Biology: Major Categories of Biomolecules

Major Categories of Biomolecules

• Four primary categories: Carbohydrates, Lipids, Proteins, Nucleic Acids.

Monomers and Polymers

• Biomolecules are made of monomers (small molecules) and polymers (chains of bonded monomers).
• Dehydration synthesis removes water, allowing molecules to bond.
• Hydrolysis synthesis adds water to separate bonded molecules.

Carbohydrates

• Chemical formula: CnH2nOn.
• Provide energy and contain water (H2O) for each carbon atom.
• Types include:
  • Monosaccharides: Simple sugars (e.g., glucose, galactose, fructose) that can be isomers.
  • Disaccharides: Formed from two monosaccharides (e.g., lactose, sucrose, maltose) via glycosidic bonds.
  • Polysaccharides: Complex carbohydrates made of linked monosaccharides (e.g., cellulose, glycogen, starch, chitin).

Carbohydrates: Food Sources

• Simple Carbs: Found in candy, fruits, and sweet drinks, providing quick energy.
• Complex Carbs: Found in pasta and legumes, digestion takes longer.

Lipids

• Insoluble in water, characterized by diverse structures and made with ester bonds.

Functions of Lipids

• Fats/Triglycerides: Energy storage, insulation, and cushioning for organs.
• Saturated Fats: Solid at room temperature, high melting point (e.g., coconut oil).
• Unsaturated Fats:
  • Monounsaturated: One double bond, liquid (e.g., olive oil).
  • Polyunsaturated: Multiple double bonds, liquid (e.g., sunflower oil).
• Trans Fats: Partially hydrogenated, high melting point, often used in industrial applications.
• Phospholipids: Major component of cell membranes with hydrophilic head and hydrophobic tails.
• Steroids: Structure of four carbon rings; function in membrane fluidity and signaling (e.g., cholesterol).

Proteins

• Composed of carbon, hydrogen, oxygen, and nitrogen; over 30,000 types exist.
• Amino acids are the building blocks, differing by side chains (R groups).
• Essential Amino Acids (9 in diet); Non-Essential can be synthesized by the body.

Protein Functions

• Structural: Keratin, collagen, muscle proteins.
• Hormonal: Insulin and cyclins act as messengers in the body.
• Transport: Hemoglobin carries oxygen.

Denaturation

• Proteins can be altered irreversibly by heat, acids, bases, or alcohol.

Nucleic Acids

• Store hereditary information and are composed of nucleotides.
• Types include:
  • Nucleoside: Base plus sugar.
  • Nucleotide: Pentose sugar, nitrogenous base, and phosphate group.
  • DNA: Deoxyribose sugar, encodes protein synthesis (base pairs: A-T, C-G).
  • RNA: Plays a role in gene expression (base pairs: A-U, C-G).

Melting and Reannealing

• High temperature or low salt concentration causes DNA strands to separate and reattach.

Enzymes

• Proteins that accelerate chemical reactions without being consumed.

Cell Structure

• Four main components:
  • Cell Membrane: Selectively permeable, double layer of phospholipids.
  • Cytoplasm: Gel-like substance where metabolic activities occur.
  • Genetic Material: DNA housed in the nucleus or cytoplasm.
  • Ribosome: Sites for protein synthesis.

Cell Theory

• All living organisms consist of cells.
• Cells are the fundamental units of life.
• New cells arise from existing cells.

Prokaryotic Cells

• Simple structure, no nucleus or membrane-bound organelles, includes Archaea and bacteria.
• Components:
  • Flagellum (for movement), capsule (for protection), cell wall (for structure), ribosome (protein production), nucleoid (contains DNA), pili (for attachment).

Eukaryotic Cells

• More complex with nucleus and organelles, found in animals and plants.

Muscle Tissue

• Specialized for contraction:
  • Skeletal: Voluntary, striated, multinucleated cells.
  • Cardiac: Involuntary, striated, cells connected via intercalated discs.
  • Smooth: Involuntary, non-striated, found in the digestive tract.

Epithelial Tissue

• Covers body surfaces and lines cavities, classified by cell shape and layers:
  • Squamous: Thin, facilitates absorption/diffusion.
  • Cuboidal: Absorbs nutrients, found in kidney tubules.
  • Columnar: Absorbs and secretes, found in the digestive tract.
  • Pseudostratified: Appears layered, lines respiratory passages.

Connective Tissue

• Supports and protects organs, stores fat, and aids in transport and repair.

This quiz covers the major categories of biomolecules including carbohydrates, lipids, proteins, and nucleic acids. Additionally, it discusses the concepts of monomers and polymers, along with the process of dehydration synthesis. Test your understanding of these essential biological concepts.