3.1. DNA: Structure and Function

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DNA: Structure and function

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The DNA molecule is made of nucleotides

Nucleotides consist of a sugar rest (S) with phosphate (P) and a nucleobase. There are four nucleobases present in DNA: Cytosine (C), guanine (G), thymine (T) and adenine (A).

The nucleotides present in DNA.The nucleotides present in DNA. In DNA, A always base pairs with T, and C always base pairs with G (and vice versa).In DNA, A always base pairs with T, and C always base pairs with G (and vice versa).

The DNA molecule is packed around histone proteins. During mitosis (cell division), large X-like structures are formed: mitotic chromosomes.The DNA molecule is packed around histone proteins. During mitosis (cell division), large X-like structures are formed: mitotic chromosomes.

The DNA molecule's two functions

First: DNA contains genetic information – "recipes" for proteins. 

A gene codes for a protein.A gene codes for a protein.

Second: By replicating, the DNA carries the genetic information to the next generation.

The two functions of the DNA molecule are often called "the central dogma of molecular biology".

The central dogma of molecular biology summarized.The central dogma of molecular biology summarized.