Chapter 8: Nutrients, Enzymes, & The Digestive System

• Chemicals of Life


  • Carbohydrates
  • Proteins
  • Lipids
  • Nucleic Acids
  • Vitamins and Minerals
• Carbohydrates


  • Cells' primary source of energy
  • Material that makes the structure of plant cell walls
• Proteins


  • Structural components of the cell
  • Made of amino acids
• Lipids


  • Energy storage compounds
  • Structural component of cell membranes
• Nucleic Acids


  • Genetic material directing cell activity
  • Made of sugar, phosphate, and nitrogen bases
• Vitamins and Minerals


  • Helps in chemical reactions
  • Usually found in complex chemicals
• Most foods we eat are made of a combination of nutrients and classified into carbohydrates, proteins, and lipids
• Vitamins and minerals are also required, but in smaller amounts
• Water is also required but not considered a nutrient
• Some chemicals that your body requires are inorganic: water, phosphates, potassium, sodium, hydrogen ions, etc.
• Macromolecules


  Organic molecules containing carbon atoms bonded to hydrogen atoms, and sometimes oxygen, sulfur and nitrogen
• Macromolecules


  • Carbohydrates
  • Proteins
  • Lipids
  • Nucleic Acids
• Metabolism


  The chemical reactions that take place within a cell to support and sustain its life functions
• Types of metabolic reactions

  • Dehydration Synthesis
  • Hydrolysis
• Dehydration Synthesis


  The process by which larger molecules are formed by the removal of water from two smaller molecules
• Hydrolysis


  The process by which larger molecules are split into smaller molecules by the addition of water
• Carbohydrates


  A molecule composed of sugar subunits that contain carbon, hydrogen, and oxygen in a 1:2:1 ratio
• Carbohydrates


  • Provides short-term or long-term energy storage for the body
  • Make up the largest component in most diets
• The human body cannot make carbohydrates, but plants can (photosynthesis)
• Polymer


  A molecule composed of three or more subunits
• Monosaccharides


  • Glucose
  • Galactose
  • Fructose
• Isomers


  One group of chemicals that have the same chemical formula but different arrangements of atoms
• Disaccharide


  A sugar formed by the joining of two monosaccharide subunits
• Disaccharides


  • Sucrose (white table sugar)
  • Maltose (malt sugar)
  • Lactose (milk sugar)
• Polysaccharide


  A carbohydrate composed of many monosaccharide/single sugar subunits
• Polysaccharides


  • Starch
  • Amylose
  • Amylopectin
  • Glycogen
  • Cellulose
• Lipids


  • Non-polar compounds (i.e. fats and oils)
  • Insoluble in polar solvents (i.e. water)
• Lipids


  • Important for storing energy in the form of fat
  • Key components in cell membranes
• Triglycerides


  A lipid composed of glycerol and three fatty acids
• Phospholipids


  A lipid with a phosphate molecule attached to the glycerol backbone, making the molecule polar
• Waxes


  A long-chain lipid that is insoluble in water
• Doctors recommend no more than 30% of our diet being fats
• When energy intake exceeds energy output

  The result is weight gain
• High-fat diets have been linked to certain cancers (i.e breast, colon, and prostate)
• High-fat diets have been linked to high blood pressure and diabetes
• LDL (Low-Density Lipoprotein)


  Forms deposits in the walls of arteries
• HDL (High-density lipoprotein)


  Carries bad cholesterol back to the liver where it is broken down
• Trans fats lower the HDL and raise the LDL in our bodies
• Protein


  A chain of amino acids that form the structural parts of cells or act as antibodies or enzymes
• Proteins


  • Used to repair cell damage
  • Not generally used as an energy source
  • Cells can also make their proteins to build structures for new cells