Macromolecules Overview

Macromolecules Overview

Macromolecules are large molecules essential for life, consisting of repeating units called monomers that join to form polymers. There are four main types of macromolecules: carbohydrates, proteins, lipids, and nucleic acids. Each has a unique structure and function in biological systems.

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1. Carbohydrates

• Monomer: Monosaccharide (e.g., glucose)
• Polymer: Polysaccharides (e.g., starch, cellulose)
• Elements: Carbon, Hydrogen, Oxygen
• Structure: Typically in a 1:2:1 ratio (C$_n$H$_2n$O$_n$), with ring structures like C$_6$H$_{12}$O$_6$
• Function: Provide short-term energy, store energy, and offer structural support (e.g., cellulose in plants, chitin in insect exoskeletons)

2. Proteins

• Monomer: Amino acids
• Polymer: Polypeptides (proteins)
• Elements: Carbon, Hydrogen, Oxygen, Nitrogen (sometimes sulfur)
• Structure: Complex folding patterns that create specific shapes necessary for function
• Function: Build and repair tissues, act as enzymes to speed up reactions, and perform structural and regulatory roles (e.g., enzymes, hemoglobin for oxygen transport)

3. Lipids

• Monomer: Glycerol and fatty acids
• Polymer: Triglycerides, phospholipids
• Elements: Carbon, Hydrogen, Oxygen (phosphorus in phospholipids)
• Structure: Long hydrocarbon chains or rings; phospholipids have a glycerol backbone with two fatty acid tails and a phosphate group
• Function: Store energy long-term, form cell membranes, and serve as signaling molecules (e.g., fats, oils, phospholipids in cell membranes)

4. Nucleic Acids

• Monomer: Nucleotide
• Polymer: DNA and RNA
• Elements: Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus
• Structure: DNA has a double helix, while RNA is usually single-stranded; both contain a phosphate group, sugar, and nitrogenous base
• Function: Store and transmit genetic information, guide protein synthesis, and enable inheritance (e.g., DNA encodes traits)

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Key Processes

1. Dehydration Synthesis: Monomers join to form polymers, releasing water as a byproduct. This process builds macromolecules.
2. Hydrolysis: Polymers are broken down into monomers by adding water, releasing energy.

Enzymes and Catalysis

• Enzymes are proteins that act as catalysts, speeding up reactions by lowering the activation energy. They bind specific substrates at an active site and facilitate the reaction without being consumed.
• Factors Affecting Enzymes: Temperature, pH, and salinity can cause enzymes to denature (lose their shape and function).

Each macromolecule plays a vital role in biological systems, supporting structure, function, storage, and transmission of genetic material.