CELL THEORY

  • Key features of cell theory:
    • All living organisms are composed of cells.
    • Cells are the basic unit of structure and function in organisms.
    • All cells arise from pre-existing cells.

PROKARYOTES VS EUKARYOTES

Prokaryotes:
  • Circular strand DNA
  • Unicellular
  • Size: 1-10 micrometers
  • No nucleus/nuclear membrane
  • Includes bacteria and blue-green algae
  • Reproduction method: binary fission
  • No membrane-bound organelles; only ribosomes
Eukaryotes:
  • Multicellular (animals, plants, fungi)
  • Contains a nucleus
  • Has organelles with specialized functions
  • Complex internal structure

PLANT VS ANIMAL CELLS

  • Identify key features:
    • Plant cells have cell walls and chloroplasts, while animal cells do not.
    • Animal cells have lysosomes and centrioles, while plant cells do not.

CELL ORGANELLES

  • Roles of organelles:
    • Cell Membrane: Regulates movement of substances in and out of the cell.
    • Cell Wall: Provides support and protection (in plants).
    • Nucleus: Stores genetic material and coordinates cell activities.
    • Endoplasmic Reticulum: Synthesizes proteins and lipids.
    • Golgi Body: Modifies, sorts, and packages proteins.
    • Chloroplasts: Site of photosynthesis (in plants).
    • Ribosomes: Protein synthesis.
    • Mitochondria: Powerhouse of the cell, ATP production.

MOLECULAR MOVEMENT

  • Passive Transport: No energy required.
    • Includes diffusion, facilitated diffusion, osmosis.
  • Active Transport: Requires energy.
    • Includes active transport, endocytosis, exocytosis.
  • Concentration gradient: Movement of substances from high to low concentration.

CELL STATE & OSMOSIS

  • Osmosis impact on cell state:
    • Hypotonic: Water enters, turgor pressure increases.
    • Isotonic: Balanced water movement.
    • Hypertonic: Water leaves, cell shrinks.
  • Direction of water flow influenced by solute concentration.

SCIENCE INQUIRY SKILLS

  • Identify Independent Variable (IV) and Dependent Variable (DV).
  • Importance of increasing sample size:
    • Improves data reliability.
  • Resolution: Measure of clarity; higher resolution glassware provides more accurate measurements.

CELL DIVISION

  • Binary Fission: Process of prokaryotic cell division.
  • Mitosis: Stages include:
    • Prophase, Metaphase, Anaphase, Telophase; involves movement of sister chromatids.
  • Cell cycle phases:
    • G1 Phase: Growth and preparation for DNA replication.
    • S Phase: DNA synthesis/replication.
    • G2 Phase: Final preparations for mitosis.
  • G0 Phase: Non-dividing state for differentiated cells; stem cells can re-enter the cycle.
  • Semi-conservative replication: Each daughter DNA strand contains one original and one new strand.