Suppose I cut a human DNA molecule that was 6800Å long into 5 equal sized pieces using molecular scissors, how can I find out number of nucleotides in each of the cut pieces? Please give a bit detailed solution. I'm kinda new to these kind of questions.


closed as off-topic by David, kmm, WYSIWYG Feb 5 at 15:25

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  • $\begingroup$ This is a homework question. Such questions are considered on-topic only if a significant effort has been made by the asker towards finding out the answer. Moreover, if we do your homework for you then what will you learn? $\endgroup$ – WYSIWYG Jan 29 at 9:15
  • $\begingroup$ What kind of efforts do you expect? Moreover, I am in my 10th grade and have very little knowledge on this topic. (And this is not a HOMEWORK question. I found these sort of questions in bunch of question papers).That was why I mentioned that I was new to these questions and I needed a bit of explanation .SideNote: This is not even in my School Textbooks and I am asking this out of my own interest. I failed to find a concrete answer to this question online (if there exists one, please post it.) $\endgroup$ – Yellow Jan 29 at 10:26
  • $\begingroup$ At least in Math, I can tell people what formulae or theorems I`ve used. What do you exactly mean by efforts here? (Please tell, I am new.) $\endgroup$ – Yellow Jan 29 at 10:31
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    $\begingroup$ @WYSIWYG is a moderator on this SE Group (you can tell by the diamond). He is explaining to you as a new user how the site works. The answer to your question "What kind of efforts do you expect?" is given in the Help on asking questions which we expect you to make the effort to read. The fact that you are still at school is really irrelevant. If you read the tour you will see that "Biology Stack Exchange is a question and answer site for biology researchers, academics, and students". If you don't fit, don't post. $\endgroup$ – David Jan 29 at 13:38

Angstroms are a measure of distance. 1 angstrom is a tenth of a nanometer, i.e. 10 nanometers make 1 angstrom.

Your DNA molecule: 6800 A

Cut into 5 equal pieces: 6800/5 = 1360

Each cut DNA piece is 1360 A long.

A DNA helix has the following properties: 10 base pairs extend 34 A.

1360/34 = 40 = how many '10 base pairs' of length you have in each cut DNA piece.

If a cut piece has forty 10 base pairs of length, the full length has 40 * 10 bp.

40 * 10 = 400 bp.

Each cut piece is 400 bp long. The original DNA piece, uncut, is five times the size of its cut. In other words, the original DNA piece is (400 * 5) 2000 bp long.


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