Nucleic acids

• 2% of body weight

• storage

• expression

• expression of genetic information

• DNA

• RNA

• subunit - nucleotide

Nucleic acids

• Heterocyclic compounds - purine/pyrimidine

• sugar

• phosphate group - ester bond to 5 carbon, bind to 3 carbon

• ends with ylate

• written from 5 prime to 3 prime

Nucleotides

• 1 ring stucture

• labelled in numbers - nitrogen attached to sugar is the 1st one

• thymine

• cytosine

• uracil

pyrimidine

• double ring structure

• labelled in numbers - nitrogen attached to sugar always last one

• adenine

• guanine

purine

• atoms in the sugar of a nucleoside or nucleotide - labelled with an apostrophe (prime)

• able to distinguish them from the atoms in the nucleic acid base

• DNA - D-2 Deoxyribose

• RNA - D-ribose

sugar

• adding a sugar and a nitrogenous base

• -side ending

Nucleosides

• double helix

• anti-parallel fashion

• 1 strand of DNA from 5 to 3 prime and other strand 3-5 prime

• one purine forms H-bonds with one pyrimidine base

• complementary strands

• hydrophobic interactions between base pairs

• non covalent forces of attraction between aromatic rings

• sugar phosphate backbone interacts with water

DNA

• DNA converted to RNA

• Reverse transcription - RNA to DNA

Transcription

RNA to protein

Translation

• links together to form a polymer - genetic code

• caffeine (similar to adenosine) - signalling

• energy storage and transfer - ATP and GTP

• Cyclic nucleotides - secondary messengers (cAMP)

• Components of coenzymes - metabolism (coA, NAD+)

• Intermediates and cofactors in several anabolic pathways (UDP glucose)

• allosteric effectors

Functions of nucleotides

• complete breakdown

• nucleic acids - nucleotides - nucleosides - purine and pyrmidine

• active base absorption

Absorption of nucleic acids

• 15%

• transfer a linked amino acid atatched to the 3 hydroxyl end of the molecule to the polymerisation process of a protein synthesis

• tRNA

• unique to every amino acid

• link to cytoplasmic ribosome for translation

• codon region intracts with mrna generate sequence of aa for protein synthesis

transfer RNA

• 2-5 %

• contains message code from the nucleus that is used to create the strands of amino acids in a specific order within the translation machinery in the cytoplasm

messenger mRNA

• 80%

• ribosomal

• major component of ribosomes - make up the machinery where the mRNA and tRNA come together in a controlled environment to allow the generation of the protein sequence

rRNA

• assists with the splicing of mRNA within the nucleus

• snRNA

• less than 1%

Small nuclear of sRNA

• non coding RNA that helps to control the rate of message conversion to protein in cytoplasm

• miRNA

• less than 1%

micro RNA

• mammalian ribosomes - large and small subunit

• measured in Sveberg unit - S

• Large subunit = 60S 3 rRNA and 50 polypeptides

• Small sub unit 40S - 18S rRNA and 30 polypeptides

rRNA with ribosomes

• protien synthesis is intitated when an mRNA, ribosome and first tRNA molecule come together

Translation

• adenosine triphosphate

• energy transfer source

• ATP broken down into ADP + P + hydrogen ions and energy

• used for synthesis of organic molecules, active transport and movement

• used very quickly - needs to be replaced quickly

• ADP to ATP - by glycolysis

ATP