physical science

• Large Biological Molecules


  Critically important molecules in all living things divided into 4 classes: Lipids (fats), Carbohydrates (sugars), Proteins, Nucleic Acids (DNA & RNA)
• Carbohydrates, Proteins and Nucleic Acids are Polymers

  
• Polymers


  Large molecules made of covalently bonded monomers (building blocks)
• Polymer formation


  1. Dehydration synthesis

  2. Hydrolysis
• The order of the monomers determines the function and shape of the polymer

  
• Carbohydrates


  Carbon & water compounds with a 2:1 ratio of H to O, can exist as rings or linear

  
• Monosaccharides


  • Simple sugars, generally have molecular formulas that are some multiple of the unit CH2O, provide quick energy for cells

  
• Monosaccharides


  • Glucose (aldose), Fructose (ketose)

  
• Disaccharides


  Consist of 2 monosaccharides joined by a glycosidic linkage

  
• Disaccharides


  • Sucrose (glucose + fructose), Lactose (glucose + galactose)

  
• Polysaccharides


  • Many saccharides, used for energy storage (starch, glycogen) or structural support (cellulose, chitin)

  
• Lipids


  Hydrophobic, mostly hydrocarbons with non-polar covalent bonds

  
• Triglycerides


  Fats, 3 fatty acids joined to glycerol

  
• Saturated vs Unsaturated Fats


  • Saturated have all single bonds between C atoms, solid at room temp. Unsaturated have double/triple bonds, liquid at room temp.

  
• Phospholipids


  Main component of cell membranes, have a hydrophobic tail and hydrophilic head
• Steroids


  Lipids characterized by a carbon skeleton of 4 fused rings, include cholesterol and hormones

  
• Trans fats are artificially made fats that cannot be broken down, leading to heart disease
• Polypeptides


  Polymers of amino acids joined by peptide bonds

  
• Amino Acids


  Contain an amine group and a carboxyl group, 20 different types with varying properties
• Protein Structure


  • Primary: amino acid sequence, Secondary: alpha helix or beta pleated sheet, Tertiary: 3D folding, Quaternary: multiple polypeptide chains

  
• Errors in protein folding can cause diseases like Alzheimer's, Parkinson's, and sickle cell anemia
• Denaturation


  The unfolding of a protein, depends on chemical and physical conditions like pH, ionic concentration, and temperature
• Nucleic Acids


  DNA and RNA, store and transmit genetic information, proteins are made from info in nucleic acids
• Nucleotides


  Monomers of nucleic acids, contain a sugar (ribose or deoxyribose), phosphate, and a base (purines: A, G, pyrimidines: C, T)
• Proteins are made from information in nucleic acids
• DNA replication and protein synthesis occur through a process involving the nucleus and cytoplasm
• Graphic Organizer for the Large Biological Molecules

  • Proteins
  • Carbohydrates
  • Lipids
  • Nucleic Acids

  
• •Starch(potatoes, rice, and grains. ) plants.

  ·          Amylose - unbranched

  ·         Amylopectan - branched 

  • Glycogen - animals, liver and muscle energy stores

  • Structure and support (beta glucose) - straight

  • Cellulose - plants, structural support creates a cable like structure called microfibrils by H-bonding to adjacent cellulose molecules

  • Chitin - exoskeletons and fungi

                 • Contains nitrogen
• • Denaturation - the unfolding of a protein

  • Depends on chemical and physical conditions

  • pH, lonic concentration, temperature

  • Chaperonins - aid in the folding process
• Steroids

  • Lipids characterized by a carbon skeleton of 4 fused rings

  • Cholesterol and many other hormones (sex hormones) important in cell membranes

  • Too much builds up in the arteries = atherosclerosis

  • Trans fats: artificially made fats, no enzymes to break them down = heart disease
• Collision theory


  1. Particles of reactants must collide at precisely the correct angle and proper amount of energy in order for chemical reaction to occur

  2. The more collisions, the faster the rate of chemical reaction
• Collision theory


  • Shows the relationship between particle collisions and reaction rate
• Factors affecting reaction rate according to collision theory

  • Concentration
  • Particle size
  • Temperature
  • Catalysts
• Catalyst


  Lowers the activation energy required so that molecules can start to collide with each other
• For chemical changes to occur, a certain amount of energy called activation energy is needed by reactants
• Reaction rate


  The duration when chemical reactions might happen
• The study of reaction rate is called KINETICS
• Concentration of substances

  Higher concentration has more particles available for collision, leading to faster rate of reaction
• Particle size

  Smaller particles dissolve faster
• Temperature increase


  Increases rate of reaction