Notes on Carbon and Macromolecules

Elements of Life

Unit I - Topic 2 Notes

Overview

• Theme: Exploration of carbon in organic chemistry and its significance in biological macromolecules.

Carbon in Organic Chemistry

• Organic Chemistry: The study of compounds with covalently bonded carbon.

• Organic Compounds: Compounds that contain carbon and hydrogen.

• Valence Electrons: Carbon has 4 valence electrons.

Carbon Bonding and Structure

• Covalent Bonds:

  • Carbon can form single, double, or triple covalent bonds.

  • A single carbon can form up to four covalent bonds, allowing it to create long chains.

  • Commonly forms bonds with hydrogen, oxygen, and nitrogen.

• Covalent Bonds Impact:

  • The type and number of covalent bonds carbon forms with other atoms affect the length of the carbon chain and the shape of the molecule.

Carbon Chains

• Formation: Carbon can use its valence electrons to form covalent bonds with other carbons, creating a chain.

• Hydrocarbons: Organic molecules consisting only of carbon and hydrogen; serve as a framework for more complex organic molecules.

• Skeleton Variability:

  • Carbon chains form the skeletons of most organic molecules.

  • Variability includes:

  • Length of the chain

  • Branching of the chain

  • Position of double bonds

  • Presence of rings.

  • Many regions of a cell's organic molecules contain hydrocarbons.

Functional Groups

• Functional Groups: Chemical groups attached to the carbon skeleton that participate in chemical reactions.

Introduction to Biological Macromolecules

Unit I - Topic 3 Notes

Molecular Diversity

• Carbon Variability: Variations in carbon skeletons contribute to molecular diversity.

• Macromolecules: Large molecules made of smaller subunits (monomers).

  • Four classes of macromolecules include:

    • Carbohydrates

    • Proteins

    • Nucleic acids

    • Lipids

  • Note: Includes polymers that are hydrophobic molecules.

  • Other important elements:

  • Nitrogen: Important for building proteins and nucleic acids.

  • Phosphorus: Important for building nucleic acids and some lipids.

Formation and Breakdown of Macromolecules

• Polymers: Chain-like macromolecules made of similar or identical repeating units covalently bonded together.

• Monomers: The repeating units that comprise polymers.

Reactions Involving Macromolecules

• Dehydration Reaction:

  • This reaction bonds two monomers with the loss of water ( ext{H}_2 ext{O}).

  • Reaction format:

  • $A + B <br>ightarrow AB + H_2O$

  • Explanation:

  • The -OH of one monomer bonds to the -H of another monomer, resulting in the release of water.

• Visual Representation:

  • Example of Dehydration Reaction:

  • Starting with two monomers:

    • Glucose (C6H12O6)

    • Fructose (C6H12O6)

  • Connected to form Sucrose with the release of water.

• Hydrolysis:

  • A process that breaks the bonds in a polymer by adding water ( ext{H}_2 ext{O}).

  • Reaction format:

  • $AB + H_2O <br>ightarrow A + B$

  • Explanation:

  • One -H of H2O bonds to one monomer and the remaining -OH of H2O attaches to the other monomer.

• Visual Representation:

  • Example of Hydrolysis:

  • Starting with Sucrose

  • Broken into Glucose and Fructose by adding water.

Concept Check Questions

1. Hydrolysis Reaction with Amylose Starch:

   • Problem: If amylose starch consists of 300 glucose monomers, how many water molecules are needed to fully hydrolyze it?

   • Answer: 299 water molecules needed.

2. Properties of Carbon: Describe essential properties of carbon that make it crucial for life.

3. Silicon Comparison: Analyze silicon's position on the periodic table relative to carbon and its implications for silicon's role in biological systems.