Lecture Overview: Macromolecules & Cell Biology

Introduction

This study guide covers the foundational concepts of macromolecules in biology, focusing on carbon-based molecules, carbohydrates, and lipids. It also introduces cell composition and the importance of chemical groups in organic molecules.

Cell Biology

Purpose and Scope

• Understanding life at the cellular level.

• Exploring disease mechanisms.

• Discovering new medical therapies.

Cell Composition

Major Components

• Water: Constitutes 70–95% of cell mass.

• Carbon-based compounds: Make up the rest of the cell, including carbohydrates, lipids, proteins, and DNA.

• Carbon atoms form the backbone of biological molecules, often bonded to hydrogen, oxygen, nitrogen, phosphorus, and sulfur.

Carbon Atoms

Properties and Importance

• Valence electrons: Carbon has 4 valence electrons, allowing it to form up to 4 covalent bonds.

• Versatility in bonding enables the formation of a wide variety of molecules essential for life.

• Carbon skeletons are the framework for organic molecules.

Molecular Diversity of Carbon Compounds

Structural Variations

• Carbon chains can vary in length, branching, double bond position, and ring structure.

• Examples:

  • Length: Ethane, Propane

  • Branching: Butane, 2-methylpropane (isobutane)

  • Double bond position: 1-butene, 2-butene

  • Presence of rings: Cyclohexane, Benzene

Chemical Groups: The Spice of Hydrocarbons

Functional Groups and Their Roles

• Functional groups are specific groups of atoms within molecules that confer distinct chemical properties.

• They are directly involved in chemical reactions and biological processes.

• Functional groups can replace one or more hydrogens in a hydrocarbon.

Major Functional Groups

Nomenclature and Key Terms

Essential Vocabulary

• Carbohydrates: Sugars and polymers of sugars.

• Lipids: Hydrophobic molecules including fats, phospholipids, and steroids.

• Proteins: Polymers of amino acids with diverse functions.

• DNA: Carrier of genetic information.

• Polymer: Large molecule made of repeating subunits.

• Monosaccharides: Simple sugars (e.g., glucose).

• Disaccharides: Two monosaccharides joined (e.g., sucrose).

• Polysaccharides: Long chains of monosaccharides (e.g., starch, cellulose).

• Saturated and Unsaturated Fats: Types of fatty acids differing in hydrogen content and double bonds.

Learning Outcomes

Objectives for Study

• Illustrate and recognize the molecular diversity of carbon-based compounds.

• Identify and describe functional groups and their characteristics.

• Define and distinguish polymers and explain their synthesis.

• Describe carbohydrate structures and functions.

• Explain fat structures and functions, including differences between saturated, unsaturated, hydrogenated, and trans fats.

• Compare the structures and functional differences of major macromolecules.

Epigenetics and Research Context

Role in Memory and Addiction

• Epigenetic mechanisms regulate gene expression without altering DNA sequence.

• Influence memory formation in young and aging brains.

• Play a role in addiction through changes in gene expression.

• Interaction between genome, environment, and epigenome shapes the phenotype.

Summary Table: Major Macromolecules

Key Equations

Covalent Bond Formation

Carbon forms up to four covalent bonds:

General Formula for Carbohydrates

Fatty Acid Saturation

Saturated: No double bonds Unsaturated: One or more double bonds

Additional info:

• Functional groups are crucial for the reactivity and interaction of biomolecules.

• Epigenetic regulation is a growing field in neurobiology and disease research.