DNA structure and Replication

nucleic acid

A nucleic acid is a biopolymer made up of nucleotide monomers, which are essential for storing and expressing genetic information.

nucleotide

A nucleotide is the basic building block of nucleic acids, consisting of a nitrogenous base, a five-carbon sugar, and one or more phosphate groups.

double helix

The structure of DNA, consisting of two intertwined strands forming a spiral, held together by hydrogen bonds.

Chargaff’s rule

The principle that in a DNA molecule, the number of adenine bases equals the number of thymine bases, and the number of cytosine bases equals the number of guanine bases.

Watson & Crick

The scientists who proposed the double helical structure of DNA in 1953, based on X-ray diffraction data from Rosalind Franklin.

Rosalind Franklin

A chemist and X-ray crystallographer who contributed to the discovery of the DNA double helix structure through her X-ray diffraction images of DNA.

Nitrogenous base

A molecule that contains nitrogen and acts as a building block of DNA and RNA, including adenine, thymine, cytosine, and guanine.

phosphate group

A molecular structure consisting of a phosphorus atom bonded to four oxygen atoms, linking the sugar backbone of nucleotides.

deoxyribose

A sugar molecule that forms part of the backbone of DNA

semi-conservative replication

The method of DNA replication where each new DNA molecule consists of one original strand and one newly synthesized strand. This process ensures genetic continuity.

helicase

An enzyme that unwinds the DNA double helix by breaking hydrogen bonds between the bases during DNA replication.

DNA polymerase

An enzyme responsible for synthesizing new DNA strands by adding nucleotides complementary to the template strand during DNA replication.

ligase

An enzyme that facilitates the joining of DNA fragments by sealing nicks in the DNA backbone during replication and repair.

DNA function

code to build proteins

gene

a segment of DNA that contains the instructions for making a specific protein