PROKARYOTES, BACTERIA, &

VIRUSESBy carter reid

Eukaryotes v. Prokaryotes

Prokaryote Characteristics

Single cellNo true nucleusFew organellesArchaebacteria –

extreme environmentsEubacteria –

“normal” bacteria

Eukaryotes v. ProkaryotesEukaryotes

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 domainsBacteriaArchaea

Archaebacteria Dominate in extreme environments 3 types

ThermoacidophilesHot, acidic areas (ex: sulfur hot

springs, thermal vents on ocean floor)Halophiles

Very salty areas, usually aerobic (ex: Great Salt Lake, Dead Sea)

MethanogensNo 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)

FlagellaPiliRibosomesCapsule

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??

ShapeCell WallsMovement

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.Staphylococcus2.Streptococcus

Now, write the types from the pictures below…

1.2. 3.

CELL WALLSHave peptiodglycan (made of dissacharides & peptide fragments)

Why is it important for bacteria to have strong cell walls?

MOVEMENT

Some are stationarySome use flagella to move

Bacteria REPRODUCTION Sexual Reproduction – called

ConjugationCells attach and exchange info

Asexual Reproduction – called Binary FissionChromosome replicates, then

separates Can happen every 20 min. Becomes 1 BIL. IN 10 HRS!

METABOLISM of Bacteria Photoautotrophs

Do photosynthesis need light to liveCalled cyanobacteria Release Oxygen into the environment

ChemoautotrophsDo not require lightBreak 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 cellResistant to harsh conditionsForms around chromosome and

small part of cytoplasmEx: anthrax, botulism, tetanus

MutationsQuick reproduction, so genetic

mutations help survivalLeads 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