PL 2.1

• Major elements in the body

  • Oxygen, Carbon, Hydrogen, Nitrogen
• A normal, lean adult body is 12–18% protein. Proteins are largely responsible for the structure of body tissues and include keratin, collagen, digestive enzymes, antibodies, neurotransmitters, and peptide-based hormones
• Inorganic compounds lack carbon and are structurally simple. They can have ionic or covalent bonds. They include water and many salts, acids, and bases
• Water consists of one atom of oxygen joined by polar covalent bonds to two atoms of hydrogen
• Shape of Proteins

  1. Primary structure: sequence of amino acids

  2. Secondary structure: alpha-helix or beta-pleated sheet maintained by hydrogen bonds

  3. Tertiary structure: further folding and bonding of the secondary structure

  4. Quaternary structure: interactions between two or more tertiary subunits
• Proteins are large molecules that contain carbon, hydrogen, oxygen, nitrogen, and sulfur. They are composed of amino acids linked by peptide bonds
• Lesser elements in the body

  • Calcium, Phosphorus (P), Potassium (K), Sulfur (S), Sodium, Chlorine (Cl), Magnesium (Mg), Iron (Fe)
• States of matter

  • Solid
  • Liquid
  • Gas
• Anything that occupies space and has mass, either living or nonliving things consist of matter
• Trace elements in the body

  • 0.2% of the body’s mass
• Organic compounds always contain carbon, usually contain hydrogen, and always have covalent bonds. Most are large molecules and many are made up of long chains of carbon atoms
• Properties of Water

  1. Water as a solvent

  2. Water in chemical reactions

  3. Hydrolysis reactions

  4. Dehydration synthesis reactions

  5. Thermal properties of water

  6. Water as a lubricant
• Amino acids


  A molecule composed of an amino group and a carboxyl group, together with a variable side chain
• All forms of matter are made up of a limited number of building blocks called chemical elements
• Chemistry


  The science of the structure and interactions of matter
• Water makes up 55–60% of a lean adult’s total body mass. It is the most abundant inorganic compound in all living systems and is considered the most important
• Number of chemical elements

  • 117 elements: 92 naturally occurring, 25 artificially produced
• Peptide bond


  The unique bond holding amino acids together
• Primary structure of proteins

  Sequence of amino acids that make up the polypeptide chain
• Carbohydrates


  Represent only 2–3% of total body mass; function mainly as a source of chemical energy for generating ATP needed to drive metabolic reactions; elements found in carbohydrates are carbon, hydrogen, and oxygen; the ratio of hydrogen to oxygen atoms is usually 2:1, the same as in water; term translates to “watered carbon”
• Phosphorus


  1.0% of the total body mass; component of nucleic acids and ATP; required for normal bone and tooth structure
• Oxygen


  65% of the total body mass; part of water and many organic (carbon-containing) molecules; used to generate ATP, a molecule used by cells to temporarily store chemical energy
• Nitrogen

  3.2% of the total body mass; a component of all proteins and nucleic acids
• Carbon


  Can form bonds with one to thousands of other carbon atoms to produce large molecules that can have many different shapes; the chain of carbon atoms in an organic molecule is called the carbon skeleton
• Minerals


  Inorganic nutrients essential for normal metabolic functions; constitute about 4-5% of total body weight; known minerals include calcium, phosphorus, potassium, sulfur, sodium, chloride, magnesium, iron, iodide, manganese, copper, cobalt, zinc, fluoride, selenium, and chromium
• Quaternary structure of proteins

  Occurs as a result of interactions between two or more tertiary subunits; example shown is hemoglobin, a protein in red blood cells which transports oxygen to body tissues
• Tertiary structure of proteins


  Occurs as a result of further folding and bonding of the secondary structure
• Secondary structure of proteins


  Maintained by hydrogen bonds between amino acids in different regions of the original polypeptide strand; can take the form of an alpha-helix or a beta-pleated sheet
• Lipids


  Make up 18–25% of body mass in lean adults; contain carbon, hydrogen, and oxygen; are hydrophobic; join together with hydrophilic proteins to become more soluble in the blood plasma, these protein complexes are called lipoproteins
• Calcium


  1.5% of the total body mass; contributes to the hardness of bones and teeth; ionized form (Ca2) needed for blood clotting, release of some hormones, contraction of muscle, and many other processes
• Fatty acids


  Synthesize triglycerides & phospholipids for ATP
• Steroids


  Minor component of animal cell membranes (bile salts, V-D, steroid)
• Triglycerids


  Protect, insulation, energy storage
• Phospholipids


  Major lipid component of cell membrane
• Vitamin E


  • Help wound heal
  • Prevent tissue scar
  • Help function nervous system
  • Antioxidant
• Vitamin K


  Combine blood-clotting proteins
• Carotenes


  • Synthesis V-A (eyes)
  • Antioxidants
• Vitamin D


  • Regulate calcium lvl
  • Bone growth at repair
• Lipoproteins


  • Transport lipid into blood
  • Carry triglycerides & cholesterol to tissue
  • Remove excess cholesterol from blood