ap bio unit 1

• secondary protein structure: alpha helix and beta pleated sheets are held in shape by hydrogen bonds
• lactose intolerance: small intestines don't produce enough of the enzyme lactase to break down lactose
• hydrogen bonds are intermolecular and form between the positive hydrogen of one water molecule and the negative oxygen of another water molecule

  • much WEAKER than covalent or ionic bonds
• cohesion:

  • hydrogen bonds between water molecules
  • responsible for water's high heat of vaporization, specific heat, and surface tension
• adhesion:

  • hydrogen bonds between water molecules and other POLAR substances (cellulose walls making up the xylem of plants)
  • responsible for capillary action (adhesion > cohesion)
  • transpiration: caused by the negative pressure in the xylem that pulls water towards the stomata for evaporation
• surface tension:

  • force exerted by the water molecules on the surface of a body of water
  • creates a kind of web or net upon the surface (water striders, resisting evaporation, etc.)
• acidic solutions:

  • pH < 7
  • more hydrogen ions than hydroxide ions
• bases:

  • pH > 7
  • more hydroxide than hydrogen ions
• CHONPS:

  • carbon: central element of structures
  • hydrogen: as an ion, used to create proton gradients
  • phosphate: phosphate groups in ATP
• dehydration synthesis:

  • enzymes pull out H2O to create a bond between 2 monomers

  hydrolysis:

  • enzymes insert an H2O molecule to break the bonds making up a polymer
• functional groups:

  • phosphates: key for energy exchange (PO4)
  • methyl: used to turn off DNA (methylation) (CH3)
  • polar functional groups: hydroxyl (OH) and carbonyl (CO), making a molecule hydrophilic/water soluble
  • carboxyl (COOH) and amino (NH3): essential in amino acids
  • sulfhydryl (SH): important in protein structure
  • acetyl (COCH3): used to activate DNA (acetylation)
• monosaccharides: glucose, fructose, galactose

  disaccharides: sucrose, lactose, maltose

  polysaccharides: long chains of monosaccharides linked by glycosidic bonds

  • energy storage (starch in plants, glycogen in animals)
  • structural (cellulose in cell walls of plants)
• functions of lipids:

  • energy storage (fats/oils)
  • waterproofing (waxes)
  • membrane formation (phospholipids)
  • signaling (steroids)
• primary protein structure:

  • singular polypeptide chain
  • created by ribosomes during translation/protein synthesis
  • connected by peptide bonds (covalent bonds)
• tertiary protein structure:

  • interactions between side chains (R-groups) of different amino acids to form 3D shape
  • involves hydrogen, ionic, covalent, and hydrophobic clustering
  • sulfhydryl bonds are important for tightly holding the protein
• quaternary protein structure:

  • involves multiple polypeptides
  • can involve hydrogen, ionic, and hydrophobic interactions
• hemoglobin function: transports oxygen in red blood cells

  structure: 4 polypeptide chains
• sickle cell disease: caused by a recessive mutation (the amino acid valine, nonpolar, substitutes glutamic acid, polar)

  • when blood becomes deoxygenated, the mutated hemoglobin molecules form hydrophobic bonds with one another, creating fibers
  • consequences: reduction in oxygen-carrying capacity and the deformation in the shape of red blood cells (sickle-shaped)
• ATP (an RNA monomer): life's key energy transfer molecule, powering more cellular work
• each nucleotide on DNA are connected by phosphodiester bonds (covalent bonds)

  • each nitrogenous based is connected by a hydrogen bond
• triglycerides: glycerol bonds with 3 fatty acids through dehydration

  • connected through ester bonds
• saturated fat: saturated by hydrogen

  • solid at room temperature
  • no double bonds
  • dense

  unsaturated fat: less hydrogens

  • liquid at room temperature
  • kinks formed, less dense
  • one or more double bonds
  • ex. oils
• functions of carbohydrates:

  • short term energy
  • source of dietary fiber
• functions of proteins:

  • provide cell structure
  • send chemical signals
  • speed up chemical reactions
• polynucleotide structure:

  • nitrogenous base
  • 5-carbon sugar
  • phosphate group
• purine: adenine and guanine, 2 rings
• pyrimidine: thymine, uracil, and cytosine, 1 ring
• 5' phosphate group

  3' hydroyxl group of the last nucleotide
• Monomers will be connected by covalent bonds to form polymers:

  • monosaccharides- glycosidic linkages
  • amino acids- peptide bonds
  • nucleotides- phosphodiester bonds
• miller urey experiment:

  • water was heated and the water vapor was mixed with hydrogen, carbon dioxide and monoxide, nitrogen, ammonia, and methane
  • the heated mixture goes up with the gases and is sparked with electricity to simulate lighting
  • the gases were cooled using a glass tube filled with circulating cold water
  • amino acids and hydrocarbons formed!
  • proved that life could originate from inorganic compounds
  • they assumed that electric sparks occurred to catalyze reactions
• nucleotides are added to the 3' end of RNA during RNA synthesis
• protein structure:

  • amino (NH2) group (start)
  • carboxyl (COOH) group (end, where covalent bonds are formed when adding amino acids to chain)
• water's high heat of vaporization (amount of energy to convert liquid to gas) is how organism's cool themselves through the evaporation of sweat

  • our body's heat is used to cool off the sweat, so since water has a high heat of vaporization, we need to use more heat to evaporate sweat, allowing us to become cooler faster
• DNA is negatively charged due to the phosphate backbone and the 5’ end phosphate group, so it moves towards the positive electrodes during gel electrophoresis
• we can break down starch because it has 1, 4 alpha linkages, but we cannot break down cellulose because it has 1, 4 beta linkages
• water's high specific heat (ability to resist change in temperature) allows water to absorb heat during the day to maintain a stable temperature and release heat at night so we feel a warm breeze

  • water's evaporative cooling allows us to maintain body temperature through the evaporation of sweat
• glucose is polar, thus covalent bonds within C, H, and O