Quick and easy way to demonstrate basic DNA structure

27 Nov

Here’s  a quick and easy way to get your students out of their desks for just a few minutes and demonstrate DNA structure at the same time.  It will also take very little preparation time on the part of the teacher, too (always a bonus).  This should be done after discussing the basics about DNA:

  • It’s a nucleic acid.
  • It’s made of monomers called nucleotides.
  • Each nucleotide in DNA has 3 parts–a 5 carbon sugar, a phosphate group, and a nitrogenous base.
DNA

DNA

Give about half of your students a nitrogenous base.  You can either write the letters A, T, C, G on notecards and tell the students the base-pairing rules, or you can get more elaborate and create complementary shapes for A and T, and C and G and have them figure it out.

anti-parallel
Line up these students with bases and tell them to place the base in their left hand and hold it out to the side.  They must then put their right hand on the shoulder of the person in front of them.  Their bodies represent the 5 carbon sugar (deoxyribose) and their right hand stretching out represents the bond holding the backbone of the molecule together. 

Next, tell your other students to grab a base and line up next to the others to create the complementary strand.  They will automatically try to put the bases in their right hand and stand facing the same direction as the original line of students.  Say, “No, remember, the bases should be in your LEFT hand.”  After a puzzled moment, they’ll figure out that they have to face the opposite direction to make this work, and then you can tell them that they’ve just demonstrated one of DNA’s most important properties–the strands are anti-parallel.  🙂

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