Final answer:
The secondary structure of DNA consists of a double helix with antiparallel strands, complementary base pairing, and base stacking. The double helix is formed by two strands twisted together, held by hydrogen bonds between bases. The nucleotide bases in DNA pair in a specific way: A with T, and C with G.
Step-by-step explanation:
The secondary structure of DNA refers to the arrangement of the nucleotide bases along the DNA molecule. There are four main features of the secondary structure of DNA:
- Double helix: DNA is composed of two strands that are twisted together in a spiral shape, forming a double helix structure. The two strands are held together by hydrogen bonds between complementary nucleotide bases.
- Antiparallel strands: The two strands of DNA run in opposite directions, with one strand running in the 5' to 3' direction and the other running in the 3' to 5' direction. This is known as antiparallel orientation.
- Complementary base pairing: The nucleotide bases in DNA, adenine (A), thymine (T), cytosine (C), and guanine (G), pair together in a specific way: A pairs with T, and C pairs with G. This is known as complementary base pairing.
- Base stacking: The nucleotide bases in each strand of DNA are stacked on top of each other, forming a stable and compact structure. Base stacking interactions help stabilize the double helix structure.