Presentation on theme: "An introduction to bacteria They Are Everywhere. Prokaryotes Prokaryote: Single-celled organism that lacks a true nucleus (also called bacteria) Prokaryote:"— Presentation transcript:
Prokaryotes Prokaryote: Single-celled organism that lacks a true nucleus (also called bacteria) Prokaryote: Single-celled organism that lacks a true nucleus (also called bacteria) DNA is not surrounded by a nuclear membrane, have no membrane bound organelles. Cover almost every Cover almost every cm 2 of earth!
Size Matters Prokaryotes = 1-5 micrometers Prokaryotes = 1-5 micrometers Eukaryotes = 10-100 micrometers Eukaryotes = 10-100 micrometers Vs. Prokaryotic cells are much smaller than eukaryotic cells.
One to Two *Until recently all prokaryotes were one kingdom, Monera *Until recently all prokaryotes were one kingdom, Monera Monera is now split into 2 kingdoms: Monera is now split into 2 kingdoms: Eubacteria, Archaebacteria Eubacteria, Archaebacteria Now three domains 1)Eubacteria/Bacteria 2)Archaea 3)Eukaryota/Eukarya
Archaebacteria ! A hot springs in Yellowstone National park!
Archaeabacteria Lack peptidoglycan walls and have different membrane lipids than Eubacteria Lack peptidoglycan walls and have different membrane lipids than Eubacteria DNA sequences are closer to Eukaryotes than Bacteria DNA sequences are closer to Eukaryotes than Bacteria
Extremophiles – ‘phileo’ in Greek means love Extremophiles: Extremophiles: –Live in extreme environments!
Methanogens – produce methane gas Live in the gut of mammals, sewage disposal plants and swamps
Eubacteria Largest of prokaryote groups Largest of prokaryote groups *Have cell walls that contain peptidoglycan (carbohydrate) *Have cell walls that contain peptidoglycan (carbohydrate) Find everywhere on earth. Find everywhere on earth.
Shapes Three Shapes Three Shapes 1)Bacilli (rod-shaped) 2) Cocci (spherical) 3) Spirilla (spiral or corkscrew)
Cell Walls Two Types of Eubacteria: Two Types of Eubacteria: –Gram-Positive Thick peptidoglycan walls Turn dark purple when stained –Gram-Negative Much thinner walls inside an outer lipid layer Appear pink or light red
Flagella Ribosome Pili Cell membrane DNA Cytoplasm Plasmid Cell wall Capsule
Pili - Help with conjugation – transferring of genetic material p.558, Stick to host’s cells Flagella: Movement Ribosomes- Making proteins DNA - Carries the genetic material Cytoplasm - Contains DNA, Proteins and plasmid Plasmid – piece of DNA, plays role during conjugation Capsule – Protects against drying out, chemicals and host’s white blood cells. Cell wall - Protects, gives cell shape Eubacteria–has peptidoglycan Cell membrane – Regulates the movement of materials in and out of the cell
Heterotrophs Parasitic – Cause diseases (pathogens) Parasitic – Cause diseases (pathogens) Saprophytic – Feed on dead tissues - Decomposers Saprophytic – Feed on dead tissues - Decomposers
Autotrophs Photoautotrophs: Photoautotrophs: –Use light energy to convert CO 2 and H 2 O to food (like plants) –Ex: cyanobacteria Chemoautotrophs: Chemoautotrophs: –Use chemical energy to convert CO 2 and H 2 O to food
Releasing Energy Obligate Aerobes: Obligate Aerobes: –Require constant supply of oxygen Obligate Anaerobes: Obligate Anaerobes: –Do not require oxygen... It kills them Facultative Anaerobes: Facultative Anaerobes: –Do not require oxygen, but can live with it –Ex: E. coli
*Growth and Reproduction Some bacteria can divide every 20 minutes Some bacteria can divide every 20 minutes –If there was unlimited resources 1 bacteria could grow into a mass 4000 times the mass of earth in just 48 hours!!!
Nitrogen Fixation Converting nitrogen gas into a form plants can use (nitrates – NO 3 ) Converting nitrogen gas into a form plants can use (nitrates – NO 3 ) –Allows nitrogen to cycle through biosphere For example Rhizobium living in the roots of legumes such as soybean plants.
Other Uses Oil digestion/ Oil digestion/ Clean up of pollutants (Bioremediation)
Are living: 1.Made up of cells 2.Have DNA 3.Grow and develop 4.Use energy 5.Homeostasis 6.Reproduction 7.Respond to stimuli 8.Evolve/Show adaptations – resistant bacteria 9.Show some type of organization – Flagella, pili, ribosomes, cell wall