2. Regents Biology 2006-2007 The Chemistry of Life What are living creatures made of? Why do we have to eat?

3. Regents Biology  96% of living organisms is made of: carbon (C) oxygen (O) hydrogen (H) nitrogen (N) Elements of Life

4. Regents Biology The World of Elements

5. Regents Biology Ionization of water & pH  Water ionizes -H + splits off from H 2 O, leaving OH – -if [H + ] = [ - OH], neutral = 7 -if [H + ] > [ - OH], acidic = 0-6.9 -if [H + ] < [ - OH], basic = 8-14  pH scale  how acidic or basic a solution is  0  7  14 H 2 O  H + + OH –

6. Regents Biology pH Scale 10 –1 H + Ion Concentration Examples of Solutions Stomach acid, Lemon juice 1 pH 10 0 Hydrochloric acid0 10 –2 2 10 –3 Vinegar, cola, beer 3 10 –4 Tomatoes 4 10 –5 Black coffee, Rainwater 5 10 –6 Urine, Saliva 6 10 –7 Pure water, Blood 7 10 –8 Seawater 8 10 –9 Baking soda 9 10 –10 Great Salt Lake 10 10 –11 Household ammonia 11 10 –12 Household bleach 12 10 –13 Oven cleaner 13 10 –14 Sodium hydroxide14

7. Regents Biology pH & cellular regulation  pH of cells must be kept ~7 -pH affects shape of molecules -shape of molecules affect function -pH affects cellular function 10 0 1 2 3 4 5 6 7 8 9 3 Amount of base added Buffering range 452 pH

8. Regents Biology Molecules of Life  Put C, H, O, N together in different ways to build living organisms  What are bodies made of?  carbohydrates  sugars & starches  proteins  fats (lipids)  nucleic acids  DNA, RNA

9. Regents Biology Why do we eat?  We eat to take in more of these chemicals  Food for building materials  to make more of us (cells)  for growth  for repair  Food to make energy  calories  to make ATP ATP

10. Regents Biology

11. What do we need to eat?  Foods to give you more building blocks & more energy  for building & running bodies  carbohydrates  proteins  fats  nucleic acids  vitamins  minerals, salts  water

12. Regents Biology  Water  65% of your body is H 2 O  water is inorganic  doesn’t contain carbon  Rest of you is made of carbon molecules  organic molecules  carbohydrates  proteins  fats  nucleic acids Don’t forget water

13. Regents Biology

14. 2006-2007 How do we make these molecules? We build them!

15. Regents Biology Building large molecules of life  Chain together smaller molecules  building block molecules  Big molecules built from little molecules  polymers

16. Regents Biology  Small molecules = building block (monomers-glucose)  Bond them together = polymers (starch) Building large organic molecules

17. Regents Biology Building important polymers sugar – sugar – sugar – sugar – sugar – sugar nucleotide – nucleotide – nucleotide – nucleotide (Nucleotide=sugar,phosphate,base) Carbohydrates = built from sugars Proteins = built from amino acids Nucleic acids (DNA) = built from nucleotides amino acid amino acid – amino acid – amino acid – amino acid – amino acid –

18. Regents Biology

19. How to build large molecules  Synthesis  building bigger molecules from smaller molecules  building cells & bodies + ATP

20. Regents Biology How to take large molecules apart  Digestion (hydolysis)  taking big molecules apart  getting raw materials  making energy (ATP) + ATP Disaccharide=2 sugars 2 monosaccharides

21. Regents Biology

23. Example of digestion starchglucose ATP  Starch is digested to glucose

24. Regents Biology

25. Example of synthesis amino acidsprotein  Proteins are synthesized by bonding amino acids