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

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)

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.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 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 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

MutationsQuick 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