Why is DNA shaped as a spiral?
-A high school student from Australia Almost everybody who talks about DNA can tell you it is double stranded. And that it forms a twisted ladder or a double helix. But few people can tell us why. DNA is a spiral for a number of reasons that have to do with what it is made of. Let’s dig deeper, break open the DNA and figure out why it is put together in that shape. DNA has three parts—sugar, phosphate and bases that are linked together chemically in a particular way. Surprisingly, a big part of what makes DNA a spiral has to do with how well each part dissolves in water! Turning DNA into a staircase The sugar molecule is like the sugar we use in our foods. To sweeten our coffee or lemonade, sugar has to dissolve in water. When something can dissolve in water, it is called “water-soluble” or hydrophilic. Phosphates aren’t as well known as sugars but they are really important for our body. They are also used in baking mixes, fertilizer, and lots of other things. To be used in these ways,
