monera

• Monera

  Bacteria are the most numerous organisms on earth and are found everywhere
• Bacteria habitats


  • Acid, hot volcanic pools, inside nuclear reactors
• You have more bacteria living inside and on your skin then there are cells in your body itself
• Organisms in the kingdom Monera

  Also called Prokaryotes
• Bacteria


  • Unicellular
  • Prokaryotic - do not have a nucleus or membrane enclosed organelles
  • Reproduce asexually
  • Microscopic - very small

  
• You can fit a million bacteria on the tip of a pin

  
• Structure of a Bacterial Cell

  • Cell wall
  • Slime Capsule
  • Cytoplasm
  • Flagella
  • Chromosome
  • Plasmid

  
• Cell wall


  Protect bacteria from damage or osmotic rupture
• Slime Capsule


  Protects bacteria from drying out
• Cytoplasm


  Contains ribosomes and storage granules
• Flagella


  Enable bacteria to be motile

  
• Chromosome


  Loop of DNA
• Plasmid


  Circular piece of DNA containing a few genes for drug resistance
• Bacterial Shapes


  • Round (cocci)
  • Rods (bacilli)
  • Spirals (spirillum)

  
• Bacterial Reproduction


  1. Binary Fission

  2. Genetic material and plasmids replicate and move to either side of the cell

  3. Cell pinches its membrane

  4. Cell wall grows across the middle

  5. Produces 2 identical cells

  
• Bacterial cells do not have a nucleus
• Under ideal conditions a bacterial cell can replicate every 20 minutes
• Huge numbers of bacteria can be produced from just one bacterium in 24 hours
• Bacteria reproduce asexually so the offspring are genetically identical - clones
• Mistakes sometimes occur when the genetic material is being copied - mutations
• The numbers of bacteria are so large that even though mutations occur very occasionally, there can actually be a large number of them in a colony
• Most mutations are fatal or at least damaging to the bacterium
• As they replicate so quickly, if a mutation is advantageous, the new strain quickly becomes dominant
• This is why bacteria evolve rapidly
• Endospore


  Structure formed by a bacterium when exposed to adverse conditions

  
• Endospores can remain viable for centuries
• Endospore activation


  1. Genetic material replicates

  2. Normal bacterium forms

  
• People dealing with corpses and skeletons have to be careful to wear protective clothing to prevent infection from endospores
• Bacterial Nutrition


  • Autotrophic
  • Heterotrophic
• Autotrophic Bacteria


  Can make their own food
• Types of Autotrophic Bacteria

  • Photosynthetic
  • Chemosynthetic
• Photosynthetic Bacteria


  Use light energy to make their food (e.g. purple sulfur bacteria)
• Chemosynthetic Bacteria


  Use energy from chemical reactions to make their food (e.g. nitrifying bacteria)
• Heterotrophic Bacteria


  Cannot make their own food
• Types of Heterotrophic Bacteria

  • Saprophytic
  • Parasitic
• Saprophytic Bacteria


  Live off dead organic matter (e.g. bacteria of decay)
• Parasitic Bacteria


  Feed off a live host, causing them harm
• Factors Affecting Bacterial Growth

  • Temperature
  • pH
  • Oxygen Concentration
  • External Solute Concentration
  • Availability of water and nutrients
• Temperature


  Affects the rate of enzyme activity, bacteria function best at around 35-40°C
• pH


  Majority of bacteria function best around pH 7, unsuitable pH can denature enzymes