Question

5. You grow a culture of E. coli to an OD reading of 0.8. Your instructor...

5. You grow a culture of E. coli to an OD reading of 0.8. Your instructor wants 40 colonies on a plate. Ideally, you want to only spread 100ul on a LB plate. How would you carry out the proper dilutions in order to arrive at 40 cells on a plate? Please show your calculations and all work. (1 O.D. = 1 x 108 cells/mL).

0 0
Add a comment Improve this question Transcribed image text
Answer #1

Volume plated = 100uL

Number of colonies =40 colonies

Step 1: Convert O.D to cfu/ml

(O.D of 0.8) x (1x 10^8) / (1 O.D) = 8 x10^ 7 cfu/ml

Step 2: Number of bacteria/mL= Number of colonies * Dilution of the sample

  Number of colonies * Volume plated * Total dilutions used

8 x10^ 7 cfu/ml = 40 colonies * 0.1 ml * Total dilutions

Total dilutions=   8 x10^ 7 cfu/ml) / ( 40 colonies) * (0.1 ml) = 32 X10^7

Add a comment
Know the answer?
Add Answer to:
5. You grow a culture of E. coli to an OD reading of 0.8. Your instructor...
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for? Ask your own homework help question. Our experts will answer your question WITHIN MINUTES for Free.
Similar Homework Help Questions
  • 2a. (4 pts) A potent mutagen was added to an E. coli culture growing in rich...

    2a. (4 pts) A potent mutagen was added to an E. coli culture growing in rich broth. Prior experiments established that this F cell line, designated WWU113, could not synthesize leucine. You are interested in measuring the rate of induced reverse mutation. You plan to grow a liquid culture of the leu strain and then plate various dilutions of the culture onto selective media. What media should you use to grow up the liquid culture? This will be Media A...

  • The adaptation phase for the E. coli culture lasted A culture of E. coli was grown...

    The adaptation phase for the E. coli culture lasted A culture of E. coli was grown on suitable culture media; aliquots of the culture were serially diluted and spread plated aseptically on agar plate media at the times indicated in the table below. Upon overnight incubation at 37°C, colonies appeared and viable counts were colleted and displayed below. Hours 0 Viable Counts (CFU/mL) 2 .00 x 107 2.10 x 107 2.30 x 107 3.25 x 107 6.60 x 107 1.40...

  • You have a stock of an E. coli cell culture of an unknown concentration. You want...

    You have a stock of an E. coli cell culture of an unknown concentration. You want to set up a serial dilution experiment so that you can count the viable colonies and determine the concentration of the stock in cells/ml. In tube A, you add 1 ml of the stock to 999 ml of media. In tube B, you add 1 ml of the material from tube A to 24 ml of media. In tube C, you add 50 microliters...

  • You want to dilute and plate an E. coli culture that has 3 *10 8 cells/ml....

    You want to dilute and plate an E. coli culture that has 3 *10 8 cells/ml. If you needed to dilute the above culture, starting from the undiluted stock, to a concentration of 500 cells/ml, how could you perform a serial dilution to achieve the desired final concentration?

  • a) During the exponential phase of bacterial growth, the lab strain of E. coli has doubling...

    a) During the exponential phase of bacterial growth, the lab strain of E. coli has doubling time of about 30 minutes. If you start with 10,000 cells per mL of culture, and let them grow exponentially 2 hours in a flask, what is the final density of the culture? Show and explain your calculations. b) If you plated a100μL of 1:1000 dilution that culture (after it had grown in a flask for 2 hrs) how many colonies would you expect...

  • After measuring the OD (see question 5) of an S.aureus bacterial culture, you find that the...

    After measuring the OD (see question 5) of an S.aureus bacterial culture, you find that the concentration is too high and perform a 1:1 dilution. In order to reach a final volume of 1000uL in your cuvette, what combination of bacterial culture and fresh media must be combined to achieve the desired dilution? If the OD after the dilution is 0.54, what was the undiluted OD? (question 5: After you have grown a culture of E. coli bacteria, you measure...

  • A. You have been given a tube of E. coli. You are asked to make 1...

    A. You have been given a tube of E. coli. You are asked to make 1 mL total volume of 10-1 dilution of the bacterial culture. Explain how you would do this. Show all necessary calculations. ____ ml cells   +    _____ ml water    = 1 ml    (total volume) B. Next, you were asked to make a 10-2 dilution of the bacterial sample. Explain how you would perform this. Show all necessary calculations. You have bacteria at a concentration of 2...

  • 6. Transposon mutagenesis was performed to identify genes that are involved in the biosynthesis of theA amino acid alanine. A wildtype culture of E. coli was infected with a defective phage carrying...

    6. Transposon mutagenesis was performed to identify genes that are involved in the biosynthesis of theA amino acid alanine. A wildtype culture of E. coli was infected with a defective phage carrying Tn10 A and the culture was plated on LB-tet media to obtain tet-resistant colony forming units. (LB is a rich growth media for E. coli and contains all amino acids required for bacterial growth) Individual CFU were then transferred to a multiwell plate containing liquid LB-tet media and...

  • Please show how to do these enumeration questions by showing the work. What is the dilution...

    Please show how to do these enumeration questions by showing the work. What is the dilution factor if you add 625 µL of culture to 4.375 mL of dilution medium? You count the 10-3 dilution of a yeast suspension using the 1/25 mm2 boxes : you find 45 cells in box 1, 15 cells in box 2, 42 cells in box 3, 23 cells in box 4, and 26 cells in box 5. a) What is the original concentration of...

  • 14. You inoculated a 1 mL tube of sterile LB broth with E. coli, and let...

    14. You inoculated a 1 mL tube of sterile LB broth with E. coli, and let it grow @37C overnight. The next day you extracted a total of 2.15 ug of DNA from this culture. Calculate how many cells were in that 1 mL of culture? (Hint: Use the value derived above to do this calculation). 5 points 15. If you assume that your 2.15 ug of DNA isolated from E. coli had an average length of 10,000 bp, approximately...

ADVERTISEMENT
Free Homework Help App
Download From Google Play
Scan Your Homework
to Get Instant Free Answers
Need Online Homework Help?
Ask a Question
Get Answers For Free
Most questions answered within 3 hours.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT