Constructing a DNA modelThe FIB 10JGo class constructed a DNA model that could be stretched from the third storey in our school all the way down to the first storey, almost touching the ground (see photo below). For the construction, we made about 200 small circular phosphate molecules, 200 pentagonal sugar molecules and 400 rectangular base molecules!!
It was a fun and lively activity, but we did learn a lot about DNA. Or at least, we could cope well with Ms. Carter’s questions afterwards.
DNA stands for deoxyribonucleic acid. We are familiar with DNA in relation to inheritance. For example, we know that DNA has something to do to why offspring often have their parents’ characteristics. Well, that’s correct because DNA is a nucleic acid molecule that carries genetic instructions that is found in all living organisms except some viruses.
In cells of eukaryotic organisms (which have a nucleus in their cells), DNA is found inside the nucleus. Animals (humans are included here), plants, fungi and protists are eukaryotes, so they have their DNA inside their nucleus. Since bacteria do not have a nucleus, they are prokaryotes and their DNA is found in cytoplasm.Now, look at the photo below. It’s a close-up look at our DNA model. The colourful rectangles represent base molecules and contain either one of these letters: T, A, G or C. T stands for thymine, A for adenine, G for guanine and C for cytosine. Notice that T only pairs up with A and G with C. This is the rule of base pairing, i.e. the bases will always pair up this way. Each pair of bases is held together by hydrogen bonds (see the staple between two bases).
DNA stands for deoxyribonucleic acid. We are familiar with DNA in relation to inheritance. For example, we know that DNA has something to do to why offspring often have their parents’ characteristics. Well, that’s correct because DNA is a nucleic acid molecule that carries genetic instructions that is found in all living organisms except some viruses.
In cells of eukaryotic organisms (which have a nucleus in their cells), DNA is found inside the nucleus. Animals (humans are included here), plants, fungi and protists are eukaryotes, so they have their DNA inside their nucleus. Since bacteria do not have a nucleus, they are prokaryotes and their DNA is found in cytoplasm.Now, look at the photo below. It’s a close-up look at our DNA model. The colourful rectangles represent base molecules and contain either one of these letters: T, A, G or C. T stands for thymine, A for adenine, G for guanine and C for cytosine. Notice that T only pairs up with A and G with C. This is the rule of base pairing, i.e. the bases will always pair up this way. Each pair of bases is held together by hydrogen bonds (see the staple between two bases).
The DNA model above looks like a ladder. The phosphates (represented by the yellow circles) join up with sugar molecules (the pentagons) and they make up the uprights of the ladder; the bases make up the rungs. We further twisted the model above into a beautiful double helix (the molecular structure of an actual DNA molecule), so it looked like a spiral staircase.
Petrus Bosa Layarda
