Exam Notes

Embryonic Development

  • Fertilization:
    • Followed by rapid mitosis (cleavage) of the zygote.
  • Cleavage:
    • Zygote undergoes rapid mitosis, forming a ball of cells.
  • Gastrulation:
    • Formation of germ layers (ectoderm, mesoderm, endoderm).

Germ Layers

  • Ectoderm: Outer layer (skin, hair).
  • Mesoderm: Middle layer (muscles, blood cells).
  • Endoderm: Innermost layer (lining of gut, internal organs).

Body Symmetry

  • Bilateral: Two-sided symmetry.
  • Radial: Equal parts around a central point.
  • Asymmetry: No symmetry.

Diffusion

  • Molecules move due to kinetic energy from high to low concentration.
  • Does not require ATP.
  • Osmosis is a type of diffusion.

Cell Division

  • Major purpose: Cell division is for growth, repair, and reproduction.

Mitosis

  • Produces identical daughter cells.
  • Produces body (somatic) cells.
  • Diploid cells.

Meiosis

  • Produces sex cells (gametes).
  • Produces non-identical daughter cells.
  • Produce haploid cells.

Chromosomes

  • Gametes (sperm and egg): 23 chromosomes.
  • Somatic cells (skin, liver): 46 chromosomes.
  • Zygote: 46 chromosomes.

Reproduction

  • Animals, plants, and some fungi inherit genetic material and develop through sexual reproduction.

Cell Cycle

  • Three major events of the cell cycle:
    • Interphase, Mitosis, Cytokinesis

Cell division processes:

  • Mitosis: Division of the nucleus.
  • Cytokinesis: Division of the cytoplasm.

Events of the Cell Cycle

  • Interphase, Prophase, Metaphase, Anaphase, Telophase, Cytokinesis.
  • DNA replication happens during interphase.