Comprehensive Notes on Macromolecules: Carbohydrates

Macromolecules: Intro and Carbohydrates

The Molecules of Life

• Organic compounds, carbon compounds, biomolecules are key to life.

The Fantastic Four

• Four major classes of organic macromolecules:
  • Nucleic Acids
  • Carbohydrates
  • Lipids
  • Proteins
• Monomers associated with each:
  • Nucleotide (Nucleic Acid)
  • Monosaccharide (Carbohydrate)
  • Glycerol and Fatty Acids (Lipid)
  • Amino Acid (Protein)

Organic Building Blocks

• Essential atoms for living things:
  • Carbon (C)
  • Hydrogen (H)
  • Oxygen (O)
  • Nitrogen (N)
  • Sulfur (S)
  • Phosphorus (P)
• These elements form:
  • Hydrocarbons
  • Carbohydrates & Lipids
  • Amino acids & proteins
  • Nucleic acids, RNA, & DNA
  • Single atoms of iron, copper, magnesium for some proteins

The Power of Carbon!

• Carbon has 4 valence electrons, enabling it to form diverse structures. Carbon atoms bond to other carbon atoms.

Monomer vs. Polymer

• Smaller Organic Molecule: Monomer
• Macromolecule: Polymer
• Polymerization requires the formation of covalent bonds.

Different Types of Chemical Bonds

• Covalent Bonding: Atoms share electrons.
• Ionic Bonding: Electrons are transferred (e.g., from Na to Cl).
• Metallic Bonding: Ions surrounded by free electrons.
• Molecular Bonding: Weak electrical attraction binds molecules.

4 Types of Biological Macromolecules

1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic Acids (DNA & RNA)

Main Characteristics

Carbohydrates

• General formula: C(H2O)n

Why Do We Need Carbs?

• (This question is posed, implying carbohydrates are essential)

How are Carbohydrates Classified?

• Simple Carbohydrates:
  • Monosaccharides: Glucose, Fructose, Galactose
  • Disaccharides: Maltose, Lactose, Sucrose
• Complex Carbohydrates:
  • Polysaccharides: Starches, Fibers, Glycogen

From Monomer to Polymer (Dehydration Synthesis)

• Dehydration synthesis involves removing water to form a bond.
• Glycosidic bond: A type of covalent bond (STRONG!) that links monosaccharides.

Disaccharides (are polymers!)

• Sucrose (Glucose-Fructose)
• Lactose (Galactose-Glucose)
• Maltose (Glucose-Glucose)
• Formula: C{12}H{22}O_{11}, because water is removed during bond formation.

From Polymer to Monomer (Hydrolysis)

• Hydrolysis uses water to break the bond between monomers.

Polysaccharides

• Starch: How plants store glucose; Moderately branched.
• Glycogen: How animals store glucose; Highly branched.
• Cellulose: Makes up cell walls in plants.

What is the Function of Carbohydrates?

• Energy source!
• Energy storage (animals and plants) - Glycogen/Starch
• Cell walls (plants) - Cellulose
• Protection (insects/fungus) - Chitin

Where Does the Energy Come From?

• The bonds!

Application: How Do We Know the Presence of Carbohydrates?

• Through various tests.

Test for Starch

• Iodine Test: Determines the presence of starch in a food item. Iodine solution is used.

Iodine Test Results (Examples)

• Starch + Iodine

Benedict’s Test

• Detects simple sugars (glucose, fructose, galactose).

Benedict’s Test Explanation

• Benedict’s reagent changes color upon heating, indicating sugar quantity.
• Blue: no simple sugar
• Red: high amount of simple sugar

Quick Summary

• Carbohydrates described briefly.

Next Class

• Bring a packaged snack with a label.
• Nutrition facts are reviewed

Homework

• Complete the carbohydrate review sheet using the presentation and online research.
• Quizlet for carbohydrate vocabulary.

Exploring 3D Models (Optional)

• Explore 3D configurations of carbohydrates like glucose, fructose, ribose, sucrose, cellulose.

Interested in Learning More? (Optional)

• Bozeman Science video tutorial resource.