![]() Helicase unwinds the DNA, and then an enzyme called polymerase copies it into an RNA molecule. For example, this happens when a cell wants to transcribe a gene into RNA. The DNA unzips like this for a couple of different reasons. Helicase can unwind DNA by breaking the bonds between base pairs, unzipping the two strands (Image via Shutterstock) Helicase moves along the DNA, breaking the bonds between base pairs to separate the strands of the double helix. And there is a special enzyme that does exactly that: DNA helicase. If a cell wants to use its DNA, it needs to unwind the double helix and access the base pairs. But what about when the cell needs to actually use those instructions? Most of the time, the instructions that DNA contains are safely stored away in a double helix. A molecule of DNA naturally twists to minimize how much water the base pairs touch (Image via Shutterstock) Opening the Double Helix? This gives us our familiar DNA double helix shape. The full ladder shape then naturally twists to better hide those bases away in the center. ![]() So the water-hating bases prefer to latch on to each other, with the outer backbone shielding them from the water. Fortunately, the outer backbone strands of DNA are hydrophilic and love water! Unfortunately, your cells are mostly made up of water, so the bases are surrounded by it. The chemical properties of DNA cause it to adopt this shape naturally.įirst, the base pairs themselves are hydrophobic. That means they want to avoid contact with water. The bases from each strand match up in the middle to link together, with A pairing with T and C pairing with G. Each strand will have nucleotide bases sticking out of it - those famous letters of A, T, C, and G. This is made up of two strands running in opposite directions. DNA’s Twists and TurnsĭNA is most often found in the classic double helix shape. Then, we’ll get into why it sometimes takes other shapes. But DNA, the all-important blueprint for making up who we are, definitely does not always take this shape!įirst, let’s look into why DNA is a double helix in the first place. Yes! Most people have probably seen DNA depicted as a double helix, with two chains twisting around each other to make a spiral staircase structure.
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