Unit 2) 8.1 Structure of DNA

Structure of DNA

DNA is the chemical that determines inherited characteristics and it contains vast amounts of information in the form of genetic code.

Nucleotide Structure

A nucleotide (monomer) is made up of 3 basic components:

• deoxyribose sugar
• a phosphate group
• organic base, belonging to 1 of 2 groups
  • single ring bases- cytosine (C) and thymine (T)
  • double ring bases- adenine (A) and guanine (G)

These 3 basic components are compined through condensation reactions; this creates a single nucleotide (mononucleotide)

2 mononnucleotides may be combined as a result of a condensation reaction between the deoxyribose sugar of 1 and the phosphate of the other. This creaates a dinucleotide.

Repeated condesation reactions like this forms a long chain of mononucleotides known as a polynucleotide.

DNA Structure

The DNA structure was worked out by Francis Crick and James Watson in 1953, who were followig the work of Rosalind Franklin on the X-ray diffraction patterns of DNA.

DNA is made up…