Cell

2022-04-06: reference:

Cell #

• A eukaryotic cell consists of its:
  • Cell membrane?
  • Nucleus
    • Nucleolus
      • Aggregates RNA for ribosomes themselves, with associated proteins, to assemble them. It is transported through the pores. It’s a mess of >200 proteins.
  • Cytoplasm
    • Cytosol (cytoplasmic matrix), where all organelles are in.
    • Cytoskeleton
      • Consists of Microtubules, centrosomes, microfilaments, and intermediate filaments.
    • Synthesizes proteins for ribosome biogenesis, where they are imported through nuclear pores.
    • ~70-80% water. Proteins give it a gelid consistency.
  • Nucleus
    • Contain’s the cell’s genome, besides the mitochondrial DNA. DNA/RNA synthesis
  • Ribosome
  • Vesicles
  • Golgi apparatus: After they leave the ER, modification/sorting/packaging of proteins/lipids for secretion or delivery to other organelles.
  • Rough Endoplasmic Reticulum
  • Smooth Endoplasmic Reticulum
  • Mitochondria
  • Vacuole
  • Lysosome
  • Peroxisome - found in all eukaryotic cells actually.
  • Endosome

Plant Cells #

!Botany

Prokaryotes #

Defined as lacking a nucleus and other organelles.

• ,

  • Contains unpaired (haploid), cirular chromosomes. Nucleoid-associated proteins assist in organizing and packaging the chromosome.
  • Has extrachromosomal DNA found in plasmiads, of which there are often hundreds per cell. They do exist in archaea and eukaryotes but are mostly a bacterial thing.
  • Flagella are used for movement in aqueous environments.

• It’s possible Eukaryotes evolved from symbiosis between gram-positive bacteria and archaea, forming the double membrane. A similar thing is seen in mitochondria and chloroplasts:

  • Which is more intuitive? I dunno, probably organelle-first. The eukaryote-first hypothesis proposes that prokaryotes actually evolved from eukaryotes by losing genes and complexity.

Archaea #

• Archaeal membrane phospholipids are formed with ether linkages, as opposed to ester.
• Methanogens use hydrogen for electrons for reducing CO2 to food, producing CH4. This is what the bacteria in rumens do, as well as our colon.
• Some archaea grow at 121°C or at pH 1. This has interesting commercial implications.