Macromolecules and Their Functions

Macromolecules

• Four major macromolecules: proteins, carbohydrates, lipids, and nucleic acids
• Organic molecules are typically composed of carbon atoms with other atoms (like hydrogen, oxygen, and nitrogen) attached.
• Monomers are small molecules that bond to form larger polymers.

Monomers

• Four main types of monomers: sugars, amino acids, fatty acids, and nucleotides.

Polymers

• Polymers are large molecules formed by the chemical bonding of monomers.

Dehydration Synthesis & Hydrolysis

• Dehydration synthesis joins molecules by removing water.
• Hydrolysis breaks molecules apart using water.

Carbohydrates

• Carbohydrates are organic compounds (like sugars and starches)
• Elements: carbon, hydrogen, and oxygen (CHO)
• Function: energy storage
• Monomers: monosaccharides (e.g., glucose, fructose)
• Polymers: starch, glycogen, cellulose, and chitin
• Functions of carbohydrate polymers:
  • Starch: energy storage in plants
  • Glycogen: energy storage in animals
  • Cellulose: structural support in plant cell walls
  • Chitin: structural support in arthropod exoskeletons and fungal cell walls

Lipids

• Lipids are fatty, waxy, or oily compounds soluble in organic solvents but insoluble in water.
• Elements: carbon, hydrogen, and oxygen (CHO)
• Monomers: glycerol and fatty acids
• Structures:
  • Triglycerides: glycerol + 3 fatty acids, store energy.
  • Phospholipids: glycerol + 2 fatty acids + phosphate group, cell membrane barrier.
  • Cholesterol: four connected carbon rings, short tail, and hydroxyl group, cell membrane component, hormone precursor.

Proteins

• Monomers: amino acids
• Amino acids are organic molecules building blocks of proteins.
• Polymers: polypeptides, long chains of amino acids linked by peptide bonds.
• Functions: structural support, regulate gene expression, transport molecules (e.g., oxygen), and defend against disease (e.g., antibodies).
• Enzyme structure: specific three-dimensional shapes.
  • Enzymes are proteins that catalyze chemical reactions.
  • Denatured enzyme: loses its structure and function due to heat or chemicals.
  • Lock and Key v. Induced Fit: models describing enzyme-substrate interaction; Lock and Key is strict fit, Induced Fit is flexible fit.
  • Enzyme-substrate complex: temporary combination of enzyme and substrate during a reaction.

Nucleic Acids

• Monomers: nitrogen-containing base, sugar (ribose or deoxyribose), and phosphate group.
• DNA: carries genetic information, double helix structure (adenine pairs with thymine, guanine pairs with cytosine).
• RNA: carries genetic information from DNA to ribosomes, single-stranded structure, (adenine pairs with uracil).

Cell Theory

• All living things are composed of one or more cells.
• The cell is the basic unit of structure and function in living things.
• All cells come from pre-existing cells.
• Contributors: Robert Hooke, Antonie van Leeuwenhoek, Matthias Schleiden, Theodor Schwann, Rudolf Virchow.
• Organelles found in all cells: Ribosomes (protein synthesis).

Cell Organelles (Specific to cell types)

• Bacteria: plasmids
• Animal: lysosomes
• Plant: chloroplasts, large central vacuoles

Further Organelle functions (missing from the original text)

• Endoplasmic Reticulum (ER): involved in protein synthesis and lipid metabolism.
• Golgi Apparatus: modifies, sorts, and packages proteins.
• Nucleus: controls cell activities, contains DNA.
• Lysosomes: break down waste materials using enzymes.
• Ribosomes (function): synthesize proteins.