Cowan_MicrobiologyCh2

Chapter Overview

• Title: The Chemistry of Biology

• Authors: Marjorie Kelly Cowan, Heidi Smith

• Edition: Seventh

• Publisher: McGraw Hill LLC

Learning Outcomes

• Identify the four main families of biochemicals.

• Provide examples of cell components made from these families.

• Differentiate protein structure levels: primary, secondary, tertiary, quaternary.

• List components of nucleotides and ATP.

• Name nitrogen bases in DNA and RNA.

Key Families of Biochemicals

1. Carbohydrates

• Definition: Biological molecules consisting of carbon, hydrogen, and oxygen.

• Examples: Sugars, starches, cellulose.

2. Lipids

• Definition: Diverse group of hydrophobic molecules.

• Examples: Fats, oils, phospholipids, waxes, steroids.

3. Proteins

• Definition: Polymers of amino acids that perform various functions.

• Roles: Structural support, transport, enzymes, antibodies.

4. Nucleic Acids

• Definition: Polymers of nucleotides that encode genetic information.

• Examples: DNA, RNA.

In-Depth Focus on Macromolecules

Macromolecular Structures

• Assembled from: Smaller molecular subunits (monomers).

• Formation process: Polymerization - binding of monomers into polymers.

• Functions:

  • Structural components

  • Molecular messengers

  • Energy sources

  • Enzymes (biochemical catalysts)

  • Nutrient stores

  • Genetic information sources

Carbohydrates: Structure and Function

Monosaccharides

• Definition: Simple sugars (3-7 carbons).

• Examples: Glucose, fructose.

Disaccharides

• Definition: Formed from two monosaccharides.

• Examples:

  • Maltose (glucose + glucose)

  • Lactose (glucose + galactose)

  • Sucrose (glucose + fructose)

Polysaccharides

• Definition: Long chains of monosaccharides.

• Examples: Starch, cellulose, glycogen.

Lipids: Types and Functions

Types of Lipids

• Triglycerides: Composed of glycerol and three fatty acids, serve as energy storage.

• Phospholipids: Form cell membranes with hydrophilic heads and hydrophobic tails.

• Steroids: Four-ring structure, includes cholesterol and hormones.

• Waxes: Long-chain fatty acids, protective functions.

Proteins: Structure and Function

Amino Acids

• Building blocks of proteins, 22 different forms.

• Structure: Includes an amino group, carboxyl group, hydrogen, and R group.

Protein Structure Levels

1. Primary Structure: Sequence of amino acids.

2. Secondary Structure: Coiling (α-helix) or folding (β-pleated sheet).

3. Tertiary Structure: Overall 3D shape from interactions between R groups.

4. Quaternary Structure: Complexes formed by more than one polypeptide chain.

Nucleic Acids: DNA & RNA

DNA (Deoxyribonucleic Acid)

• Structure: Double helix; contains deoxyribose and thymine.

• Function: Genetic material, heredity information storage.

RNA (Ribonucleic Acid)

• Structure: Single-stranded; contains ribose and uracil.

• Function: Protein synthesis, gene expression.

ATP (Adenosine Triphosphate)

• Components: Adenine, ribose, three phosphates.

• Function: Energy currency in cells, releases energy when phosphate bonds break.

Cells: The Fundamental Unit of Life

• Definition: Basic structural and functional unit; aggregates of various biomolecules.

• Characteristics: Diverse structures, contain DNA, and ribosomes for protein synthesis.

Eukaryotic vs. Prokaryotic Cells

• Eukaryotes: Contain a nucleus and organelles; include plants, animals, fungi.

• Prokaryotes: Lack a nucleus and organelles; include bacteria and archaea.