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.
This means that only two kinds of base pairs are possible: GC (or CG) and AT (or TA). This specific arrangement of the nitrogenous bases is known as complementary base pairing and is a key principle of DNA organization. To unlock this lesson you must be a Study.com Member.