Virtual Lab: Testing Antibacterial Agents Name ______

Site: Classzone.com. Click on Biology Georgia 2008, then Virtual Labs, then Testing Antibacterial Agents

Do not print any of the pages from the computer. Place all of your answers on this sheet. You may have to fill in the log book but DO NOT print.

1. What is the purpose of this lab activity? ______

______

2. What is the purpose of the incubator? ______

______

3. Go to Background Information. Answer the following.

a. Bacteria that cause disease are called ______.

b. Most pathogens that enter the body are prevented from multiplying by the ______

______.

c. ______are substances that prevent bacterial growth.

d. ______are substances that are taken internally or

applied to the body to treat bacterial infections.

e. ______are bacterial agents that are safe enough to

apply to the skin, but not taken internally.

f. ______are substances used to clean surfaces but not

safe enough to apply to living tissues.

4. Predict whether each of the antibacterial agents will be E Effective, SE Somewhat Effective, or NE not effective in killing the bacteria.

Rate Test Substance Mouthwash Hydrogen Peroxide Bleach Household Disinfectant Alcohol Hand Soap

5. What is the control in the experiment? ______

6. After all of the disks have been soaked in the antibacterial agents and placed in the petri dishes, how long are they incubated? ______7. Why are the petri dishes stored upside down in the incubator? ______8. After the incubation period, you can click on the petri dishes to enlarge them. A clear area around the disk indicates no growth or that the bacterial agent on the disk is preventing the growth of bacteria. In the example below, A is effective, B is somewhat effective and C is not effective at all. ***Print the page to include with your answer sheet to be turned in.

In the chart below, indicate: NE NOT EFFECTIVE: normal growth (no clear areas around the disk) SE SOMEWHAT EFFECTIVE: less growth ( a narrow margin around the disk) E EFFECTIVE: no growth (a ring of clear area around the disk)

Rate Test Substance Mouthwash Hydrogen Peroxide Bleach Household Disinfectant Alcohol Hand Soap

9. According to your results, what was the best antibacterial agent to use against the bacteria? ______

10. Which ones were somewhat effective? ______

11. Which ones were not effective at all? ______

12. Did the results match your predictions? Explain. ______

13. Which of the agents that you tried are: (a) antiseptics ______

(b) antibiotics ______

14. Based on your observations, can you accurately predict how effective the antibacterial agents used in this investigation will be against different types of bacteria? Explain. ______15. In this experiment, identify the (a) independent variable ______

(b) dependent variable ______