Base Pairing

Definition

Base pairing is the fundamental mechanism that allows for the accurate replication and transcription of genetic information in living organisms. It describes the specific interactions between the nitrogenous bases that make up the DNA and RNA molecules, which are essential for maintaining the double-helix structure of DNA and the proper coding of genetic information.

5 Must Know Facts For Your Next Test

1. Base pairing is essential for the accurate replication of DNA during cell division, ensuring that the genetic information is faithfully passed on to new cells.
2. The complementary base pairing of A-T and G-C in DNA, and A-U and G-C in RNA, maintains the double-helix structure and allows for the precise coding of genetic information.
3. During transcription, the base pairing between the DNA template and the complementary RNA nucleotides ensures the accurate synthesis of the mRNA molecule.
4. Disruptions in base pairing, such as mutations, can lead to changes in the genetic code and potentially result in genetic disorders or diseases.
5. The specificity of base pairing is a key feature that allows for the storage and transmission of genetic information in a reliable and efficient manner.

Review Questions

• Explain how base pairing is essential for the replication of DNA during cell division.
  • During DNA replication, the double-helix structure of the DNA molecule unwinds, and each strand serves as a template for the synthesis of a new complementary strand. The specific base pairing rules, where adenine (A) pairs with thymine (T) and guanine (G) pairs with cytosine (C), allow for the accurate copying of the genetic information. This ensures that the genetic material is faithfully replicated and passed on to the daughter cells, maintaining the integrity of the genetic code.
• Describe the role of base pairing in the process of transcription.
  • During transcription, the DNA double helix unwinds, and the enzyme RNA polymerase uses the DNA template to synthesize a complementary RNA molecule (mRNA). The base pairing rules, where adenine (A) pairs with uracil (U) and guanine (G) pairs with cytosine (C), guide the specific incorporation of nucleotides into the growing mRNA strand. This ensures that the genetic information encoded in the DNA is accurately transferred to the mRNA, which can then be used as a template for protein synthesis in the cell.
• Analyze the potential consequences of disruptions in base pairing, such as mutations, and their impact on genetic information and cellular function.
  • Disruptions in base pairing, known as mutations, can lead to changes in the genetic code that may have significant consequences for the organism. These changes can alter the amino acid sequence of the resulting proteins, leading to structural and functional changes that can impair cellular processes or result in genetic disorders. For example, a single base substitution mutation in the hemoglobin gene can cause sickle cell anemia, a genetic condition that affects the shape and function of red blood cells. Understanding the importance of base pairing in maintaining the integrity of the genetic code is crucial for identifying and addressing genetic-based diseases and disorders.

Related terms

Nucleotide: The basic structural unit of DNA and RNA, consisting of a nitrogenous base, a sugar, and a phosphate group.

Complementary Base Pairing: The specific pairing of adenine (A) with thymine (T) in DNA, and adenine (A) with uracil (U) in RNA, due to their ability to form hydrogen bonds.

Watson-Crick Base Pairing: The model proposed by James Watson and Francis Crick that describes the specific pairing of the nitrogenous bases in the DNA double helix structure.