Human Biology Experiment

The purpose of this Human Biology experiment was to explore the environmental growth throughout the campus of Mount Wachusett Community College. Bacteria were first observed by Antonie van Leeuwenhoek in 1676, using a single-lens microscope of his own design. He called them “animalcules” and published his observation in a series of letters to Royal Society. The name bacterium was introduced much later, by Christian Gottfried Ehrenberg in 1838. (

I took swabs from different areas with Mount Wachusett Community College. With these swabs I will find out what kinds of bacterial growth grew within the college environment, if any. Once the bacterial organisms have grown, I will test certain cleaners to find out which will eliminate the bacterial growth.
Bacteria are single celled organisms that can only be seen with a microscope. They are so small that scientists measure them in micrometers. A micrometer is equal to one millionth of a meter. On average, a bacterium is equal to one micrometer long. This would mean that the head of a pin could hold hundreds of thousands of these microorganisms.

Materials and Methods
Throughout this microbiology experiment I used several materials and methods that will be listed below.

The following materials discussed above were used during this experiment. During lab 1 I used a pen and paper to record information during the experiment process. I used four sterile swabs to swab different environments throughout Mount Wachusett Community College. One agar plate was divided into four even sections and used to plant the bacteria from the swabs. One crayon was used for labeling the agar plate.

During lab 2 I used many materials. They were the following; a ruler was used to measure the growth of the bacteria that had grown in the agar plate. Bacteriological loops were used to transfer the colonies from the agar plate to a clean slide. Once transferred a Bunsen burner was used to fix the smear to the slide. The next several materials used were for the gram staining process, crystal violet, tap water, gram’s iodine, ethyl alcohol, safranin and bibulous paper. A microscope was used to view the slides and oil was applied to the slide to view them at oil immersion (about 100x). The following cleaners were used on a small filter paper disk, Povidone iodine, Bactine, Dawn dish soap, and Mr.

Clean multi- surface.
During lab three there was no additional materials used.

I took 4 sterile swabs and swabbed the following 4 environments within Mount Wachusett Community College: Desk top in room 340, Stairway railing third floor, men’s bathroom door on third floor and the recycling trash bin on the third floor. Next, I planted the bacteria from the swabs into an agar plate. After several days the agar plates had bacterial growth. The bacterial growth was then transferred from the agar plate to a clean slide.

The colonies that were transferred and smeared onto a clean slide, then fixed to slide by using a Bunsen burner. Now they are ready for the gram staining procedure. This procedure is: 1) Flood the smears with crystal violet for one minute. 2) Rinse slides thoroughly with tap water.3) Flood smears with gram’s iodine for one minute. 4) Rinse slide thoroughly with tap water. 5) Decolorize with ethyl alcohol. 6) Rinse immediately with tap water. 7) Flood smears with safranin for two minutes. 8) Rinse slides thoroughly with tap water. 9) Blot dry with bibulous paper.

The next method used was the disk method. I divided an agar plate into four sections with a wax crayon. Then I “seeded” that plate with the largest bacteria colony that grew. Using sterile technique, I took a loopful of bacteria and spread it over the entire plate. Finally I placed filter paper disks each saturated with a different cleaner into each one of the four sections.(lab day 2)

I am going to start with the results from sample 1. This sample was taken from the desk top in room 340. The macroscopic view showed several colonies growing. When the largest colony was measured with a ruler it read .04cm. This colony appeared to be white or orange in color and to have smooth raised circle structure. Once viewed microscopically I learned that this colony was gram negative cocci in clusters. They appeared as pink circles in clusters.( )

Sample 2 was taken from the stairway railings on the third floor. Macroscopically I saw many colonies growing some were yellow in color their surfaces looked bumpy and raised. Others looked to be light red in color with a smooth raised circular look to them. The largest colony measured .06cm and the smallest measured .03cm. Once viewed microscopically I found that these colonies were gram positive cocci in cluster, they appeared to be blue circles in clusters. (

Next is sample 3 which was taken from the men’s bathroom door on the third floor. When view macroscopically there was only a few colonies growing they were either white or yellow in color. The largest colony measured .05cm and appeared to be smooth and rose in a circular shape. The smallest colony was less then .01cm and was slightly raised with a smooth texture and circular shape. When viewed microscopically I saw pink circles in clusters which told me that this was gram negative cocci in clusters.

Finally is sample 4 which was taken from the recycling trash bin on the third floor. The macroscopic view showed several colonies growing they appeared to be yellowish-orange in color. All very close in size the largest measuring at .05cm and the smallest at .04 cm. the largest was slight raised with two circular shapes attached with a smooth surface and a white smooth margin. The smallest was elevated with a smooth texture and circular shape. When viewed under the microscopic I saw gram negative cocci. It was pink single circles. (

The agar plate that was “seeded” with the bacteria and had paper disk saturated with cleaner proved that the four cleaners I choose were at least partially effective with eliminating bacterial growth.

