Biology Endosymbiotic Theory Quiz

Endosymbiotic Theory

• Certain eukaryotic organelles originated from independent prokaryotic cells.
• Both prokaryotes and eukaryotes have membrane-bound organelles, but prokaryotes lack a nucleus.

Prokaryotes

• Include bacteria and archaea.
• Have a nucleoid region containing their DNA.
• Possess various membrane-bound organelles:
  • Plasma membrane: composed of phospholipids and proteins.
  • Cell wall: provides structural support and is made of peptidoglycan.
  • Glycocalyx: an outer coating that can be a slime layer.
  • Flagella: for locomotion.
    • Monotrichous: one flagella at one pole.
    • Lophotrichous: multiple flagella at one pole.
    • Peritrichous: flagella distributed all around the cell.
    • Amphitrichous: one flagella at each pole.
  • Ribosomes: composed of RNA and protein, responsible for protein synthesis.

Eukaryotes

• More complex organisms, including plants, animals, fungi, and protists.
• Possess a nucleus and other membrane-bound organelles.

Eukaryotic Organelles

• Nucleus:
  • Contains most of the cell's genes.
  • Houses chromatin, which forms chromosomes.
  • Contains a nucleolus, the site of ribosomal RNA synthesis.
  • Encased by a nuclear envelope, a double phospholipid bilayer.
  • Possesses nuclear pores for regulating molecule passage.
  • Has a nuclear lamina that maintains the nucleus's shape.
• Endoplasmic Reticulum:
  • Smooth reticulum: synthesizes lipids, metabolizes carbohydrates, detoxifies, and stores calcium.
  • Rough reticulum: secretes glycoproteins and distributes vesicles.
• Golgi apparatus: modifies, manufactures, and packages transport vesicles.
• Lysosomes:
  • Digest macromolecules.
  • Involved in:
    • Phagocytosis: engulfing cells to form vacuoles.
    • Phagolysosome: fusion of lysosomes and vacuoles.
    • Autophagy: absorbing useless cellular components.
• Vacuoles:
  • Food vacuoles.
  • Contractile vacuoles: pump water.
  • Central vacuoles: found in plant cells.

Other Eukaryotic Organelles

• Mitochondria:
  • The site of cellular respiration, generating ATP (energy source).
  • Has a smooth outer membrane and an inner membrane.
• Chloroplast:
  • Found in plants and algae, contains chlorophyll.
  • Includes thylakoids (sacs) and stroma (internal fluid).
• Peroxisome:
  • Converts hydrogen peroxide to water.
• Cytoskeleton:
  • Supports cells and maintains their shape.
  • Composed of three types of fibers:
    • Microtubules: thickest, control the beating of cilia and flagella.
    • Microfilaments: thinnest, play a role in cell structure, organization, and movement.

Test your knowledge on the Endosymbiotic Theory and the differences between prokaryotes and eukaryotes. This quiz covers the origins of eukaryotic organelles, the structure of prokaryotic cells, and more. Dive into the fascinating world of cellular biology!