Restriction enzyme reads a DNA strand containing nucleotide base pairs

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Discussion Overview

The discussion revolves around a homework question regarding the behavior of a restriction enzyme that reads a specific DNA sequence of 6 base pairs (AAGCCT) and its implications for the average length of a cut DNA strand. The scope includes mathematical reasoning and conceptual clarification related to biology and genetics.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • The original poster suggests calculating the average length of a cut strand using the probability of the enzyme reading the correct base, proposing the formula (1/4)^6.
  • One participant questions the appropriateness of posting biology questions in a physics forum and expresses concern about the lack of biology experts available to assist.
  • Another participant raises questions about the randomness of the DNA sequence and whether the direction of reading the sequence (left to right vs. right to left) affects the outcome, suggesting that the enzyme may work from both ends.
  • A further reply emphasizes the need for more context regarding the problem, questioning whether the inquiry is about the distance between restriction sites or the occurrence of the sequence within a longer random DNA strand.

Areas of Agreement / Disagreement

Participants express differing views on the clarity and context of the original question, with some seeking more information while others highlight the challenges of addressing biology questions in a physics-focused forum. No consensus is reached regarding the calculation or the nature of the problem.

Contextual Notes

The discussion lacks specific information about the length of the DNA strand and the context of the problem, which limits the ability to provide a definitive answer regarding the average length of a cut strand.

BassMaster
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Homework Statement



I know this is a biology question but this is the most busy forum so I decided to put it here:

I'll make this simple. A restriction enzyme reads a DNA strand containing nucleotide base pairs. It cuts the strand after it reads a sequence of 6 base pairs - AAGCCT. Of course the probability of the enzyme reading the correct base is 1/4. And it needs 6 of them.

So what is the average length of a cut strand? I'm thinking you do (1/4)^6 and this will give you something.. but what?

Thanks for your help in advance...



Homework Equations





The Attempt at a Solution

 
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Please put the questions on the correct forum. Our mods will just have to move it and theyre over worked as it is.:smile:
Sorry can't help you with Biology. Thats also a problem, the biology people don't come here to answer bio questions.
 
Last edited:
I'm more of a physics and math person than a bio person, but two questions: Is this DNA that's competely random? (from the math point of view), and the bigger question: Does it matter which end you're coming from? i.e. if you had a strand that was CCAAGGTCCGAATAGC, although AAGCCT doesn't appear from left to right, it does appear when going from right to left. (My bit of knowledge makes me believe it can work from both ends)
 
Okay, forget making it "simple." Can you give your problem exactly as it was given to you? What is the context? The length of a cut strand is the distance between the restriction sites, so there isn't enough information provided about what it is you're cutting to know that.

Or, are you trying to find the probability of that exact 6 nucleotide sequence occurring more than once in a random sequence? Without being given any information about the length of the DNA strand, you have to assume they're talking about the distance between two restriction sites and not from a restriction site to the end of the DNA.

So, please come back with some clarification of what the problem is, or we can't do much to help.
 

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