AP Biology

• Elements


  Substances that cannot be broken down into simpler substances by chemical means
• Key elements


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


  Elements required by an organism only in very small quantities
• Examples of trace elements


  • Iron (Fe)
  • Iodine (I)
  • Copper (Cu)
• Atoms


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


  • Protons
  • Neutrons
  • Electrons
• Isotopes


  Atoms with the same number of protons but different numbers of neutrons
• Compounds


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


  • Ionic bonds
  • Covalent bonds
  • Hydrogen 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 atoms
• Elements


  Substances that cannot be broken down into simpler substances by chemical means
• Key elements


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


  Elements required by an organism only in very small quantities
• Examples of trace elements


  • Iron (Fe)
  • Iodine (I)
  • Copper (Cu)
• Atoms


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


  • Protons
  • Neutrons
  • Electrons
• Isotopes


  Atoms with the same number of protons but different numbers of neutrons
• Compounds


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


  • Ionic bonds
  • Covalent bonds
  • Hydrogen 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 atoms
• Polar covalent bond


  Electrons are shared unequally between atoms
• Hydrogen bond


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


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


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


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


  Numbered from 1 to 14, with 7 being neutral
• pH


  • log [H+]
• 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 by which polymers are formed, where a water molecule is lost
• Hydrolysis


  Process by which polymers are broken down into monomers, where water breaks the bond between two monomers
• 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