Question

How is genetic information encoded in a DNA molecule?

Short answer

Question: Explain how DNA encodes genetic information through the use of nucleotides and base pairing. Answer: DNA encodes genetic information through the specific sequence of nucleotides, each containing a unique nitrogenous base (adenine, guanine, cytosine, or thymine). The base pairing rules (A-T and G-C) ensure accurate replication and storage of genetic information by forming complementary hydrogen bonds between the double helix strands. The genetic code within the DNA molecule determines the sequence of amino acids during protein synthesis, with each set of three nucleotides (codon) representing a specific amino acid.

Step-by-step solution

Understand the basic structure of DNA

Deoxyribonucleic acid (DNA) is a double helix structure consisting of two long chains (polynucleotides) of nucleotides. Each nucleotide is composed of three components: a sugar molecule (deoxyribose), a phosphate group, and a nitrogenous base. The sugar and phosphate groups form the backbone of the DNA molecule, while the nitrogenous bases are responsible for storing genetic information.

Learn about the four types of nucleotides

There are four different types of nucleotides, each with its specific nitrogenous base: adenine (A), guanine (G), cytosine (C), and thymine (T). The unique structure of each base allows them to only form hydrogen bonds with a specific complementary base on the opposite DNA strand, creating a well-defined pattern called base pairing rules.

Understand base pairing rules

In DNA, adenine (A) forms hydrogen bonds with thymine (T), and guanine (G) forms hydrogen bonds with cytosine (C). This is known as complementary base pairing: A-T and G-C. The base pairing rules ensure that the DNA double helix has a consistent structure and that genetic information can be stored and replicated accurately.

Comprehend how genetic information is encoded in DNA

Genetic information is encoded in the sequence of nucleotides (nitrogenous bases) within the DNA molecule. The order of these bases determines the genetic code, which in turn dictates the sequence of amino acids during protein synthesis. Each set of three nucleotides, called a codon, represents a specific amino acid. For example, the codon ATG codes for the amino acid methionine while the codon CGC codes for the amino acid arginine.

Recap the encoding process

In summary, genetic information is encoded in a DNA molecule through the specific sequence of nucleotides and their corresponding nitrogenous bases. The base pairing rules ensure accurate replication and storage of this genetic information, while the genetic code determines the amino acid sequence for protein synthesis.