Complementary base pairs

Definition

Complementary base pairs are specific pairs of nitrogenous bases in DNA that bond together through hydrogen bonds, following the base pairing rules. In DNA, adenine (A) pairs with thymine (T), while cytosine (C) pairs with guanine (G). This pairing is crucial for the accurate replication of DNA, ensuring that genetic information is preserved and passed on during cell division.

5 Must Know Facts For Your Next Test

1. Complementary base pairing is essential for maintaining the structure of the DNA double helix, as it stabilizes the molecule.
2. During DNA replication, complementary base pairs ensure that each new DNA strand is an exact copy of the original strand, which is critical for genetic fidelity.
3. Errors in base pairing can lead to mutations, which may affect protein synthesis and cellular function.
4. The specific pairing of bases allows for the encoding of genetic information in a precise sequence, facilitating heredity and evolution.
5. In prokaryotes, complementary base pairing occurs in a bidirectional manner during replication, with two replication forks moving away from a single origin of replication.

Review Questions

• How do complementary base pairs contribute to the accuracy of DNA replication?
  • Complementary base pairs are vital for ensuring that DNA replication occurs accurately. Each nucleotide added to a growing DNA strand is matched with its complementary base on the template strand, following specific pairing rules. This precise matching minimizes errors during replication and helps maintain the integrity of genetic information as it is passed from one generation to the next.
• What role does DNA polymerase play in the context of complementary base pairing during replication?
  • DNA polymerase is crucial for synthesizing new strands of DNA by adding nucleotides that are complementary to the template strand. It recognizes the existing bases on the template and ensures that only the correct complementary nucleotides are added to form a new strand. This enzyme's activity is essential for creating accurate copies of DNA during replication, which relies on complementary base pairing.
• Evaluate the consequences of errors in complementary base pairing during DNA replication and their potential impact on an organism.
  • Errors in complementary base pairing can lead to mutations, which may disrupt normal gene function and protein synthesis. These mutations can result in various outcomes, ranging from benign variations to serious genetic disorders or increased susceptibility to diseases like cancer. Furthermore, if these errors occur in germ cells, they can be passed on to future generations, potentially affecting population genetics and evolution over time.

Related terms

DNA polymerase:

An enzyme that synthesizes new DNA strands by adding nucleotides complementary to the template strand during DNA replication.

Helicase: An enzyme that unwinds the DNA double helix at the replication fork, allowing the two strands to separate and serve as templates for replication.

Replication fork: The Y-shaped region where the DNA double helix is separated into two single strands for replication to occur.