Answer:
adenine pairs with Thymine and guanine always pairs with cytosine respectively
Explanation:
In DNA nucleotide subunits, there are four nitrogenous bases:
- Adenine (A)
- Thymine (T)
- Cytosine (C)
- Guanine (G)
Each of these bases can be divided into two categories: purine bases and pyrimidine bases.
Adenine and guanine are examples of purine bases. This means their structure is a nitrogen-containing six atom ring joined with a nitrogen-containing five atom ring that share two atoms to combine the two rings.
Thymine and cytosine are examples of pyrimidine bases.
Note that RNA replaces thymine with a different pyrimidine base called uracil (U).
The complementary base pairing rule, Chargaff's rule states that DNA base pairs are always adenine with thymine (A-T) and cytosine with guanine (C-G). A purine always pairs with a pyrimidine and vice versa. However, A doesn't pair with C, despite that being a purine and a pyrimidine.
