Human Anatomy and Physiology I The Chemical Basis of Life Organic Compounds Instructor: Mary Holman

Inorganic Compounds Usually smaller than organic molecules Generally do not contain C* Usually smaller than organic molecules Usually dissociate in water, forming ions Water, oxygen, carbon dioxide, and inorganic salts * exceptions: CO, CO2, HCO3

Important Inorganic Compounds Water (H2O) 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 Necessary for survival

Important Inorganic Compounds 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

Organic Compounds Contain C and H Usually larger than inorganic molecules Dissolve in water or organic liquids Carbohydrates, lipids, proteins, nucleic acids, and adenosine triphosphate

Terminology used in describing units of organic compounds monomer mono- “one unit” dimer di- “two units” trimer tri- “three units” polymer poly- “many units”

Important Organic Compounds Carbohydrates 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) Building blocks (monomers) of carbohydrates are monosaccharides (like glucose & fructose) and disaccharides (like sucrose and lactose) Glycogen,and cellulose are examples of polysaccharides Note: ending in “ose”

H O C H C O H H O C H H C O H H C O H H C O H H Glucose (C6H12O6) Fig. 2.11a Glucose (C6H12O6) H O C H C O H H O C H H C O H H C O H H C O H H Some glucose molecules have a straight chain of carbon atoms. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

More commonly, glucose molecules form a ring structure. Fig 2.11b Glucose (C6H12O6) H H C O H C O H H H C C O H H O O H C C H O H More commonly, glucose molecules form a ring structure. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

This shape symbolizes the ring structure of a Fig 2.11c Fig. 2.11c O This shape symbolizes the ring structure of a glucose molecule. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Monosaccharide Fig. 2.12a O Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Fig. 2.12b Disaccharide O O O Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Fig. 2.12c Polysaccharide O O O O O O CH2 O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O CH2 O O O O O O O O O Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Important Organic Compounds Lipids 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 Can be saturated and unsaturated Phospholipids Steroids

Saturated fatty acid Fig. 2.13a H H H H H H H H H H H H H H H O H O C Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Unsaturated fatty acid Fig. 2.13b Unsaturated fatty acid H H H H H H H H H H O H H O C C C C C C C C C C C C H H H H H H H H Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

A Fat Molecule - Triglyceride Fig. 2.14 A Fat Molecule - Triglyceride H O H H H H H H H H H H H H H H H H C O C C C C C C C C C C C C C C C C H H H H H H H H H H H H H H H H O H H H H H H H H H H H H H H H H H H C O C C C C C C C C C C C C C C C C C C H H H H H H H H H H H H H H H H H H O H H H H H H H H H H H H H H C O C C C C C C C C C C C C C C H H H H H H H H H H H H H Glycerol portion Fatty acid portions Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

A Fat Molecule - Triglyceride Fig. 2.15a A Fat Molecule - Triglyceride H H C O Fatty acid H C O Fatty acid H C O Fatty acid H Glycerol portion Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

A Phospholipid Molecule Fig. 2.15b H H C O Fatty acid H C O Fatty acid O H H H H C O P O C C N H O – H H H Phosphate portion (the unshaded portion may vary) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

of a phospholipid molecule Fig. 2.15c Schematic representation of a phospholipid molecule Water-insoluble (hydrophobic) “tail” Water-soluble (hydrophilic) “head” Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Fig. 2.16a General structure of a steroid Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Important Organic Compounds Proteins More complex than carbohydrates and lipids Have a larger range of functions : structural material, energy source, hormones, receptors, enzymes, antibodies Contain N as well as C, H, and O and some contain S Amino acids are the building blocks (monomers) of proteins There are twenty (20) different amino acids Amino acids bind together by forming peptide bonds

General structure of an amino acid Fig. 2.17a H N C C OH H H O The portion common to all amino acids is within the oval. It includes the amino group (—NH2) and the carboxyl group (—COOH). The "R" group, or the "rest of the molecule," is what makes each amino acid unique. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Fig. 2.17b H C H C C H H H C C H S C H C H H C H H N C C OH H N C C OH (b) Cysteine. Cysteine has an R group that contains sulfur. Phenylalanine. Phenylalanine has a complex R group. Improper metabolism of phenylalanine occurs in the disease phenylketonuria. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

A Peptide Bond H O R O H N C C N C C OH H R H H Fig. 2.18 (H2O) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Primary Structure of Proteins Fig. 2.19a Amino acids Polypeptide chain Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Secondary Structure of Proteins Fig. 2.19b Secondary Structure of Proteins C C R H H H H N C O C C N R C O H N H O C H H H H C C H R R R N C N H O C N C C R O C O C N H O H R R H H R C C H C H H N C H N C O C N O H R C O H N O C H H H H H C C R R R N C N C N H O C R C O C H O C N H H O R R H R C C C H N C H H C N H N C O O H C O H N O H H C C Coiled structure Pleated structure Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Tertiary Structure of Proteins Fig. 2.19c Tertiary Structure of Proteins Three-dimensional folding Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Quaternary Structure of Proteins Fig. 2.19d Two or more folded chains may connect together Hemoglobin molecule Polypeptide chain b2 Polypeptide chain b1 Fig. 14.9a Polypeptide chain a2 Polypeptide chain a1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Important Organic Compounds Nucleic Acids Huge molecules that contain C, H, O, N and P Building blocks (monomers ) are nucleotides Nucleic acids are of two varieties Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA)

Basic Structure of a Nucleotide Fig. 2.20 P Base Sugar Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Difference between sugar groups of DNA and RNA Fig. 2.22 O O HOCH OH HOCH OH 2 2 C C C C H H H H H H H H C C C C OH H Ribose Deoxyribose Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

RNA DNA Fig. 2.21 S P B P B B P S S S P P B B B P S S S P B P B B P S Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Important Organic Compounds Adenosine triphosphate - ATP Energy currency of living systems ATP stores energy in the form of 3 phosphate groups When a phosphate group is removed from ATP, energy is liberated and the molecule is called ADP