2.1.3 nucleotides and nucleic acids

    Cards (98)

    • in eukaryotic cells DNA is found in the nucleus
    • chromatin is made up of DNA and histone proteins
    • DNA stands for deoxyribonucleic acid and acts as an information store
    • RNA stands for ribonucleic acid and has three different forms mRNA, rRNA and tRNA
    • RNA is needed to translate the code from DNA to make proteins
    • a nucleotide is made up of an inorganic phosphate group, a pentose sugar and a nitrogen containing base
    • the pentose sugar in DNA is deoxyribose
    • the pentose sugar in RNA is ribose
    • the difference in structure of ribose and deoxyribose is that deoxyribose doesn’t have a hydroxyl group below carbon 2 only a hydrogen
    • individual bases are joined together by a condensation reaction to form a phosphodiester bond
    • there are five types of nitrogen-containing bases adenine (A), guanine (G), thymine (T), uracil (U) and cytosine (C)
    • adenine and guanine are purine bases as they have 2 rings
    • thymine, cytosine and uracil are pyrimidine bases as they only contain one ring
    • guanine is found in DNA and RNA
    • thymine is only found in DNA
    • cytosine is found in both DNA and RNA
    • uracil is only found in RNA as it replaces thymine
    • when forming a nucleotide like adenosine monophosphate two water molecules are produced
    • adenosine is formed when adenine are ribose are joined
    • ATP stands for adenosine triphosphate
    • ADP stands for adenosine diphosphate
    • ATP and ADP are phosphorylated nucleotides
    • nucleotides are joined together to form polynucleotides by condensation reactions
    • phosphodiester bonds join nucleotides together
    • phosphodiester bonds form when the phosphate group at the 5th carbon of the pentose sugar on one nucleotide forms a covalent bond with the hydroxyl group at the 3rd carbon of pentose sugar of an adjacent nucleotide
    • phosphodiester bonds can be broken by a hydrolysis reaction
    • the 2 strands that make up DNA are antiparallel to each other as one runs from 5’ to 3’ and the other runs from 3’ to 5’
    • 3’ is the end which is closest to carbon 3 in ribose
    • 5’ is the end which is closest to carbon 5 on ribose
    • antiparallel is when one strand runs the other way around to the second strand
    • the four bases in DNA are A,T,G,C
    • adenine binds with thymine
    • guanine binds with cytosine
    • specific base pairing is the fact that A and T always bind together and so do G and C.
    • one purine base bonds to one pyrimidine base.
    • a hydrogen bond is a weak bond within or between molecules and result from an interaction of polar covalent bonds
    • between G and C there are 3 hydrogen bonds
    • between A and T there are 2 hydrogen bonds
    • the phosphate group in DNA is acidic and the nitrogenous base is alkaline
    • in solution the phosphate groups easily loses a H to become negatively charged, this is why DNA carries a large charge, the loses of a H /proton makes DNA an acid