Macromolecules Overview

Macromolecules

• Macromolecules are large carbon compounds built from smaller units called monomers.
• This process of joining monomers is similar to linking a railroad train's cars.
• Monomers can bind together to create complex molecules called polymers (poly= many).
• Polymers are made up of repeating, linked units.
• Macromolecules are formed by the linking together of these large polymers.
• Macromolecules are composed of smaller subunits, which are linked together through condensation reactions or dehydration synthesis.
• During these reactions, water molecules are released as a byproduct.

Types of Macromolecules

• Four main types: Carbohydrates, Lipids, Proteins, and Nucleic Acids.

Carbohydrates

• Composed of carbon, hydrogen, and oxygen atoms in a 1:2:1 ratio.
• General formula: (CH₂O)ₙ, where n represents the number of carbons.
• Examples of monosaccharides (simple sugars): Glucose, Fructose, Galactose -Glucose : commonly found in blood of animals. -Galactose : a simple sugar found in milk. -Fructose : commonly found in fruit.
• Glucose and fructose have the formula C₆H₁₂O₆ but different structures making them isomers.
• Examples of disaccharides (two monosaccharides joined): Lactose (milk sugar) and Sucrose (table sugar). -Lactose: composed of Galactose and Glucose. -Sucrose: composed of Fructose and Glucose.
• Examples of polysaccharides (many monosaccharides joined): Starch (plant storage), Cellulose (plant cell walls), Glycogen (animal storage). Starch is used as a storage form of glucose in plants, cellulose provides strength and rigidity in plant cell walls, and glycogen is the animal storage form of glucose used as quick energy.

Lipids

• Class of macromolecules that do not dissolve in water.
• Common types include fats, oils, and waxes.
• Lipids usually serve one of three main functions: energy storage, structural support in cell membranes (phospholipids), and serving as reactants for metabolic reactions.
• Fatty acids are the building blocks of lipids. -These fatty acids are classified as either saturated or unsaturated, depending on the presence of double bonds in their carbon chain.
  • Saturated fatty acids have the maximum number of hydrogen atoms possible and are usually solid at room temperature. Commonly from animal products
  • Unsaturated fatty acids have double bonds and are usually liquid at room temperature. Often found from plant oils.
• Triglycerides are a common lipid, composed of glycerol linked to three fatty acids via dehydration synthesis reaction.

Proteins

• Composed mainly of carbon, hydrogen, and nitrogen atoms.
• Proteins are crucial for constructing body parts such as hair, skin, nails, and blood.
• Amino acids are the building blocks of proteins.
• There are 20 different types of amino acids that are essential.
• Enzymes are a type of protein that acts as catalysts, speeding up chemical reactions by lowering activation energy.

Nucleic Acids

• Complex organic molecules that store genetic information.
• Nucleotides are the building blocks of nucleic acids.
• Each nucleotide consists of a phosphate group, a sugar (deoxyribose in DNA, ribose in RNA), and a nitrogenous base.
• Three main types of nucleic acids:
  • DNA (deoxyribonucleic acid): stores genetic information within the cell nucleus.
  • RNA (ribonucleic acid): involved in protein synthesis, carrying instructions from DNA to the ribosomes.
  • ATP (adenosine triphosphate): a nucleotide containing three phosphate groups is used as energy for the cell.

Hydrolysis and Dehydration Synthesis

• Monomers link together to form polymers through a reaction called dehydration synthesis (or condensation reaction).
• Water (H₂O) is released as a by-product during dehydration synthesis.
• The breakdown of polymers occurs through hydrolysis.
• In hydrolysis, water is added to break down the bonds between monomers.