anti-parallel strands
-3′ end of one strand aligns with 5′ end of other-2 strands of DNA run in opposite directions
In DNA, the two strands of the double helix are referred to as anti-parallel because they run in opposite directions. One strand runs in the 5’ to 3’ direction while the complementary strand runs in the 3’ to 5’ direction. This refers to the orientation of the sugar-phosphate backbone of the DNA molecule.
The 5’ end of a DNA strand refers to the carbon atom of the sugar molecule that is attached to a phosphate group. Meanwhile, the 3’ end refers to the carbon atom of the sugar molecule that is attached to a hydroxyl group. The anti-parallel orientation of the two DNA strands allows for complementary base pairing between the nitrogenous bases that make up the middle of the helix – adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C).
This anti-parallel orientation is important for DNA replication and transcription. During DNA replication, enzymes called DNA polymerases add nucleotides to the 3’ end of the growing DNA strand. The anti-parallel nature of the template strand allows for the polymerase to move in the correct direction in order to accurately copy the complementary strand. During transcription, the anti-parallel orientation allows for the formation of RNA molecules that have a complimentary base sequence to the DNA template strand.
Overall, the anti-parallel strands of DNA play a vital role in the stability and functionality of the DNA molecule.
More Answers:
Understanding the Role of DNA Polymerase in DNA Replication and Repair Processes.Understanding the Vital Role of Primase in DNA Replication: Synthesizing RNA Primers for Accurate DNA Synthesis
The Role of Helicase in DNA Replication: Structure, Function, and Importance