5) You have prepared two spread plates (as shown below) using 0.1 mL from a liquid culture of E. coli at an unknown concentration. Count the colonies that have grown and use that information as well as the total dilution factor for the corresponding plate to calculate the average original concentration of your suspension. TDF: 8.0 x 10^7 TDF: 5.0 x 10^8
Added by John M.
Close
Step 1
Step 1: Calculate the average original concentration for plate 1. Show more…
Show all steps
Your feedback will help us improve your experience
Sri K and 61 other Biology educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
You diluted a starting culture of E. coli 1:10 ten times. From these dilutions you plated 0.1mL of each dilution onto an agar plate. You then counted the number of bacterial colonies that grew after incubation (see below). Give the average estimated starting concentration of bacteria per milliliter from the plates shown below. Don't forget units! Show your work. 1 x 10^-9 dilution (1/1,000,000,000) 1 x 10^-10 dilution (1/10,000,000,000)
Shaiju T.
You have the following sample of E. coli that was serially diluted. 0.1 0.1 0.1 0.1 1.0 1.0 sample 9.9ml 9.9ml 9.9ml 9.9ml 9.0ml 9.0ml A. What is the dilution of E. coli in tube #6? I am not asking for the individual dilution in test tube #6, I am asking what is the dilution of the sample by the time it is in tube #6? (1) B. You prepare pour plates using the last 4 dilution, dispensing 1.0 ml of the dilution into each plate. After incubating the plates you have the following results: Plate 3: too many colonies to count Plate 4: 5680 colonies Plate 5: 720 colonies Plate 6: 137 colonies Determine the concentration of E. coli in the original sample. Don't forget to include your units and use scientific notation. (2)
Jenny W.
You perform 1 to 10 serial dilutions of a microbial culture and spread plate 100ul of the diluted culture. After incubation, the plate counts are: 10-0 TNTC 10-1 TNTC 10-2 490 colonies 10-3 53 colonies 10-4 8 colonies 10-5 TFTC Using the formula found in the video (or lab #4 background information), what is the concentration of the original culture? 5.3 x 10e4 CFU/ml 4.9 x 10e3 CFU/ml 490 x 10e3 CFU/ml 53 x 10e3 CFU/ml 4.9 x 10e4 CFU/ml 4.9 x 10e5 CFU/ml 5.3 x 10e5 CFU/ml
Dominador T.
Recommended Textbooks
Biology for AP Courses
Objective Biology for NEET
Introduction to General, Organic and Biochemistry
Transcript
18,000,000+
Students on Numerade
Trusted by students at 8,000+ universities
Watch the video solution with this free unlock.
EMAIL
PASSWORD
