Nucleotides and Nucleic Acids

Nucleotides - make nucleic acids
A type of biological molecule
Made from pentose sugar (sugar with 5 carbon atom or deoxyribose), nitrogenous base +
phosphate group

All nucleotides contain Hydrogen, Oxygen, Nitrogen, Carbon,
Phosphorus
Important as they are monomers that make up DNA/RNA (nucleic
acids)
DNA = store genetic information RNA = make proteins from
instructions in DNA
4 possible bases = Adenine, Thymine, Guanine, Cytosine
Adenine and guanine = purine bases = 2 carbon-nitrogen ring (bigger)
Thymine and Cytosine = pyrimidine bases = 1 carbon-nitrogen ring (smaller)

In a DNA molecule - 2
polynucleotide chains
In RNA, uracil replaces thymine
as a base
Made up of a single
polynucleotide chain

ADP + ATP = Phosphorylated nucleotides

To phosphorylate a nucleotide, add one or more phosphate groups
ADP = adenine base, ribose sugar, 2 phosphate groups
ATP = adenine base, ribose sugar, 3 phosphate groups

ATP provides energy for chemical reactions in cells
ATP synthesised from ADP + inorganic phosphate using the energy from an
energy-releasing reaction
ADP phosphorylated to form ATP + phosphate group formed
Energy stored in phosphate group - when energy is needed, ATP is broken back down
into ADP + inorganic phosphate

Nucleotides join together = polynucleotides
Nucleotides join up between phosphate group of one nucleotide + sugar of another - forms
phosphodiester bond (consists of a phosphate group + 2 ester bonds)

Chains of sugars and phosphates = sugar-phosphate backbone