Which pair of nitrogenous bases will form a bond in a DNA molecule?
thymine and cytosine
guanine and thymine
cytosine and adenine
adenine and thymine
adenine and thymine
In a DNA molecule, the nitrogenous bases that form a bond are adenine (A) and thymine (T), and guanine (G) and cytosine (C). Therefore, the correct pair of nitrogenous bases that will form a bond in a DNA molecule is adenine (A) and thymine (T).
In a DNA molecule, the nitrogenous bases form bonds with each other to create the double helix structure. The two types of bonds involved are hydrogen bonds and base-pairing bonds.
Now, let's look at the given options. Thymine and cytosine, guanine and thymine, cytosine and adenine, and adenine and thymine are the pairs of nitrogenous bases.
In DNA, the rule of base-pairing states that adenine (A) always bonds with thymine (T) and cytosine (C) always bonds with guanine (G). This is known as complementary base pairing.
Therefore, the correct pair of nitrogenous bases that will form a bond in a DNA molecule is adenine and thymine.