Describe the structure of a DNA molecule: (a) two strands coiled together to form a double helix (b) each strand contains chemicals called bases (c) bonds between pairs of bases hold the strands together (d) the bases always pair up in the same way: A with T, and C with G (full names are not required)

The structure of a DNA molecule can be described as follows:

(a) Two Strands Coiled Together to Form a Double Helix

• DNA consists of two long strands that are coiled around each other, forming a structure known as a double helix. This helical shape resembles a twisted ladder, with the two strands running in opposite directions (antiparallel).

(b) Each Strand Contains Chemicals Called Bases

• Each strand of DNA is composed of a backbone made of sugar and phosphate groups, with bases attached to the sugar molecules. These bases are the key components that carry genetic information.

(c) Bonds Between Pairs of Bases Hold the Strands Together

• The two strands of the double helix are held together by hydrogen bonds formed between pairs of bases on opposite strands. These bonds provide stability to the DNA structure while allowing for the strands to separate during processes such as replication and transcription.

(d) The Bases Always Pair Up in the Same Way: A with T, and C with G

• The bases pair specifically according to complementary base pairing rules: A (adenine) pairs with T (thymine), and C (cytosine) pairs with G (guanine). This specific pairing is crucial for maintaining the integrity of the genetic code during DNA replication and ensuring accurate transmission of genetic information.