chapter 7

Cards (27)

  • Proteins
    One of the most abundant organic molecules in living systems with the most diverse range of functions of all macromolecules
  • Functions of proteins
    • Structural
    • Regulatory
    • Contractile
    • Protective
    • Transport
    • Storage
    • Membrane
    • Toxins
    • Enzymes
  • Each cell in a living system may contain thousands of different proteins, each with a unique function
  • Amino acids
    The monomers that make up proteins
  • There are 20 different chemically distinct amino acids that form long chains, and the amino acids can be in any order
  • Enzymes
    Catalysts in biochemical reactions (like digestion) that are usually proteins, each specific for the substrate upon which it acts
  • Hormones
    Chemical signaling molecules, usually proteins or steroids, secreted by an endocrine gland or group of endocrine cells that act to control or regulate specific physiological processes
  • Protein shape
    • Critical to its function
    • Changes in temperature, pH, and exposure to chemicals may lead to permanent changes in the shape of the protein, leading to a loss of function or denaturation
  • All proteins are made up of different arrangements of the same 20 kinds of amino acids
  • Amino acid
    The monomers that make up proteins, each with a central carbon atom bonded to an amino group, a carboxyl group, and a variable R group
  • Peptide bond
    The covalent bond formed between the carboxyl group of one amino acid and the amino group of a second amino acid, releasing a water molecule
  • Polypeptide
    A polymer of amino acids
  • Protein
    A polypeptide or polypeptides that have combined together, have a distinct shape, and have a unique function
  • The sequence and number of amino acids ultimately determine a protein's shape, size, and function
  • Cytochrome c is an important component of the molecular machinery that harvests energy from glucose, and has changed very little over millions of years
  • Protein sequencing has shown that there is a considerable amount of sequence similarity among cytochrome c molecules of different species, allowing evolutionary relationships to be assessed
  • In sickle cell anemia, the hemoglobin β chain has a single amino acid substitution, causing a change in both the structure and function of the protein
  • Primary structure

    The unique sequence and number of amino acids in a polypeptide chain
  • Secondary structure
    Folding patterns resulting from interactions between the non-R group portions of amino acids, including alpha-helix and beta-pleated sheet structures
  • Tertiary structure
    The unique three-dimensional structure of a polypeptide, caused by chemical interactions between various amino acids and regions of the polypeptide
  • Quaternary structure
    The interaction of multiple polypeptide subunits to form a complete protein
  • Denaturation is the loss of a protein's shape, often reversible if the denaturing agent is removed, but sometimes irreversible
  • Nucleic acids are key macromolecules in the continuity of life, carrying the genetic blueprint and instructions for cell functioning
  • DNA
    The genetic material found in all living organisms, ranging from single-celled bacteria to multicellular mammals
  • RNA
    Mostly involved in protein synthesis, communicating genetic information from the nucleus to the rest of the cell
  • Nucleotide
    The monomers that make up DNA and RNA, consisting of a nitrogenous base, a pentose sugar, and a phosphate group
  • DNA has a double-helical structure composed of two strands of nucleotides bonded at the bases with hydrogen bonds