ap bio unit 1 guide

structure of water and hydrogen bonding

• living systems are organized in a hierarchy of structural levels that interact

• the subcomponents of biological molecules and their sequence determine the properties of that molecule

• living systems depend on properties of water that result from its polarity and hydrogen bonding

• the hydrogen bonds between water molecules result in cohesion, adhesion, and surface tension

elements of life

• the highly complex organization of living systems requires constant input of energy and the exchange of macromolecules

• organisms must exchange matter with the environment to grow, reproduce, and maintain organization

• carbon is used to:

  • build biological molecules such as carbohydrates, proteins, lipids, and nucleic acids

  • it is used in storage compounds and cell formation in all organisms

• nitrogen is used to:

  • build proteins and nucleic acids

• phosphorus is used to:

  • build nucleic acids and certain lipids

intro to biological macromolecules

• living systems are organized in a hierarchy of structural levels that interact

• hydrolysis and dehydration synthesis are used to separate and form covalent bonds between monomers

properties of biological macromolecules

• structure and function of polymers are derived from the way their monomers are assembled:

  • nucleic acids:

    • biological info is encoded in sequences of nucleotide monomers

    • each nucleotide consists of a five-carbon sugar, phosphate group, and nitrogen base

  • proteins:

    • the specific order of amino acids in a polypeptide (primary structure) determines the overall shape of the protein

    • amino acids have directionality, with an amino (NH2) terminus and a carboxyl (COOH) terminus.

    • the R group of an amino acid can be categorized by chemical properties, and the interactions of the R groups determine structure and function of that region of the protein

  • complex carbs:

    • comprise sugar monomers whose structures determine the properties and functions of the molecules

  • lipids:

    • difference in saturation determine the structure and function of lipids

    • phospholipids contain polar regions that interact with other polar molecules, such as water, and nonpolar regions that are often hydrophobic

structure and function of biological macromolecules

• directionality of the subcomponents influences structure and function of the polymer:

  • nucleic acids:

    • have a linear sequence of nucleotides that have ends, defined by the 3’ hydroxyl and 5’ phosphates of the sugar in the nucleotide

    • during DNA and RNA synthesis, nucleotides are added to the 3’ end of the growing strand, resulting in the formation of a covalent bond between nucleotides

    • DNA is structures as an antiparallel double helix, each strand running in opposite 5’ to 3’ orientation

    • A pairs with T, G pairs with C (hydrogen bonds)

  • proteins:

    • comprise linear chains of amino acids, connected by covalent bonds at the carboxyl terminus of the growing peptide chain

  • carbs:

    • comprise of linear chains of sugar monomers connected by covalent bonds

    • polymers may be linear or branched

nucleic acids

• both dna and rna have three components:

  • sugar

  • phosphate group

  • nitrogen base

• the nitrogenous bases are perpendicular to the sugar-phosphate backbone