AP BIO

• Elements


  Substances that cannot be broken down into simpler substances by chemical means
• Key elements for building biological molecules


  • Oxygen (O)
  • Carbon (C)
  • Hydrogen (H)
  • Nitrogen (N)
• Trace elements


  • Iron (Fe)
  • Iodine (I)
  • Copper (Cu)
• Other elements are present but in smaller quantities
• Atoms


  The unit of life and the building blocks of the physical world
• Subatomic particles


  • Protons (positively charged)
  • Neutrons (uncharged)
  • Electrons (negatively charged)
• Isotopes


  Atoms with the same number of protons but differ in the number of neutrons in the nucleus
• Compounds


  Consist of two or more elements held together by chemical bonds
• Ionic bond


  Formed between two atoms when one or more electrons are transferred from one atom to the other
• Covalent bond


  Formed when electrons are shared between atoms
• Non-polar covalent bond


  Electrons are shared equally between the atoms
• Polar covalent bond


  Electrons are shared unequally between the atoms
• Hydrogen bond


  Weak chemical bond that forms when a hydrogen atom that is covalently bonded to one molecule is attracted to a highly electronegative atom on another molecule
• Properties of water


  • Cohesion
  • Adhesion
  • Surface tension
  • High heat capacity
  • Expansion on freezing
• Capillary action


  The ability of water to rise up the roots, trunks, and branches of trees due to cohesion and adhesion
• Acidic solution


  Contains a lot of hydrogen ions (H+)
• Basic solution


  Contains a lot of hydroxide ions (OH-)
• pH scale


  Measures the acidity or alkalinity of a solution, numbered from 1 to 14 with 7 being neutral
• pH


  • log [H+], a logarithmic scale representing a tenfold change in hydrogen ion concentration
• Organic molecules


  Molecules with carbon
• Inorganic compounds


  Molecules that do not contain carbon atoms
• Carbon


  • Versatile atom that can bind with other carbons and elements like nitrogen, oxygen, and hydrogen
• Polymers

  Chains of building blocks in macromolecules
• Monomers


  Individual building blocks of a polymer
• Dehydration synthesis


  Process where polymers are formed and a water molecule is lost
• Hydrolysis


  Process where polymers are broken down into monomers and water is added
• Classes of organic compounds central to life


  • Carbohydrates
  • Proteins
  • Lipids
  • Nucleic acids
• Carbohydrates


  Organic compounds containing carbon, hydrogen, and oxygen in a ratio of approximately 1:2:1
• Types of carbohydrates


  • Monosaccharides
  • Disaccharides
  • Polysaccharides
• Monosaccharides


  Simple sugars that are an energy source for cells, e.g. glucose and fructose
• Disaccharides


  Two monosaccharides joined by a glycosidic linkage, e.g. maltose
• Polysaccharides


  Made up of many repeated units of monosaccharides, e.g. starch, cellulose, glycogen
• Starch and glycogen


  • Sugar storage molecules in plants and animals respectively
• Cellulose


  • Made up of β-glucose and is a major part of plant cell walls, providing structural support
• Chitin


  • Polymer of β-glucose molecules, serves as a structural molecule in fungal cell walls and arthropod exoskeletons
• Amino acids


  Building blocks of proteins, containing carbon, hydrogen, oxygen, and nitrogen atoms
• Parts of an amino acid


  • Amino group (-NH2)
  • Carboxyl group (-COOH)
  • Hydrogen
  • R-group (side chain)
• Polarity of side chains


  Affects whether an amino acid is more hydrophobic or more hydrophilic
• Categories of amino acids


  • Hydrophobic (non-polar and uncharged)
  • Hydrophilic (polar and uncharged)
  • Ionic (polar and charged)
• Dipeptide


  Two amino acids joined by a peptide bond