Prokaryote Characteristics Single cell No true nucleus Few organelles Archaebacteria – extreme environments Eubacteria – “normal” bacteria
Eukaryotes v. Prokaryotes Eukaryotes Larger (up to 100 times!) More complex Nucleus Have chromosomes Membrane bound organelles Ex: Animals, plants, protists Prokaryotes Smaller Not as complex No nucleus Have single strand of DNA and plasmid No membrane bound organelles Ex: Bacteria
CHARACTERISTICS of Bacteria Prokaryotes – meaning “before a nucleus” Divided into 2 domains Bacteria Archaea
Archaebacteria Dominate in extreme environments 3 types Thermoacidophiles Hot, acidic areas (ex: sulfur hot springs, thermal vents on ocean floor) Halophiles Very salty areas, usually aerobic (ex: Great Salt Lake, Dead Sea) Methanogens No oxygen (anaerobic) areas, take in oxygen and give off methane (ex: sewege treatment, swamps, bogs)
EUBACTERIA Most studied organism Found everywhere, except extreme environments Very strong cell walls (has peptidoglycan) Some have a second cell wall
PROKARYOTE STRUCTURE Genetic material (DNA) Flagella Pili Ribosomes Capsule
FUNCTION of the Structure DNA – found in nucleoid (Remember: prokaryotes DO NOT have a nucleus) Capsule – polysaccharide layer (aka sugar), prevents dry-out, helps attach cell to surfaces, prevents WBC’s from “eating” them Pili – made of protein, hair-like, also helps attachment, can act as a bridge between cells Flagella – helps with locomotion (aka movement) Ribosomes – make proteins for the chromosomes
HOW DO WE IDENTIFY BACTERIA?? Shape Cell Walls Movement
Let’s Practice… DRAW THE FOLLOWING BACTERIA: 1.Staphylococcus 2.Streptococcus Now, write the types from the pictures below… 1.2.3.
CELL WALLS Have peptiodglycan (made of dissacharides & peptide fragments) Why is it important for bacteria to have strong cell walls?
MOVEMENT Some are stationary Some use flagella to move
Bacteria REPRODUCTION Sexual Reproduction – called Conjugation Cells attach and exchange info Asexual Reproduction – called Binary Fission Chromosome replicates, then separates Can happen every 20 min. Becomes 1 BIL. IN 10 HRS!
METABOLISM of Bacteria Photoautotrophs Do photosynthesis need light to live Called cyanobacteria Release Oxygen into the environment Chemoautotrophs Do not require light Break down & release inorganic compounds (Nitrogen or Sulfur) and keeps them cycling Aerobes Require oxygen to grow Anaerobes Do not require oxygen, use fermentation instead
SURVIVAL Endospores Dormant cell Resistant to harsh conditions Forms around chromosome and small part of cytoplasm Ex: anthrax, botulism, tetanus Mutations Quick reproduction, so genetic mutations help survival Leads to “antibiotic - resistant bacteria”
ECOLOGY of Bacteria Bacteria are decomposers and return vital nutrients to the soil/environment NORMAL FLORA – harmless bacteria in & out of your body E.Coli in your intestines makes Vitamin K (for blood-clotting) DIFFERENT from the food poisoning kind
FOOD & MEDICINE Cheese, yogurt, pickles – made w/the help of bacteria Used to make CHOCOLATE (bacteria breaks down the cocoa bean covering) MEDICINE – some anti-biotics (ex: tetracycline) originally made by bacteria
DISEASE –CAUSING Bacteria Only a small % of bacteria ACTUALLY cause disease They harm in two ways… Bacteria multiply quickly @ the infection site Bacteria secrete a toxin that can cause harm (ex: Botulism – paralyzes nervous system cells)
DISEASE –CAUSING Bacteria PATHOGENS – disease- causing bacteria ANTIBIOTICS – block the growth & reproduction of bacteria (they break down the cell wall)
How to Control “BAD” Bacteria STERILIZATION – heat or chemically treat bacteria to kill it Disinfect – chemical solution kills bacteria Refrigerate – bacteria grows slower in the cold Heat/Boil – high temps kill bacteria