2. Matter: Atoms and Molecules
Smallest unit of an element
Subatomic particles
Protons: (+) charge
Neutrons: neutral
Electrons: (-) charge
Figure 2-1

3. Matter: Atoms and Molecules
Structure of atom
Electrons surround nucleus
Electrons organized in shells
The outer shell determines chemical properties

4. Matter: Atoms and Molecules
Key Note
All matter is composed of atoms in various combinations. Their interactions establish the foundations of physiology at the cellular level.

5. Matter: Atoms and Molecules
Ionic Bonds
Atoms gain or lose electrons
Charged atoms are ions
Ions bear (+) or (-) charge
Cations have (+) charge
Anions have (-) charge
Cations and anions attract
Ions form bonds

6. Matter: Atoms and Molecules
Table 2-2

7. Chemical Reactions Metabolism All the chemical reactions in the body
Consumes reactants
Produces products
Breaks or makes chemical bonds between atoms

8. Chemical Reactions Basic Energy Concepts
Potential energy—stored energy
E.g., glycogen stored in muscle cells
Kinetic energy—energy of movement
E.g., leopard pounces on prey

9. Inorganic Compounds Nutrients
Essential elements and molecules obtained from the diet
Metabolites
Molecules synthesized or broken down by chemical reactions inside the body

10. Inorganic Compounds Inorganic
Smaller molecules such as water, oxygen and ions that lack carbon and hydrogen
Organic
Larger molecules such as sugars, proteins, and fats composed largely of carbon, hydrogen and oxygen

11. Human Body Composition
Element
Percent by mass
Oxygen 65
Carbon 18
Hydrogen 10
Nitrogen 3
Calcium
1.5
Phosphorus
1.2
Potassium
0.2
Sulfur
Chlorine
Sodium
0.1
Magnesium
0.05
Iron, Cobalt, Copper, Zinc, Iodine
<0.05 each
Selenium, Fluorine
<0.01 each

12. Organic Compounds Carbohydrates
Most important energy source for metabolism
Three major types
Monosaccharides (E.g., glucose)
Disaccharides (E.g., sucrose)
Polysaccharides (E.g., glycogen)

13. Organic Compounds
Glucose
Figure 2-10

14. Organic Compounds
Formation of Glycogen
Figure 2-11(c)

15. Organic Compounds Lipids Water-insoluble Four important classes
Fatty acids
Fats
Steroids
Phospholipids

16. Organic Compounds
Fatty Acids
Figure 2-12

17. Organic Compounds Cholesterol Building block for steroid hormones
Component of cell membranes
Figure 2-14

18. Organic Compounds Proteins
Most abundant organic component in human body
About 100,000 different proteins
Contain carbon, nitrogen, oxygen, hydrogen, and a bit of sulfur

19. Organic Compounds Proteins play vital roles Support Movement Transport
Buffering
Regulation
Defense

20. Organic Compounds
Proteins are built from amino acids
Figure 2-16(a)

21. Protein Structure
Figure 2-17

22. Organic Compounds Enzyme Function
Substrates (reactants) bind to active site on enzyme surface
Binding lowers activation energy needed for reaction
Substrates react to form product
Product is released from enzyme surface

23. Enzyme function made simple
Figure 2-18

24. Organic Compounds Nucleic Acids Large molecules
Built from atoms of C, H, O, N, and P
Store and process molecular information
Two classes of nucleic acid
DNA (deoxyribonucleic acid)
RNA (ribonucleic acid)

25. The Structure of Nucleic Acids
Figure 2-19ab

26. The Structure of Nucleic Acids

27. Organic Compounds Structure of Nucleic Acids
Nucleotides contain a sugar, a phosphate, and a base
Sugar-phosphate bonds link nucleotides in long strands
Hydrogen bonds hold two DNA strands in a double helix

28. Summary of Body Chemistry
Organic Chemical Building Blocks
Figure 2-22