-1
$\begingroup$

You are to non-culturally detect the presence of E. coli in the soil from a cow pasture. You do this by extracting the total DNA from a sample of the soil and PCR amplifying with E. coli-specific primers that bind to a gene only found in E. coli that amplify a region of the DNA 167 bp long. Propose a postive sample that could be tested alongside your experimental sample.

A. Known Shigella DNA

B. Water

C. Number of Injections

D. Muscle DNA

E. Known E. coli DNA

I think the answer is (E) Known E. coli DNA. That would be the positive control in this context. For a positive control, you need something that you would know the response for. E. coli specific primers would amplify the known E. coli DNA. Water is obviously wrong. I could be wrong. Am I missing something?

|improve this question
$\endgroup$
  • 4
    $\begingroup$ To the homework close voter: this user has made an attempt to answer, so has fulfilled the requirements of the homework policy. $\endgroup$ – De Novo Mar 18 at 6:13
1
$\begingroup$

Yes, you're correct. The question is asking for a positive sample that would be amplified by E. coli specific primers. Known E. coli DNA would do the trick.

|improve this answer
$\endgroup$
  • $\begingroup$ Thank you for the clarification!!!! $\endgroup$ – user50592 Mar 18 at 6:22
  • $\begingroup$ @user50592 you're welcome. If you'd like to mark this as the answer, click the gray checkmark next to it. I would also recommend you take the tour and visit help center to learn about this stack exchange site. $\endgroup$ – De Novo Mar 18 at 6:26

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.