PROKARYOTES, BACTERIA, & VIRUSES By carter reid

Eukaryotes v. Prokaryotes

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

SHAPE of Bacteria  Cocci – spherical, round shape  Bacilli – rod-shaped  Spirilli – spiral - shaped  Strepto – long chains  Staphylo – clumps  Diplo - pairs

Let’s Practice… DRAW THE FOLLOWING BACTERIA: 1.Staphylococcus 2.Streptococcus Now, write the types from the pictures below…

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 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