1. CHEMISTRY OF LIVING THINGS Chapter 2

2. © 2004 Delmar Learning, a Division of Thomson Learning, Inc. CHEMISTRY Defined as the study of the structure of matter and the composition of substances, their properties, and their chemical reactions Biochemistry is the study of chemical reactions of living things

3. © 2004 Delmar Learning, a Division of Thomson Learning, Inc. MATTER AND ENERGY Matter is anything that has weight and occupies space; it is neither created nor destroyed Energy is the ability to do work or to put material into motion and exists in the body as: –Potential energy –Kinetic energy

4. © 2004 Delmar Learning, a Division of Thomson Learning, Inc. ATOMS An atom is the smallest piece of an element Atoms are made of subatomic particles –Protons have a positive charge –Neutrons have no charge –Electrons have a negative charge

5. © 2004 Delmar Learning, a Division of Thomson Learning, Inc. ATOMS Isotopes are atoms of a specific element with the same number of protons but a different amount of neutrons –Radioactive Isotopes are unstable and may decay

6. © 2004 Delmar Learning, a Division of Thomson Learning, Inc. ELEMENTS Atoms that are alike combine to form elements There are 92 elements found naturally and each is represented by a chemical symbol or abbreviation

7. © 2004 Delmar Learning, a Division of Thomson Learning, Inc. COMPOUNDS Organic compounds are compounds found in living things containing the element carbon Molecules are the smallest units of compounds that retain its properties and remain stable

8. © 2004 Delmar Learning, a Division of Thomson Learning, Inc. IONS AND ELECTROLYTES Ions are atoms that have more protons than electrons; creating a positive charge Electrolytes are atoms that have more electrons than protons; creating a negative charge

9. © 2004 Delmar Learning, a Division of Thomson Learning, Inc. TYPES OF COMPOUNDS Inorganic Compounds –Made of molecules that do not contain carbon (C) Organic Compounds –Always contain the element carbon (C) –4 Groups of organic compounds are: Carbohydrates Proteins Lipids Nucleic acids

10. © 2004 Delmar Learning, a Division of Thomson Learning, Inc. CARBOHYDRATES All carbohydrates are compounds of carbon, hydrogen, and oxygen 3 Groups of carbohydrates: –Monosaccharides –Disaccharides –Polysaccharides

11. © 2004 Delmar Learning, a Division of Thomson Learning, Inc. LIPIDS Lipids contain less oxygen than hydrogen Examples of lipids: –Fats –Phospholipids –Steroids

12. © 2004 Delmar Learning, a Division of Thomson Learning, Inc. PROTEINS Proteins are among the most diverse and essential organic compounds found in all living things Amino acids are the small units that make up protein molecules Enzymes are specialized protein molecules that help control chemical reactions in a cell

13. © 2004 Delmar Learning, a Division of Thomson Learning, Inc. NUCLEIC ACIDS Nucleic acids are the largest known organic molecules; made from thousands of repeating subunits called nucleotides There are two major types of nucleic acids: –DNA –RNA

14. © 2004 Delmar Learning, a Division of Thomson Learning, Inc. ACIDS, BASES, AND SALTS Acids are substances that yield hydrogen ions in solution Bases are substances that ionize into negatively charged hydroxide ions and positively charged ions of metal when dissolved in water Salts are formed when acids and bases are combined

15. © 2004 Delmar Learning, a Division of Thomson Learning, Inc. PH SCALE pH measures acidity or alkalinity of a solution The pH scale ranges from 0 to 14 –A pH between 0 and 6.9 is acidic –A pH between 7.1 and 14 is alkaline –A pH of 7.0 is neutral as it contains the same number of hydrogen and hydroxide ions