Midterms 3

• Nucleic acids


  Serve as genetic material of all living organisms, including humans. Involved in the storage, transfer, and expression of genetic information needed by our cells. Contains all the necessary information required for the formation of the individual or a certain organism.
• Types of nucleic acids

  • DNA (Deoxyribonucleic acid)
  • RNA (Ribonucleic acid)
• Nucleic acids


  Found in nucleus and are acidic in nature. Contain Nitrogen or Nitrogenous Bases, Sugar, and Phosphorus. A nucleic acid is a polymer in which the monomer units are nucleotides.
• Nucleotides

  Building blocks of nucleic acids. More complex than the monosaccharides of polysaccharides. Have three components: Pentose Sugar, Phosphate Group, and Heterocyclic Base.
• DNA


  • Found within cell nucleus and mitochondria. Storage and responsible in transfer of genetic information. Passed from one cell to other during cell division.
• RNA


  • Occurs in all parts of cell. Present in nucleus and cytoplasm. Primary function is to synthesize the proteins.
• Pentose sugar


  Ribose is present in RNA and 2-deoxyribose is present in DNA. Nucleotides are named according to the type of sugar present.
• Nitrogen-containing heterocyclic bases

  Pyrimidine bases (Thymine, Cytosine, Uracil) and Purine bases (Adenine, Guanine). Both are bases because they contain amine functional groups.
• Phosphate group


  Derived from phosphoric acid (H3PO4). Under cellular pH conditions, the phosphoric acid is fully dissociated to give a hydrogen phosphate ion (HPO42-).
• Nucleoside


  A two sub-unit molecule in which a pentose sugar is bonded to a nitrogen-containing heterocyclic base.
• Nucleotide

  Formed by the addition of a phosphate group to a nucleoside. Has three structural components: Nitrogenous bases, sugar, and phosphate.
• Nucleotide nomenclature


  Nucleotides are named by appending the term 5-monophosphate or 5 prime monophosphates to the name of the nucleoside wherein they are derived.
• Primary structure of nucleic acids

  • Sequence of nucleotides in DNA or RNA. Confers individuality to the polynucleotide chain. Has a direction represented by 5' to 3'.
• DNA double helix

  • Two polynucleotide chains coiled around each other in a helical fashion. Strands run anti-parallel (opposite directions) to each other. Bases are located at the center and hydrogen bonded (A=T and G triple bonded with C). Base composition must be equal (%A=%T and %C=%G).
• Types of RNA molecules

  • Heterogenous nuclear RNA (hnRNA)
  • Messenger RNA (mRNA)
  • Small nuclear RNA
  • Ribosomal RNA (rRNA)
  • Transfer RNA (tRNA)