Structure of prokayrotic cells and virus cells

• Key/main Differences between prokaryotic and eukaryotic cells

  The cells are much smaller

  no membrane bound organelles (except for ribosomes)

  smaller ribosomes

  no nucleus

  murein cell wall
• Prokaryotic exclusive organelles/features

  Plasmids

  a capsule around the cell

  Flagella
• membrane bound organelles NOT found in prokaryotic cells

  Mitochondria

  chloroplasts

  endoplasmic reticulum

  golgi

  nucleus
• Membrane bound organelles found in prokaryotic cells

  Ribosomes
• Structure of ribosomes

  small in size

  made up of two sub-units of protein and rRNA

  80s - larger ribosomes found eukaryotic cells (25nm)

  70s - smaller ribosomes found in prokaryotic cells, mitochondria and chloroplasts
• why does the mitochondria and chloroplast have their own 70s ribosomes

  So that these organelles can continuously create their own proteins (typically enzymes) for photosynthesis and respiration
• Structure of ‘nucleus’

  No nucleus

  singluar circular DNA molecule free in cytoplasm

  not protein bound
• Structure of cell wall

  contains murein ; a glycoprotien/ polysaccharide and peptide mix
• Structure/function of plasmid

  *ONLY PRESENT IN SOME PROKARYOTIC CELLS*

  small loops of DNA

  carries a few genes ( where antibiotic resistance genes are found in bacteria cell is antibiotic resistant )
• Structure/Function of capsule

  *ONLY PRESENT IN SOME PROKARYOTIC CELLS*

  Is a slimy layer made of protein which allows multiple bacteria cells to stick together

  Layer prevents the bacteria from desiccating (drying out)

  protects the bacteria against host’s immune system, antibiotics and viruses ( by covering bacterias antigens )
• Structure/Function of flagella

  *ONLY PRESENT IN SOME PROKARYOTIC CELLS*

  some bacteria can have multiple flagellum

  rotates at base to propel the bacteria to enable its movement ( locomotion )
• Structure/function of mesosome/membrane infold

  folded structure inside bacteria cell providing an increased surface area

  increased surface area for respiration to take place
• Viruses

  Regarded as a complex molecule

  Acellular (isn't made up of cells)

  non-living particles

  1000x smaller than bacteria

  consists of a genetic material (RNA) that are protected by a protein coat called the capsid

  may be enclosed in a lipid envelope

  the capsid/lipid envelope will have attachment proteins to help recognise a host cell