Name(s): Period: Date: Purpose The goal of this lab will be to collect, culture, and observe some of the normal flora in the mouth and skin of the human body. Your lab team will also decide on an “environmental change” to test on the normal flora, and observe how this change impacts the populations and species that grow on the nutrient agar plate. Materials Petri plate w/ nutrient agar (2) Cotton swabs Permanent marker Skin “environmental change” Mouth “environmental change” Procedure Your lab team will be given tasks, or directions, to perform on the left. Record your questions, observations, or required response to each task on the right. Part A. Preparing the Plates Task Response 1 Obtain 2 petri plates. Your instructor has already poured nutrient agar into the petri plates, or if not will provide instruction. DO NOT OPEN YOUR PLATE UNTIL DIRECTED! 2 Using the permanent marker, label the top of one plate “Skin” and include your group name (see upper image). 3 Notice the plate is split into two sides. On the bottom of the plate, in very small writing, write “A” on one side and “B” on the other as close to the edge as possible. You do not want to have to look through your labeling to see what grows on the plate. 4 Using the permanent marker, label the top of the other plate “Mouth” and write your group name. 5 Notice this plate is also split into two sides. On the bottom of this plate, in very small writing, write “A” on one side and “B” on the other as close to the edge as possible. 6 Choose one individual in your group to be the test subject. 7 Have the test subject swirl a cotton swab in his or her mouth for at least 5 seconds. Whenever removing the lid from the plate, it is Ecosystems of the Body, HASPI Medical Biology Lab 10 Skin Group E A B 297
Transcript
Name(s): Period: Date:
PurposeThe goal of this lab will be to collect, culture, and observe some of the normal flora in the mouth and skin of the human body. Your lab team will also decide on an “environmental change” to test on the normal flora, and observe how this change impacts the populations and species that grow on the nutrient agar plate.MaterialsPetri plate w/ nutrient agar (2) Cotton swabs Permanent markerSkin “environmental change” Mouth “environmental change”
ProcedureYour lab team will be given tasks, or directions, to perform on the left. Record your questions, observations, or required response to each task on the right.Part A. Preparing the Plates
Task Response1 Obtain 2 petri plates. Your instructor has already poured nutrient agar into the petri
plates, or if not will provide instruction. DO NOT OPEN YOUR PLATE UNTIL DIRECTED!2 Using the permanent marker, label the top of one plate
“Skin” and include your group name (see upper image).
3
Notice the plate is split into two sides. On the bottom of the plate, in very small writing, write “A” on one side and “B” on the other as close to the edge as possible. You do not want to have to look through your labeling to see what grows on the plate.
4 Using the permanent marker, label the top of the other plate “Mouth” and write your group name.
5Notice this plate is also split into two sides. On the bottom of this plate, in very small writing, write “A” on one side and “B” on the other as close to the edge as possible.
6 Choose one individual in your group to be the test subject.
7 Have the test subject swirl a cotton swab in his or her mouth for at least 5 seconds.
8Whenever removing the lid from the plate, it is important to not remove the lid completely! Hold the lid over the plate. Contaminants in the air can easily settle and grow in the dish if the lid is completely removed.
9 The nutrient agar in the plate is similar in consistency to Jello. Try not to break the surface of the agar.
10
On side A of the “Mouth” plate, starting at the middle, very gently brush the cotton swab back and forth in a zig-zag motion (see lower image).
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Remove and discard the cotton swab. Place the lid back on the plate.
Ecosystems of the Body, HASPI Medical Biology Lab 10
SkinGroup E
A
B
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Name(s): Period: Date:
12
Choose an “environmental change” for the mouth. Suggestions include: mouthwash, soda, food, or anything else that could be placed and moved around in the mouth.
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Have the test subject put the choice in his or her mouth, and swish around the “environmental change” for 30 seconds. For example, a soda can be swished just like a mouthwash. After 30 seconds, spit the choice into the sink or trash.
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Immediately have the test subject swirl a cotton swab in his or her mouth for at least 5 seconds.
15
On side B of the “Mouth” plate, starting at the middle, very gently brush the cotton swab back and forth in a zig-zag motion (see image). Remember not to break the agar.
16
Remove and discard the cotton swab. Place the lid back on the plate, and set the plate aside.
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Choose one individual in your group to be the test subject for the “Skin” activity.
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Whenever removing the lid from the plate, it is important to not remove the lid completely! Hold the lid over the plate. Contaminants in the air can easily settle and grow in the dish if the lid is completely removed.
