I am a middle school science teacher, so I teach a variety of subjects including Physics, Biology, and Earth Science. I have found that the study of genetics is one of the more difficult concepts for this age to learn, so I ususallly spend a little bit of time on this. The basis of genetics starts inside of a the cell of a living creature, and inside that in the nucleus, and inside that on the chromosomes. As we know, DNA is located on those genes in the shape of a double-helix. I have my classes make a model of a portion of a DNA strand for extra credit, including the nitrogen bases, phosphates, deoxyribose, and they must point out that the nitrogen bonds (cytosine pairs with guanine, adinine pairs with thymine) are held together by a hydrogen bond and the sugar and phosphates are held together by a covalent bond. Also, I may be able to find some worksheets, or you can make your own, that are cutting and pasting different DNA components onto a DNA strand. It would not be hard to draw or find on your own, but I would be happy to send you one if you would like. If there are any questions, please reply to me at Jamer321@aol.com