Unlock the Secrets of DNA & Biotech 2026 – Dive into the Future of Science!

In DNA, bases pair through specific hydrogen bonding and shape fit to keep the double helix uniform. Cytosine pairs with guanine because a pyrimidine (cytosine) matches best with a purine (guanine), allowing three hydrogen bonds to form between them. This makes the C–G pair stable and helps maintain the helix width. Thymine pairs with adenine (two hydrogen bonds), and cytosine does not pair with thymine or adenine in standard Watson–Crick pairing. So the partner for cytosine is guanine.