AP Bio Unit 1

• Ionic bonds


  An atom donates electrons to another atom, creating a bond
• Covalent bonds


  Two atoms share electrons
• Bond polarity


  Molecular polarity and electronegativity
• Water is very polar


  • Oxygen is a very electronegative element, hogging electrons to itself
• Hydrogen bonds


  Water molecules form many hydrogen bonds with each other
• Hydrogen bonds will come up again and again throughout biology; keep an eye out for it!
• Properties of water


  • Cohesion, adhesion, surface tension
  • Keeps temperatures moderate through evaporative cooling and a high specific heat
  • Ice floats on top of liquid water
  • Acts as a universal solvent
• Acids


  Increase the concentration of H+ ions in solution
• Ocean acidification


  • Carbon dioxide dissolves into the ocean, creating carbonic acid
• Bases


  Decrease the concentration of H+ ions in solution
• Buffers


  A substance that limits any significant changes in H+ concentration
• Carbonic acid in our blood

  • Regulates our blood pH
• Organic compounds


  Compounds that contain carbon
• Organic chemistry


  The study of how organic compounds interact
• Shapes and types of organic molecules

  • Carbons are usually the central atom
  • They can form single, double, or triple bonds with other atoms
• Hydrocarbons


  Organic molecules that contain only carbon and hydrogen
• Organic molecules can be branched, straight chains (such as hydrocarbons), or rings
• Functional groups


  Be familiar with their general structure and special properties
• ATP (adenosine triphosphate)


  • Has 3 phosphate groups and is what our cells use for energy
• Diamonds are made of pure carbon and they are known as the hardest substance on Earth because of the special crystal structure (called diamond cubic) holding the carbon atoms together
• Rice is full of starch


  • Enzymes in your mouth break down the starch into glucose molecules
• Macromolecules


  • Macromolecules synthesis and breakdown
  • Dehydration and hydrolysis reactions
• Types of macromolecules


  • Carbohydrates
  • Proteins
  • Nucleic acids
  • Lipids
• Glycosidic linkages


  Covalent bonds linking monosaccharides together in a polysaccharide
• Main polysaccharides


  • Starch
  • Glycogen
  • Cellulose
  • Chitin
  • Peptidoglycan
• Glycogen and starch are branched, while cellulose is linear in structure
• Disaccharides


  • Sucrose
  • Maltose
  • Lactose
• Monosaccharides


  • Glucose
  • Fructose
  • Galactose
• DNA


  • Has the sugar deoxyribose, the nitrogenous bases A, T, C, and G, and a sugar-phosphate backbone
  • Typically a double-stranded helix
• RNA


  • Has the sugar ribose and the nitrogenous bases A, U, C, and G
  • Usually single-stranded
• DNA and RNA store hereditary information that can be passed on to offspring
• Triacylglycerol


  Important source of energy in animals, made of 1 glycerol and 3 fatty acid chains
• Phospholipids


  The building block of the cell membrane lipid bilayer, with a hydrophilic phosphate head and hydrophobic fatty acid tails
• Steroids


  The structure consists of 4 fused carbon rings, examples include cholesterol and steroid hormones
• Cholesterol


  A type of steroid found in the cell membrane, important for maintaining membrane fluidity
• Amino acids


  The building blocks of proteins, there are 20 unique amino acids with unique side chains (R groups)
• Protein functions


  • Enzymes (biological catalysts), structural support, transport, hormones, receptors, motor proteins, defensive proteins like antibodies
• Four stages of protein structure

  • Primary structure (sequence of amino acids)
  • Secondary structure (hydrogen bonds forming alpha pleated sheets or beta-helix)
  • Tertiary structure (chemical interactions between side chains)
  • Quaternary structure (multiple peptide chains joining)
• Macromolecules


  The four main types are carbohydrates, proteins, nucleic acids, and lipids
• Carbohydrates


  • Made up of carbon, hydrogen, and oxygen in a 1:2:1 ratio
  • Monomers are monosaccharides like glucose, fructose, galactose
  • Can form disaccharides (2 monosaccharides) and polysaccharides (long chains)