Bacteria are microscopic organisms whose single cells have neither a membrane-bounded nucleus nor other membrane-bounded organelles like mitochondria and chloroplasts. In my experiment I found both gram positive and gram negative bacteria. These bacteria’s can cause many illness and infectious diseases.

Gram-positive bacteria are those that are stained dark blue or violet by gram staining. This is in contrast to gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counter stain (safranin or fuchsin) and appearing red or pink. Gram-positive organisms are able to retain the crystal violet stain because of the high amount of peptidoglycan in the cell wall. Gram- positive cell walls typically lack the outer membrane found in gram-negative bacteria.

Gram-negative bacteria are those bacteria that do not retain crystal violet dye in the gram staining protocol. In a gram stain test, a counter stain (commonly safranin) is added after the crystal violet, coloring all gram-negative bacteria with a red or pink. The test itself is useful in classifying two distinct types of bacteria based on the structural differences of their cell walls. On the other hand, gram-positive bacteria will retain the crystal violet dye when washed in a decolorizing solution.

Some common illness or infectious diseases linked to gram positive bacteria are staph or strep which are the two most commonly linked illnesses. Some more serous diseases are Anthrax, Botulism, Diphtheria, Gas Gangrene, Rheumatic fever and Whipple’s diseases. Gram-positive can cause a wide variety of diseases in humans such as food poisoning, wound infection, Urinary tract infections, besides Pneumonia, Meningitis, Osteomyelitis, Endocarditis, Toxic shock syndrome (TSS), Diverticulitis, Septicemia, etc. (
Gram-negative bacteria can cause the following illnesses in humans Diarrhea, Gastroenteritis, Peritonitis, Septicemia, Pneumonia, Neonatal meningitis, Urinary tract infection, Typhoid fever, food poisoning, Ulcer, Upper and lower respiratory tract infection, burn and wound infection, Otitis media, Meningitis, Sexually transmitted disease like Gonorrhea and other infections of genital system, etc.

As just discussed both gram-positive and gram-negative bacteria can be extremely harmful. There are ways to prevent the infection of these bacteria’s. In today’s society there are several types of cleaning products that can be uses both on surfaces and on humans to prevent the spread of these bacteria. I tested four cleaners for their effectiveness on these bacteria. The cleaners that I used were povidone-iodine, Bactine, Dawn dish soap color yellow, and Mr.

Clean multi-surface.
Much of the information that I found regarding povidone-iodine shows that it is made for cleaning humans and sterilizing medical equipment, not for cleaning surfaces daily. Iodine is commonly used in topical disinfectant preparations for cleaning wounds, sterilizing skin before surgical/invasive procedures, or sterilizing catheter entry sites. Betadine solution, for example, contains povidone-iodine. Other topical disinfectants include alcohol and antibiotics and iodine is sometimes used in combination with these. Commercially prepared iodine products are recommended in order to assure appropriate concentrations. From my experiment this cleaner proved to be partially effective.

Bactine is also made to apply to humans. It is mainly used for first aid to prevent bacteria and other things from entering a wound and causing an infection. The manufacture says that Bactine Original First Aid Liquid has provided soothing infection protection for over 50 years. It relieves the pain and itch of minor cuts, scrapes and burns on contact as it kills germs. Plus, unlike hydrogen peroxide, it does not sting. From my experiment it proved to partially work.

During my experiment the Dawn dish soap color yellow was the most effective with cleaning and removing the bacteria that was planted in the agar plate. Ultra Dawn dishwashing liquid and Antibacterial Hand Soap helps fight germs on hands when used as a hand soap this statement is from the manufacture. Out of the four cleaners that I tested this is the most logical cleaner to use on surface to remove bacterial growth.

The final cleaner that was tested was Mr. Clean multi-surface. This cleaner proved to be effective with eliminating bacterial growth. The manufactures are very proud of this product give out helpful cleaning tips on ways to uses this product. Mr. Clean Multi-surfaces Spray Cleaner will help you remove grease, kill germs* and finish your surfaces off with a streak-free shine. It’s a great all-purpose spray cleaner for glass surfaces like mirrors and shower doors, as well as appliances like microwaves, stoves, refrigerators and more. In just a few sprays, you’ll be on to other things in a shining, clean and disinfected space.

This table is going to show the results of the cleaning products that were used during this experiment.
Name of cleaners: Povidone Iodine Bactine Dawn dish soap yellow Mr. Clean Multi-surface
Bacteria sample location: Stairway Railing third floor Stairway Railing third floor Stairway Railing third floor Stairway Railing third floor
Gram stain results: Negative Negative Negative Negative
Effectiveness: Partially Partially Completely Completely

The purpose of this Human Biology experiment was to find environmental growth throughout the campus of Mount Wachusett Community College. From my experiments I was able to find either gram-positive or gram-negative bacteria growing within four different locations of the college. Once the bacteria grew in the agar plate then “seeded” into another agar plate I was able to test four cleaners for their effect on eliminating those bacteria.

My hypothesis was proven to be correct because all four of the locations grew bacteria and all four of the cleaners were at least partially effective in removing the bacteria growing within the college.


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