Biological Principles Review Notes

Organic Molecules

  • Carbon-containing compounds found in living things.
    • Carbohydrates: Energy source, made of carbon, hydrogen, and oxygen (2:1 ratio of hydrogen to oxygen).
    • Proteins: Nitrogen-containing chains of amino acids; form enzymes, hormones, antibodies, and structural components.
    • Lipids: Water-insoluble fats and oils composed of glycerol and fatty acids; provide insulation and store energy.
    • Nucleic Acids: Direct protein instruction and genetic information (DNA and RNA).

Cell Organelles

  • Chloroplast: Captures solar energy for photosynthesis.
  • Golgi Body: Packages and distributes products.
  • Lysosomes: Digests excess products and food particles.
  • Mitochondria: Transforms energy through respiration.
  • Nucleus: Contains DNA and controls cellular activities.
  • Ribosome: Produces proteins.
  • Vacuole: Stores substances.
  • Cell (plasma) membrane: Phospholipid bilayer controlling transport and maintaining homeostasis.
  • Cell wall: Rigid layer for protection (plant cells and some bacteria).
  • Cytoplasm: Fluid-like substance containing organelles.
  • Endoplasmic Reticulum: Site of chemical reactions; Rough (contains ribosomes) & Smooth (lipid production).
  • Cytoskeleton: Provides internal structure; microfilaments (fibers) & microtubules (cylinders).

Cell Types

  • Unicellular: Single, independent cell.
  • Multicellular: Specialized groups of cells organized into tissues, organs, and organ systems.
  • Prokaryote: Nuclear material without a nuclear membrane; no membrane-bound organelles (bacteria).
  • Eukaryote: Nucleus enclosed by a nuclear membrane and membrane-bound organelles (plants, animals, fungi, protists).

Cell Theory

  • The cell is the basic unit of life.
  • All organisms are composed of cells.
  • All cells come from pre-existing cells.

Cell Specialization

  • Cells > Tissues > Organs > Organ Systems > Organism.
  • Cells perform specific functions; design and shape dictated by function and conditions.
  • Multicellular organisms have greater cellular specialization (e.g., red blood cells, nerve cells).