AP BIO

• Water might be the most amazing molecule on Earth and it can defy gravity
• Water molecule


  Two elements of hydrogen for every element of oxygen form with polar covalent bonds
• Water molecule


  • Oxygen has a partial negative charge while each hydrogen atom has a partial positive charge
  • This uneven distribution of charge results in a polar molecule
• Hydrogen bonding


  Forms between a partial positive hydrogen of one water molecule and a partial negative oxygen of another water molecule
• Properties of water


  • Adhesion
  • Cohesion
  • Surface tension
• Water movement in plants

  1. Adhesion to plant vasculature walls

  2. Cohesion between water molecules

  3. Transpiration at leaves creates a pulling force
• Matter is made up of atoms, has mass and takes up space
• Energy is not made up of atoms
• Atoms


  Contain protons, neutrons and electrons
• Metabolism


  The sum of all chemical reactions that take place within an organism, including bond-breaking catabolic reactions and bond-forming anabolic reactions
• Organic molecules


  Contain carbon, which forms four covalent bonds
• Six most common elements in living things

  • Carbon
  • Hydrogen
  • Nitrogen
  • Oxygen
  • Phosphorus
  • Sulfur
• Dehydration reaction


  Used to join monomers together and form a larger polymer, by removing water
• Hydrolysis reaction


  Adds water to break a polymer into monomers
• Amino acid


  Made up of one central carbon atom that forms four single covalent bonds, including to an acidic carboxyl group and a basic amino group, and a unique R group side chain
• Protein synthesis


  1. Amino acids link together through dehydration synthesis to form a polypeptide chain

  2. The polypeptide chain undergoes further processing in the ER and Golgi body
• Protein structure


  • Primary (amino acid sequence)
  • Secondary (alpha helix or beta sheet)
  • Tertiary (3D shape)
  • Quaternary (multiple polypeptide chains)
• Protein denaturation


  Disruption of hydrogen bonds that maintain protein structure, affecting function
• Functions of proteins


  • Cellular membranes
  • Transport
  • Recognition
  • Movement
  • Communication
• Tertiary structure


  Specific 3D shape when alpha helices and beta sheets fold further inwards due to hydrogen bonding interactions
• Quaternary structure


  Two or more separate amino acid chains interacting and bonding together
• Protein structure


  Dependent upon the chemical properties of the R Group and can be influenced by environmental factors
• Hydrophilic/charged R groups


  Fold outward toward the aqueous environment
• Hydrophobic R groups


  Face the interior of the protein
• Protein denaturation


  Hydrogen bonds are disrupted, causing a change in shape that affects function, can sometimes be reversed
• Roles of proteins in cells

  • Key component in cellular membranes
  • Transport
  • Recognition
  • Movement
  • Communication
• Integral membrane proteins


  Have hydrophobic regions that interact with phospholipid tails and hydrophilic regions adjacent to heads
• Integral membrane proteins with channels

  Have specific molecular chemistry internally forming a channel that may be gated and allow specific ions or small molecules to cross the membrane through facilitated diffusion or active transport
• Peripheral proteins


  More loosely attached to the membrane, involved in cell recognition and communication
• Membrane proteins


  Can provide anchorage for the cytoskeleton, aiding in structural support and cellular movement
• Enzymes


  Catalyze chemical reactions for specific substrates, have a specific active site that fits the substrate
• Carbohydrates


  Contain carbon, hydrogen and oxygen in a 1:2:1 ratio, formed from monosaccharide monomers joined by glycosidic bonds
• Monosaccharides


  Glucose, fructose, galactose
• Disaccharides


  Lactose, sucrose
• Polysaccharides


  Cellulose, chitin, starch, glycogen
• Carbohydrate functions


  Primary source of chemical energy, structural material
• Glucose


  C6H12O6, used in cellular respiration and photosynthesis
• Lipids


  Hydrophobic molecules with a H:O ratio greater than 2:1, include fats, phospholipids, steroids
• Fats


  Contain glycerol and long hydrocarbon fatty acid chains
• Saturated fatty acids


  Hydrocarbon chains with all single bonds, straight and closely packed