 mm | 0 mm | 12.5 mm | 3 | 12.5 mm | 6 mm | 19 mm | 4 | 0 mm | 15.3 mm | 5.5 mm | 5 | 0 mm | 20 mm | 5 mm | 6 | 7 mm | 1 mm | 4.2 mm | Averages (Divide by 6): | 5.7 mm | 6.6 mm | 8.5 mm |

Control (Ecoli)
Control (Ecoli)

Ecythomycine
Ecythomycine
Movement totals:

Ecythomycine- 6.6mm

Streptomycin- 8.5mm

Tetracycline- 5.7mm
Movement totals:

Ecythomycine- 6.6mm

Streptomycin- 8.5mm

Tetracycline- 5.7mm

Streptomycin
Streptomycin
Tetracycline
Tetracycline

Individual Experiment totals:
1. Boys (Dirty, Lunch room) bathroom
2. Girls (Dirty, locker room) bathroom
3. Control
4. Boys basement bathroom (cleaner)
5. Girls Basement bathroom (cleaner)
6. Control Individual Experiment totals:
1. Boys (Dirty, Lunch room) bathroom
2. Girls (Dirty, locker room) bathroom
3. Control
4. Boys basement bathroom (cleaner)
5. Girls Basement bathroom (cleaner)
6. Control

Class Averages
Class Averages
Length traveled (mm)
Length traveled (mm)

The largest average in movement was in Streptomycin, which moved 8.5mm from its original place. This means that Streptomycin was the most powerful antibiotic used in this lab, so the bacteria must have lied on it.

Analysis/ Interpretations:
The zone of inhibition represents the average length the bacteria moved in the lab. It could be anywhere between zero and twenty in my group’s lab. The more the bacteria moved, the more powerful the antibiotic is. Therefore, Streptomycin is the most powerful antibiotic used. The best antibiotic used was Streptomycin, and the least powerful was Tetracycline. Tetracycline’s results differed from those in the other groups, because the average was the smallest. Every antibiotic tablet is different from another, so you will usually get unlike results each time. Streptomycin was the most powerful, because the bacteria lied on top of the antibiotic. The antibiotic of Tetracycline was the hardest to control because it had already developed a near resistance to the E.coli. An antiseptic is a compound that is used to slow down the reaction of bacteria spreading. Antiseptics destroy microbes, and can protect a wound from further contamination.

Conclusion:
In this experiment, Streptomycin was proved to be the most powerful antibiotic on E.coli. Tetracycline moved 5.7mm on average, Ecythomycine moved 6.6mm on average, and Streptomycin moved 8.5mm on average, which was more then the others. All of these antibiotics worked against the bacteria, however Streptomycin was the most effective proving its capabilities in fighting bacteria. If one were to be applied in this specific case of infection, Streptomycin should be applied as shown to be most effective.

Citations: 1. Mac, Ryan. "What Is Bacterial Respiration?" LIVESTRONG.COM. Livestrong, 12 Aug. 2011. Web. 12 Mar. 2013.

2. Nordqvist, Christian. "What Are Antibiotics? How Do Antibiotics Work?" Medical News Today. MediLexicon International, 20 Apr. 2009. Web. 12 Mar. 2013.