Humans have two strands of DNA. These strands form the famous double helix structure, which was discovered by James Watson and Francis Crick in 1953. Each strand is made up of a long chain of nucleotides, and the two strands are held together by hydrogen bonds between complementary bases: adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G).
This double-stranded structure is crucial for DNA replication and the transmission of genetic information. During cell division, the two strands separate, and each serves as a template for the creation of a new complementary strand, ensuring that each new cell receives an exact copy of the DNA.