1. Chemical Basis of Life

2. Ionic Bonding http://www.es.ucsc.edu/~es10/classnotes/lectures/ionic.bond.jpg

3. Covalent Bonding http://www.gcsescience.com/Methane-Molecule.gif http://media-2.web.britannica.com/eb-media/04/96904-004-C880B85D.gif

4. Hydrogen Bonding http://upload.wikimedia.org/wikipedia/commons/f/f9/3D_model_hydrogen_bonds_in_water.jpg http://schools-wikipedia.org/images/646/64609.png

5. Properties of Water 1. Strong Polarity: Polar water molecules attract other polar compounds causing them to dissociate –Water is a great solvent Many molecules can dissolve in cells (mostly water) –Allows for chemical reactions and transportation

6. Properties of Water 2. High Specific Heat Hydrogen bonds absorb heat when broken and release heat when formed –This minimizes temperature changes in the body –Body temp remain relatively constant 3.High Heat of Vaporization Energy needed to break H+ bonds Body can dissipate excess heat & maintain a normal body temperature by evaporation

7. Properties of Water 4.Cohesion Water molecules provide lubrication or cushioning to protect against damage from friction or trauma

8. Electrolytes Substances that dissociate (break up) in solution to form charged particles or ions. –Examples: Acids, bases, salts –Cations: positive charged ions –Anions: negative charged ions

9. Acids & Bases Acid – any substance that releases H+ when in solution –“proton donor” –Ex: HCl (stomach acid) Base – any substance that increases the OH- concentration when dissociated in solution –“proton acceptor” –“Ex: NaOH

10. pH Scale Represents the H+ ion concentration in a solution 7 = neutral 0-6 = acidic 8-14 = basic/alkaline

11. Buffers Any molecule that moderates changes in pH. –Key role in the body’s ability to maintain a normal pH (homeostasis) Many buffers are anions that have a strong affinity for H+ –bicarbonate ion (HCO 3 - ) is an important buffer in the human body

12. Carbohydrates Building Block – Monosacchride Disaccharides – 2 monosacchrides covalently bonded Polysaccharides – complex carbohydrates

13. Carbohydrates Structure: –Contains the elements C, H, O H and O always in 2:1 ratio –Monosaccharides form short carbon chain Ex: Glucose (C 6 H 12 O 6 ) Function: –Provide energy for cellular activities –Structural support in DNA (deoxyribose) and RNA (ribose)

14. Lipids Includes: fats, phospholipids, steroids and prostaglandins –Water insoluble 1.Fats/Triglycerides: –Structure: glycerol & 3 fatty acid tails –Function: concentrated energy source http://www.future-of-technology.com/web_images/triglyceride.jpg

15. Lipids cont…. 2.Phospholipids –Structure: glycerol, 2 fatty acid tails & a phosphate group Head: water soluble (“hydrophilic”) Tails: fat soluble (“hydrophobic”) –Function: main component of cell membrane http://www.fz-juelich.de/isb/isb-1/datapool/page/28/Figure1-500.jpg

16. Lipids cont…. 3.Steroids –Cholesterol: Provides stabilization function in cell membrane –Other examples: estrogen & testosterone 4. Prostaglandins

17. Proteins Wide range of functions: –Defense system (antibodies) –Serve as receptors or binding sites –Structural (skin, tendons, nails) –Catalyze chemical reactions (enzymes) –Communication (insulin – protein hormone)

18. Amino Acids Building blocks of proteins –20 amino acids –8 are essential (must be obtained through diet) –Structure: Amine group Carboxyl group Side chain (determines unique properties of amino acid) http://www.aloeveraibs.com/wp-content/uploads/2008/08/aminoacidstruc.jpg

19. Enzymes Largest group of proteins in the body. Chemical catalyst –Assist in chemical reactions but are not products nor reactants –Not changed by the reaction –Usually end in -ase

20. Nucleic Acids Form genes and take part in protein synthesis Building block – nucleotide –Phosphate –Nitrogen Base (Adenine, Guanine, Cytosine, Thymine) –5-carbon sugar (deoxyribose in DNA) Ex: DNA, RNA http://bbruner.org/bitn/bitn_fig/dna.gif

21. Metabolism All the chemical reactions that take place in our body’s cells. –Catabolism: Chemical reaction that breaks down large molecules into smaller units. This type of reaction releases energy. Also called a hydrolysis reaction because a water molecule is added for the reaction to occur. –Anabolism: Chemical reaction that combines smaller molecules to form larger molecules. This type of reaction requires energy, usually ATP. Also called a dehydration synthesis reaction because a water molecule is removed during the reaction. –Fig 2-25, p. 61