Open the combination lock using the old combination. Remove the u-bar from the lock body so it's in the Unlock position. Use a screwdriver to open the anti-dust cover on the back of the combination lock. Align the old combination numbers to the guide points.
A base pair (bp) is a unit consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix, and contribute to the folded structure of both DNA and RNA.
Types of Base Pairs. Each nitrogenous base has a partner. In DNA, adenine and thymine pair up, and so do guanine and cytosine. In the related molecule RNA, thymine is replaced by its close relative uracil, so the pairs are adenine-uracil and guanine-cytosine.