Nucleic Acids

• A nucleotide is a monomer of nucleic acids
• DNA and RNA are examples of nucleic acids made of nucleotides
• A nucleotide has three components which are a phosphate group, a pentose sugar and an organic base.
• Pyrimidines have a single ring structure.
• Purines have a double ring structure.
• Thymine, cytosine and uracil are examples are pyrimidines.
• Adenine and guanine are examples of purines.
• ATP is a nucleotide.
• ATP is a molecule that makes energy available when it is needed.
• ATP is known as the ’universal energy currency’.
• ATP stands for adenosine triphosphate.
• ATP is made from ADP and inorganic phosphate.
• Energy is needed to make ATP so this is described as an endergonic reaction.
• Energy can be released when ATP is hydrolysed to make ADP and inorganic phosphate.
• Energy is released during the hydrolysis of ATP so this is an exergonic reaction.
• A phosphodiester bond is a bond between the phosphate group of one nucleotide and the sugar of the next.
• Thymine pairs with adenine.
• Cytosine pairs with guanine.
• Adenine pairs with uracil in RNA.
• DNA is a stable molecule so it does not fall apart so the genetic code isn’t lost.
• DNA has a large number of hydrogen bonds.
• DNA has two strands with specific base pairing.
• The double helix structure of DNA means that the hydrogen bonds are on the inside of the molecule, is therefore protected and there is less chance of damage.
• DNA has a strong sugar-phosphate backbone.
• RNA is ribonucleic acid.
• The bases in RNA can be cytosine, guanine, adenine and uracil.
• DNA helicase is an enzyme which unwinds DNA.
• RNA polymerase breakers hydrogen bonds between bases, bring in RNA nucleotides to complement the DNA template strand, attach RNA nucleotides with phosphodiester bonds.
• Three bases in the DNA coding strand is a triplet code.
• Three bases on mRNA is called a codon.
• The genetic code is non-overlapping which means each base appears in only one triplet.
• The genetic code is degenerate which means it has more than one way of coding for the same amino acid.
• The genetic code is a triplet codes which means bases are arranged in sets of three.
• The genetic code is universal which means all living things have the same code.
• The genetic code is punctuated which means it has start and stop signals.
• Transcription is the process in which the genetic information contained in a DNA molecule is copied to produce messenger RNA.
• Translation is the process which takes place on a ribosome where amino acids are joined to form a polypeptide.
• A triplet code is the information on DNA is carried by sequences of three neighbouring bases.
• A codon is a sequence of three nucleotide bases on a messenger RNA molecule that codes for a particular amino acid.
• An anti-codon is a sequence of three nucleotide bases on a transfer RNA molecule which is complementary to the corresponding messenger RNA codon.