Biology

• Bacterium


  Single-celled organism
• Bacteria


  Plural of bacterium
• Archaeon


  Single-celled organism
• Archaea


  Plural of archaeon
• Mitochondrion


  Organelle found in eukaryotic cells
• Mitochondria


  Plural of mitochondrion
• Scale bars should be used to estimate sizes in images
• Macrophage


  Type of immune cell
• Binomial nomenclature


  Genus name written with capital letter, species name written in italics
• After first mention, genus name can be abbreviated
• Cells


  • Insides are watery ("aqueous")
  • Concentrated solutions of proteins and salts, with smaller quantities of other molecules
• Organelles


  Membrane-bound structures within eukaryotic cells (e.g. nucleus, endoplasmic reticulum, Golgi, lysosome, peroxisome, mitochondria, chloroplast, vesicle)
• Organelle can also refer to subcellular structures that are not membrane-bound, such as ribosomes
• Cytoplasm


  Everything between the nucleus and the cell membrane in a eukaryotic cell

  
• Cytosol


  Smaller region within the cytoplasm
• Nucleus


  Contains DNA wrapped around histones
• Nuclear envelope


  Outer and inner membranes
• Rough ER


  Studded with ribosomes, proteins made there may move through vesicles to the Golgi and then to lysosomes or get secreted
• Endomembrane system


  Nuclear envelope, smooth ER and rough ER are one giant membrane enclosing a single space, Golgi, lysosomes and cell membrane interact with this through vesicles

  
• Differences between prokaryotes and eukaryotes

  • Prokaryotes have single circular chromosome, no histones, reproduce by binary fission, have prokaryotic ribosomes
  • Eukaryotes have multiple linear chromosomes, DNA associated with histones, reproduce by mitosis or meiosis, have eukaryotic ribosomes
• Endosymbiotic origin of mitochondria

  1. Engulfing of bacterium, which after a long time becomes a mitochondrion

  2. Ancestor of eukaryotic cells (host cell) gains energy, protection, food, homeostasis

  3. Small cell (bacterium) gains benefits from being engulfed
• Earth cool enough for crust to solidify

  Origin of Earth