Chapter 2 Chemical Basis of Life

1. Chapter 2Chemical Basis of Life Why study chemistry in an Anatomy and Physiology class? - body functions depend on cellular functions - cellular functions result from chemical changes - biochemistry helps to explain physiological processes, and develop new drugs and methods for treating diseases

2. Organic Versus Inorganic Organic molecules • contain C and H • usually larger than inorganic molecules • dissolve in water and organic liquids • carbohydrates, proteins, lipids, and nucleic acids Inorganic molecules • generally do not contain C • usually smaller than organic molecules • usually dissociate in water, forming ions • water, oxygen, carbon dioxide, and inorganic salts

3. Inorganic Substances Water • most abundant compound in living material • two-thirds of the weight of an adult human • major component of all body fluids • medium for most metabolic reactions • important role in transporting chemicals in the body • absorbs and transports heat Oxygen (O2) • used by organelles to release energy from nutrients in order to drive cell’s metabolic activities • used with glucose to make ATP

4. Inorganic Substances Carbon dioxide (CO2) • waste product released during metabolic reactions • must be removed from the body Inorganic salts • abundant in body fluids • sources of necessary ions (Na+, Cl-, K+, Ca2+, etc.) • play important roles in metabolism

5. Organic SubstancesCarbohydrates • provide energy to cells • supply materials to build cell structures • water-soluble • contain C, H, and O • ratio of H to O close to 2:1 (C6H12O6) • monosaccharides – glucose, fructose • disaccharides – sucrose, lactose • polysaccharides – glycogen, cellulose

6. Organic SubstancesCarbohydrates

7. Organic SubstancesLipids • soluble in organic solvents; insoluble in water • fats (triglycerides) • used primarily for energy; most common lipid in the body • contain C, H, and O but less O than carbohydrates (C57H110O6) • building blocks are 1 glycerol and 3 fatty acids per molecule • saturated and unsaturated

8. Types of Fat

9. Saturated fat • Contain the maximum number of H atoms • Tend to be solids at room temp • Comes from animals • Unhealthy fat

10. Unsaturated fats • Not fully saturated with hydrogen • Tend to be liquid at room temperature • Come from plants • Healthy fats

11. Trans (hydrogenated) Fat

12. Organic SubstancesLipids • phospholipids • building blocks are 1 glycerol, 2 fatty acids, and 1 phosphate per molecule • hydrophilic and hydrophobic • major component of cell membranes 2-25

13. Organic Substances Lipids • steroids • four connected rings of carbon • widely distributed in the body, various functions • component of cell membrane • used to synthesize hormones • cholesterol

14. Nutrition Label

15. Organic SubstancesProteins • structural material • energy source • hormones • receptors • enzymes • antibodies • amino acids held together with peptide bonds • building blocks are amino acids 2-27

16. Organic Substances Proteins Four Levels of Structure

17. Organic SubstancesNucleic Acids • carry genes • encode amino acid sequences of proteins • building blocks are nucleotides • DNA (deoxyribonucleic acid) – double polynucleotide • RNA (ribonucleic acid) – single polynucleotide

18. Organic SubstancesNucleic Acids

19. NUCLEIC ACIDS • DNA and RNA are the 2 types • DNA comprises genes, all hereditary info, the instructions for making proteins and RNA • RNA controls protein synthesis (putting amino acids together to form polypeptides)

20. Nucleic acids are made of nucleotides • Nucleotides consist of a 5 Carbon sugar, phosphate group(s), and a N base  • DNA – sugar is deoxyribose, 2 strands twisted into a double helix, N base pairing is A-T and C –G  • RNA – sugar is ribose, single strand, has the base uracil instead of thymine