Understanding Antiparallel DNA Strands: Importance of Opposing Directions in DNA Structure

What is meant by the description “antiparallel” regarding the two strands that make up the DNA double helix?A) The double helix structure of DNA creates nonparallel strands.B) The 5′ to 3′ direction of one strand runs counter to the 5′ to 3′ direction of the other strand. C) Base pairings create unequal spacing between the two DNA strands.D) One strand contains only purines and the other contains only pyrimidines.

The correct answer is B) The 5′ to 3′ direction of one strand runs counter to the 5′ to 3′ direction of the other strand

The correct answer is B) The 5′ to 3′ direction of one strand runs counter to the 5′ to 3′ direction of the other strand.

In the DNA double helix structure, the two strands are oriented 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 what is meant by “antiparallel.” In a DNA molecule, the carbon atoms in the sugar component of the nucleotides are numbered, and the 5′ end refers to the end where the phosphate group is attached to the 5th carbon atom, while the 3′ end refers to the end where the hydroxyl group is attached to the 3rd carbon atom.

The antiparallel nature of the DNA strands is important because it allows for the complementary base pairing between the nucleotides. Adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G) through hydrogen bonds. The complementary base pairing ensures that the genetic information is accurately copied during DNA replication and allows for the precise alignment of the nucleotides during protein synthesis.

So, “antiparallel” describes the opposite directionality of the two DNA strands, with one running from the 5′ to 3′ end and the other running from the 3′ to 5′ end.

More Answers: