Microbiology Lab Study Guide PDF

Table 3- Anali, Jasmine, Ikenna, and Earl. **Lab 8** Koch's pt 1- 1. **Identify Koch's Postulates** - The microorganism must be found in all organisms suffering from the disease, but not in\ healthy organisms. - The microorganism must be isolated from a diseased organism and gr...

Table 3- Anali, Jasmine, Ikenna, and Earl. **Lab 8** Koch's pt 1- 1. **Identify Koch's Postulates** - The microorganism must be found in all organisms suffering from the disease, but not in\ healthy organisms. - The microorganism must be isolated from a diseased organism and grown in pure culture. - The cultured microorganism should cause disease when introduced into a healthy organism. - The microorganism must be again isolated from the inoculated, diseased experimental host\ and identified as identical to the original specific causative agent. 2. **What did the milk and yogurt represent in the Koch's postulate lab?** Milk represented the healthy individual and yogurt represented the diseased individual. Pt 2- 3. **What was the point of the ampicillin in the Koch's postulate lab?** Adding ampicillin, which is an antibiotic, would not allow the growth of bacteria. So, the yogurt with the addition of ampicillin to the milk would not allow the growth of bacteria. Pt 3- 4. **What's the importance of using only one colony to inoculate the milk and not multiple colonies in the Koch's postulate lab?** 5. **Is it possible that the bacteria may not be able to grow due to not having the right environment to grow?** **Lab 9** 1. **What is the purpose of forming serial dilutions in this experiment?** It reduces the concentration of bacteria which will then ensure the number of colonies on the agar plate is within countable range. 2. **What is the formula used to calculate CFU/mL?** CFU/mL= (Number of colonies/ Volume plated (mL)) x Dilution factor 3. **Why is vortexing necessary during serial solution** It helps ensures thorough mixing of bacterial cells which will then give an accurate representation of the dilution process and uniform plating 4. **How does the concentration of a bacterial culture change with each step in a serial dilution?"** The bacteria culture decreases systematically with each dilution step. **5. What are the consequences of contamination during the serial dilution process?** Contamination during serial dilution can result in inaccurate CFU/mL calculations, misinterpretation of microbial diversity, and invalid experimental results.