Part ONE

PRINCIPLES OF MOLECULAR STRUCTURE AND

FUNCTION 1

Chapter 1

INTRODUCTION TO BIOMOLECULES

Water Is the Solvent of Life

Water Contains Hydronium Ions and Hydroxyl Ions

Ionizable Groups Are Characterized by Their pK Values

The Blood pH is Tightly Regulated

Acidosis and Alkalosis Are Common in Clinical Practice

Bonds Are Formed by Reactions between Functional Groups

Isomeric Forms Are Common in Biomolecules

Properties of Biomolecules Are Determined by Their Noncovalent

Interactions

Triglycerides Consist of Fatty Acids and Glycerol

Monosaccharides Are Polyalcohols with a Keto Group or an

Aldehyde Group

Monosaccharides Form Ring Structures

Complex Carbohydrates Are Formed by Glycosidic Bonds

Polypeptides Are Formed from Amino Acids

Nucleic Acids Are Formed from Nucleotides

Most Biomolecules Are Polymers

Summary

Chapter 2

INTRODUCTION TO PROTEIN STRUCTURE

Amino Acids Are Zwitterions

Amino Acid Side Chains Form Many Noncovalent

Interactions

Peptide Bonds and Disulfide Bonds Form the Primary Structure of

Proteins

Proteins Can Fold Themselves into Many Shapes

-Helix and beta-Pleated Sheet Are the Most Common Secondary

Structures in Proteins

Globular Proteins Have a Hydrophobic Core

Proteins Lose Their Biological Activities When Their Higher-Order

Structure Is Destroyed

The Solubility of Proteins Depends on pH and Salt

Concentration

Proteins Absorb Ultraviolet Radiation

Proteins Can Be Separated by Their Charge or Their Molecular

Weight

Abnormal Protein Aggregates Can Cause Disease

Neurodegenerative Diseases Are Caused by Protein Aggregates

Protein Misfolding Can Be Contagious

Summary

Chapter 3

OXYGEN TRANSPORTERS: HEMOGLOBIN AND

MYOGLOBIN

The Heme Group Is the Oxygen-Binding Site of Hemoglobin and

Myoglobin

Myoglobin Is a Tightly Packed Globular Protein

Red Blood Cells Are Specialized for Oxygen Transport

The Hemoglobins Are Tetrameric Proteins

Oxygenated and Deoxygenated Hemoglobin Have Different

Quaternary Structures

Oxygen Binding to Hemoglobin Is Cooperative

2,3-Bisphosphoglycerate Is a Negative Allosteric Effector of

Oxygen Binding to Hemoglobin

Fetal Hemoglobin Has a Higher Oxygen-Binding Affinity than

Does Adult Hemoglobin

The Bohr Effect Facilitates Oxygen Delivery

Most Carbon Dioxide Is Transported as Bicarbonate

Summary 38

Chapter 4

ENZYMATIC REACTIONS 39

The Equilibrium Constant Describes the Equilibrium of the

Reaction

The Free Energy Change Is the Driving Force for Chemical

Reactions

The Standard Free Energy Change Determines the Equilibrium

Enzymes Are Both Powerful and Selective

The Substrate Must Bind to Its Enzyme before the Reaction Can

Proceed

Rate Constants Are Useful for Describing Reaction Rates

Enzymes Decrease the Free Energy of Activation

Many Enzymatic Reactions Can Be Described by Michaelis-Menten

Kinetics

K m and V max Can Be Determined Graphically

Substrate Half-Life Can Be Determined for First-Order but Not

Zero-Order Reactions

K cat/ K m Predicts the Enzyme Activity at Low Substrate

Concentration

Allosteric Enzymes Do Not Conform to Michaelis-Menten

Kinetics

Enzyme Activity Depends on Temperature and pH

Different Types of Reversible Enzyme Inhibition Can Be

Distinguished Kinetically

Enzymes Stabilize the Transition State

Chymotrypsin Forms a Transient Covalent Bond during

Catalysis

Summary

Chapter 5

COENZYMES

Enzymes Are Classified According to Their Reaction Type

Adenosine Triphosphate Has Two Energy-Rich Bonds

ATP Is the Phosphate Donor in Phosphorylation Reactions

ATP Hydrolysis Drives Endergonic Reactions

Cells Always Try to Maintain a High Energy Charge

Dehydrogenase Reactions Require Specialized Coenzymes

Coenzyme A Activates Organic Acids

S-Adenosyl Methionine Donates Methyl Groups

Many Enzymes