biology

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  • Created by: sarah
  • Created on: 15-09-12 14:08

Prokaryotic Cell

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Prokaryotic Cell functions

  • Plasma Membrane -controls the movement of substances into and out of cells.
  • Cytoplasm -Site of chemical reactions within the cell.
  • Genetic Material -Composed of a circle of double stranded DNA. 
  • 70s Ribosomes -Used for protein synthesis
  • Cell Wall -Made of peptidoglycan. Provides structural support. Prevents osmotic damage when water enters the cell.
  • Pili -Small hair like appendages around the outside of the cell. For adhesion and to transfer genetic material between bacteria. 
  • Flagellum -Longer appendage which is used for locomotion and often also a sensory organelle.
  • Food stores -Typically lipid globules or glycogen granules.
  • Photosynthetic membranes -Surfaces for light absorbing pigments.
  • Plasmids -Short pieces of circular DNA which replicate independently of the genome.
  • Capsule -A gummy layer of mucilage,may unite bacteria into colonies or confer protection.
  • Mesosomes -infoldings of the plasma membrane in which enzymes associated with with respiration are located (where energy happens). A protein gradient generated across these membranes is used to drive the synthesis of ATP. 
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Difference between Prokaryotic and Eukaryotic Cell

  • Size- Prokaryotic smaller (1-10 µm), Eukaryotic larger (10-100  µm)
  • Cell Wall- Prokaryotic consists of murein, Eukaryotic consists of cellulose or chitin
  • Membrane Bound Organelles- Prokaryotic has none, Eukaryotic has them
  • DNA- Prokaryotic circular but there are no true chromosomes present, Eukaryotic DNA is in the nucleus with proteins which form chromosomes 
  • Ribosomes- Prokayotic they are smaller 70s, Eukaryotic larger 80s
  • Nucleus- Prokaryotic none, Eukaryotic the nucleus is surronded by a nuclear envelope
  • Nucleolus- Prokaryotic none, Eukaryotic nucleolous present
  • Microtubules- Prokaryotic Flagellum lacks microtubules, Eukaryotic9+2 arrangement of microtubules. 
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