1. Plate count data are used to calculate microbial population density as colony forming units (CFUs) per milliliter of culture. Culture density (CFU/mL) = number of colonies (dilution factor) x (volume plated, in mL) Use these data below to calculate the CFU/mL in this sample of bacteria after 1 hr of growth. **Important to know for these types of questions - only use colony counts that fall between 10 and 300. TNTC = too numerous to count, so many colonies that you can't distinguish them to count. Use the plates with numbers of colonies that can be counted, calculate the CFU on each one, and then calculate the average between all of them. Looking for more assistance? Read section 7.3 in the textbook. Time 1h Dilution (before plating) none 1:10 (1 x 10-¹) 1:100 (1 x 10-²) 1:1,000 (1 x 10-³) Volume spread on plate 0.1 mL 0.1 mL 0.1 mL 0.1 mL Number of colonies observed (replicate plates) TNTC 499 83 10 TNTC 518 87 8 TNTC indicates too numerous to count. *Cell density could not be calculated accurately because plates contained too many colonies to be counted, too many colonies to be counted accurately (>300), or too few colon to be meaningful (<10)

1. Plate count data are used to calculate microbial population density as colony forming units (CFUs) per milliliter of culture. Culture density (CFU/mL) = number of colonies (dilution factor) x (volume plated, in mL) Use these data below to calculate the CFU/mL in this sample of bacteria after 1 hr of growth. **Important to know for these types of questions - only use colony counts that fall between 10 and 300. TNTC = too numerous to count, so many colonies that you can't distinguish them to count. Use the plates with numbers of colonies that can be counted, calculate the CFU on each one, and then calculate the average between all of them. Looking for more assistance? Read section 7.3 in the textbook. Time 1h Dilution (before plating) none 1:10 (1 x 10-¹) 1:100 (1 x 10-²) 1:1,000 (1 x 10-³) Volume spread on plate 0.1 mL 0.1 mL 0.1 mL 0.1 mL Number of colonies observed (replicate plates) TNTC 499 83 10 TNTC 518 87 8 TNTC indicates too numerous to count. *Cell density could not be calculated accurately because plates contained too many colonies to be counted, too many colonies to be counted accurately (>300), or too few colon to be meaningful (<10)

Comprehensive Medical Assisting: Administrative and Clinical Competencies (MindTap Course List)

6th Edition

ISBN:9781305964792

Author:Wilburta Q. Lindh, Carol D. Tamparo, Barbara M. Dahl, Julie Morris, Cindy Correa

Publisher:Wilburta Q. Lindh, Carol D. Tamparo, Barbara M. Dahl, Julie Morris, Cindy Correa

Chapter42: Basic Microbiology

Section: Chapter Questions

Problem 4CR

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