19
Remember, the nutrient agar in the plate is similar in consistency to Jello, so you are trying to avoid breaking the surface of the agar here as well.
20
On side A of the “Skin” plate and starting at the middle, have the test subject very gently brush an index finger back and forth in a zig-zag motion. Place the lid back on the plate.
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Choose an “environmental change” for the skin. Suggestions include: lotion, soap, disinfectant, or anything else that could be used on the skin.
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Have the test subject put the choice on both hands, and wait for 3 minutes. For example, if the choice is lotion, have the test subject apply lotion to the hands in the usual way.
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On side B, starting at the middle, have the test subject very gently brush the index finger back and forth in a zig-zag motion. Place the lid back on the plate.
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Turn both plates in to the instructor. If an incubator is available, the bacteria and fungus will have grown by the following day. If not, it will be 2-3 days before the plates will be ready for observation.
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Name(s): Period: Date:
Part B. Observing the PlatesTask Response
1 Collect your plates. DO NOT REMOVE THE LIDS FROM YOUR PLATES!!!
Draw the growths that appear on each plate below. Mouth
Table 1. Normal Flora Growth: MouthSide A, B, or both?
Description Abundance
(how many)
Skin
Table 2. Normal Flora Growth: SkinSide A, B, or both?
Description Abundance
(how many)
2
Observe the bacterial and fungal growths on the plates. Bacterial growth will be evidenced by small round colonies, while fungal growths normally have a more complex structure, variety of colors, and can even look like mold. Record your observations on the right; use color if needed.
3
Record in Table 1 and Table 2 how many different types of organisms appeared, with a description of each on sides A and B of the respective plate. If there are more than 5 organisms, continue Tables 1 and 2 in the space below.
Once finished, return the plates to your teacher for disposal.
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Name(s): Period: Date:
Analysis & Interpretation
Connections & ApplicationsYour instructor may assign or allow you to choose any of the following activities. As per NGSS/CCSS, these extensions allow students to explore outside activities recommended by the standards.
1. RESEARCH MICROBIOTA INTERACTIONS: Species within ecosystems interact with one another, even on the microscopic level. Specific interactions, such as predation, competition, and symbiosis occur between microbiota. Corynebacterium and Staphylococcus are two families of bacteria that commonly colonize the human body. Use the Internet to research and answer the following questions. Cite ALL of your references.
a. Provide two specific species of Corynebacterium and Staphylococcus that colonize the human body.
b. What part of the human body does each family colonize?c. How does each family live in symbiosis with the human body? Provide a
specific example.d. How do these two families interact with one another? Provide a specific
example.e. Can species from either of these families cause disease? How?
2. HUMAN MICROBIOME PROJECT: The Human Microbiome Project (HMP) is a large-scale research project aimed at discovering and sequencing all of the microorganisms that make up the human microbiome. Using the Internet, research and answer the following questions related to the HMP. Cite your references.
a. What is the Human Microbiome Project, and why is it important to health and medicine? Give at least three examples.
Ecosystems of the Body, HASPI Medical Biology Lab 10
Analysis Questions – answer questions on a separate sheet of paper1. What environmental change was chosen for the skin plate? Be specific
(brand/variety).2. How did the environmental change impact the population and/or types of
growths that appeared on the skin plate?3. If the environmental change were to be consistently used (i.e. daily or hourly
use), do you think it could change the environment and biodiversity of the skin? Explain your answer.
4. What specific environmental change was chosen for the mouth plate? (Brand/flavor)
5. How did the environmental change impact the population and/or types of growths that appeared on the mouth plate?
6. If the environmental change were to be consistently used, do you think it could change the environment and biodiversity of the mouth? Explain your answer.
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Name(s): Period: Date:b. How many microorganisms that are part of the human microbiota have
currently been identified?c. Summarize at least two articles that outline how the HMP has provided
insight or implications on human health.3. GRAPHICAL COMPARISONS OF MICROBIOTA: Graphical comparisons of
biodiversity and populations in ecosystems can assist researchers in predicting interactions between species. Two species of bacteria, Bacillus subtilis and Staphyloccus aureus have been found in the nasal passageways of humans. In an experiment to determine how these two bacteria interact with one another, B. subtilis and S. aureus were grown in petri plates both independently and also together. The numbers of organisms in the populations were counted at 12-hour intervals for a week. The data collected can be found in Table A below. Create a single graph to represent the data in Table A, and then answer the questions below. (Title/label your graph!)Table A. Bacterial Species Growth Rate
Time Grown Separately Grown TogetherB. subtilis S. aureus B. subtilis S. aureus
