How do covalent bonds differ from hydrogen bonds? Define base complementarity.

Key Concepts

Covalent Bonds

Covalent bonds are strong chemical bonds formed when two atoms share one or more pairs of electrons. This sharing allows each atom to attain a full outer shell of electrons, leading to greater stability. Covalent bonds are typically found in organic molecules, such as DNA and proteins, and are essential for the structure and function of these biomolecules.

Hydrogen Bonds

Hydrogen bonds are weaker interactions that occur between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom. These bonds are crucial for the properties of water and the structure of biological macromolecules, such as the double helix of DNA, where they help stabilize the strands by forming between complementary base pairs.

Base Complementarity

Base complementarity refers to the specific pairing of nitrogenous bases in nucleic acids, where adenine pairs with thymine (or uracil in RNA) and cytosine pairs with guanine. This principle is fundamental to the structure of DNA, ensuring accurate replication and transcription processes. The hydrogen bonds between complementary bases facilitate the double helix formation and maintain genetic fidelity.