2. Biochemistry

3. Particles of Matter An element is a substance made of only one type of atom A compound is made of more than one type of atom (ex. CO 2, H 2 O) An atom is the smallest part of an element that has the same properties as the element A molecule is the smallest part of a compound that has the same properties as the compound

4. Structure of an Atom Nucleus Protons And Neutrons electrons - charge _ + charge 0 charge

5. Sub-Atomic Particles Protons and neutrons make up the mass of the atom (atomic mass) The arrangement of electrons determines the chemical properties of the atom (how it behaves in a chemical reaction)

6. Isotopes Atoms of the same element that differ in their number of neutrons Some isotopes are unstable and give off radiation (radioisotopes)

7. Radioisotopes Uses of radioisotopes: Used to treat cancer (radiation kills cancer cells) Used to date fossils Used in medical imaging (radioactive tracers)

8. What is an ION? An atom or group of atoms with a charge (either + or -) Ions are involved in thousands of chemical processes in the body

9. Acids, Bases, and Buffers

10. What is an acid? -any substance that forms hydrogen ions (H + ) in a solution Examples of acids: HCl H 2 SO 4 HNO 3

11. What is a base? -any substance that forms hydroxide ions (OH - ) in a solution Examples of bases: NaOH KOH Ca(OH) 2

12. pH Scale -measures the concentration of H + ions in a solution 014 7 ACIDIC BASIC *A change is one on the pH scale represents a 10 fold increase in H+ ions Ex. pH of 3 is 10 times more acidic than pH 4 pH of 3 is 100 times more acidic than pH 5 Pure H 2 O

13. What is a Buffer? A buffer is a substance that neutralizes excess acids or bases to keep the pH of a solution constant Buffers are present in all of the cells and fluids in your body