Question

What linkage joins the monomers in each strand of DNA?

Short answer

Phosphodiester bond joins the monomers in each strand of DNA.

Step-by-step solution

Understand the Structure of DNA

DNA (deoxyribonucleic acid) is composed of two long strands of nucleotides that form a double helix structure. Each nucleotide consists of a sugar molecule, a phosphate group, and a nitrogenous base.

Identify the Monomers

The monomers of DNA are nucleotides. Each nucleotide is composed of three parts: a deoxyribose sugar, a phosphate group, and a nitrogenous base.

Determine the Linkage Between Nucleotides

The linkage that joins the nucleotides in each strand of DNA is a phosphodiester bond. This bond is formed between the phosphate group of one nucleotide and the hydroxyl group of the sugar molecule of the next nucleotide.

Describe the Formation of the Phosphodiester Bond

A phosphodiester bond is created through a dehydration reaction, where a water molecule is removed to link the phosphate group of one nucleotide to the 3' hydroxyl group of another nucleotide's deoxyribose sugar.

Key concepts

DNA structure

DNA, or deoxyribonucleic acid, is the molecule that carries the genetic instructions for life. It is composed of two long strands of repeating units called nucleotides. These strands twist together to form a double helix. The structure is like a ladder, with the sugar and phosphate molecules forming the sides and the nitrogenous bases forming the rungs. Each strand runs in opposite directions, a feature known as antiparallel. The order of these base pairs holds the genetic information needed for development and function.

Nucleotide

A nucleotide is the basic building block of DNA. Each nucleotide has three components: a deoxyribose sugar, a phosphate group, and a nitrogenous base. There are four types of nitrogenous bases in DNA: adenine (A), thymine (T), cytosine (C), and guanine (G). These bases pair up in a specific way: A always pairs with T, and C always pairs with G. This pairing is crucial for the accurate copying of DNA during cell division and inheritance. The sequence of nucleotides forms genes, which encode the instructions for making proteins.

Phosphodiester bond

The phosphodiester bond is the chemical link between the sugar of one nucleotide and the phosphate group of the next. This bond forms the backbone of the DNA strand. It connects the 3' carbon atom of the sugar in one nucleotide to the 5' carbon atom of the sugar in the next nucleotide. This linkage provides structural stability and allows the DNA to be flexible and compact. These bonds are strong, ensuring the DNA strand remains intact even under various conditions.

Dehydration reaction

A dehydration reaction is a chemical reaction that involves the loss of a water molecule when forming a new bond. In DNA, this process helps create the phosphodiester bonds between nucleotides. When the 3' hydroxyl group of one nucleotide reacts with the phosphate group of another, a water molecule is released, and a phosphodiester bond is formed. This reaction is enzymatically catalyzed during DNA replication and repair, facilitating the linking of nucleotides into a continuous strand.

Deoxyribose sugar

The deoxyribose sugar is a five-carbon sugar molecule that is an essential part of the DNA structure. It differs from ribose (found in RNA) by having one less oxygen atom. Each deoxyribose sugar molecule connects to a phosphate group and a nitrogenous base. In the DNA double helix, the deoxyribose sugars, along with phosphate groups, make up the backbone of each DNA strand. The 3' and 5' carbon atoms of deoxyribose are key to forming phosphodiester bonds, linking nucleotides together.