18.4 Bacteria and Archaea Kingdom Eubacteria Domain Bacteria · 18.4 Bacteria and Archaea Kingdom Eubacteria Domain Bacteria . ... (See Eubacteria notes)- cocci, spirilli, ... PowerPoint

18.4 Bacteria and Archaea

Kingdom Eubacteria Domain Bacteria


Description

Bacteria are single-celled prokaryotes.


Where do they live?

Prokaryotes are widespread on Earth.

( Est. over 1 billion types of bacteria, and over 1030 individual prokaryote

cells on earth.)

Found in all land and ocean environments, even inside other organisms!


Common Examples

• E. Coli

• Tetanus bacteria

• Salmonella bacteria

• Tuberculosis bacteria

• Staphylococcus

• Streptococcus


Modes Of Nutrition

• Bacteria may be heterotrophs or autotrophs


Bacteria Reproduce How?

• by binary fission.

• exchange genes

during conjugation=

increases diversity.

conjugation bridge

TEM; magnification 6000x

• May survive by

forming

endospores =

specialized cell

with thick

protective cell wall.

• Can survive for

centuries until environment improves. Have been found in mummies!


• Bacteria Diagram

flagellum

pili

plasmid

cell wall

chromosome

plasma

membrance

This diagram shows the typical structure

of a prokaryote. Archaea and bacteria

look very similar, although they have

important molecular differences.

– plasmid = small piece of genetic material, can replicate

independently of the chromosome

– flagellum = different than in eukaryotes, but for movement

– pili = used to stick the bacteria to each other or surfaces


• Classified by: their need for oxygen, how they gram

stain, and their shapes


Main Groups by Shapes

– rod-shaped, called bacilli

Lactobacilli: rod-shaped Enterococci: spherical Spirochaeta: spiral

– spiral, called spirilla or spirochetes

– spherical, called cocci


• Main Groups by their need for oxygen.

• obligate anaerobes

are poisoned by

oxygen - Ex. Clostridium botulinum

- Ex. Clostridium tetani

– obligate aerobes

need oxygen - Ex. Mycobacterium

tuberculosis

– facultative aerobes

can live with or without

oxygen

- Ex. E. Coli


• Main Groups by Gram staining

Gram-negative bacteria have a thin layer of

peptidoglycan and stain red. Gram-positive bacteria have a thicker

peptidoglycan layer and stain purple.

– stains polymer peptidoglycan

– gram-positive stains purple, more peptidoglycan

– gram-negative stains pink, less peptidoglycan


GRAM NEGATIVE GRAM POSITIVE

– The amount of peptidoglycan within the cell wall can

differ between members of kingdom (eu)bacteria.


So, Why is Gram Staining Important?

• Different types of infectious bacterial diseases

respond differently to antibiotics when they are

gram- positive or gram-negative!


KEY CONCEPT

How Bacteria help man.


• Bacteria help ferment many foods.

– yogurt, cheese

– pickles, sauerkraut

– soy sauce, vinegar


Bacteria provide nutrients to humans and other animals.

• Live in digestive systems of animals – LIKE US!!!.

– make vitamins (Ex. E. coli in our lg. intestine make B

vitamins for us!)

– break down food (Ex. Bacteria in cow stomach digest

cellulose in grass, hay, etc.

– fill niches

Human intestinal bacteria


• Bioremediation uses bacteria to break down pollutants.

– oil spills

– biodegradable materials


How Bacteria Hurt Man!


Some bacteria cause disease.

• Bacteria cause disease by invading tissues or making

toxins.

• A toxin is a poison released by an organism.

Clostridium botulinum bacteria cause botulism food poisoning.


• Example: Flesh Eating Bacteria

– may colonize new tissues

Flesh eating Streptococcus bacteria, normally do not harm us.

Only become dangerous when come in contact with other tissues like fat or muscle.



Antibiotics are used to fight bacterial disease.

• Antibiotics may stop bacterial cell wall formation.

• Antibiotics do not work on viruses.

• Prevention is best method to fight bacterial disease.


Bacteria can evolve resistance to antibiotics.

A bacterium carries

genes for antibiotic

resistance on a plasmid.

A copy of the plasmid is

transferred through

conjugation.

Resistance is quickly

spread through many

bacteria.

• Bacteria are gaining resistance to antibiotics, due to:.

– overuse

(Handsanitizers?)

– underuse (Take your RX as directed)

– misuse (For livestock raising?)

– Read p. 565!

• Antibiotics must be

used properly.


Bacteria play important roles in ecosystems.

• Prokaryotes have many functions in ecosystems.

– photosynthesize

– recycle carbon, nitrogen,

hydrogen, sulfur

– fix nitrogen = Nitrogen

fixation

Root nodules of white clover contain

Nitrogen fixing bacteria, which convert

atmospheric nitrogen into a form the

clover can use. The bacteria get

sugars from the clovers’ photosynthesis.

This is an example of mutualistic

symbiosis.


Turn your pink sheet over, to put the Archaea on the

other side!!!!


Kingdom Archaeabacteria, Domain Archaea


Description

Archaeabacteria are single-celled prokaryotes that

live in extreme environments. They do NOT have

peptidoglycan in their cell walls.


Where do they live?

• Hot springs

• Deep sea vents

• Bottoms of Swamps

• Mouths of volcanoes

• Extra Salty lakes and seas


Common Examples

• Methanogens = methane gas lovers

• Thermophiles = heat lovers

• Halophiles = salt lovers


Modes of nutrition

• Heterotrophs and Chemoautotrophs

• Chemoautotrophs use chemicals in their environment to

create their own food

(Unlike photosynthesizers, that rely on energy from the

sun.)


Reproduce how?

• Same as Eubacteria


Diagrams (omit)

flagellum

pili

plasmid

cell wall

chromosome

plasma

membrance

This diagram shows the typical structure

of a prokaryote. Archaea and bacteria

look very similar, although they have

important molecular differences.


Classified by:

• Shapes (See Eubacteria notes)- cocci, spirilli, bacilli

• Where they live


Main Groups – see common examples


Special roles in ecosystems – fill niches in extreme

environments • Fill niches in extreme environments

• Many of them are chemosynthesizers

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18.4 Bacteria and Archaea Kingdom Eubacteria Domain Bacteria · 18.4 Bacteria and Archaea Kingdom Eubacteria Domain Bacteria . ... (See Eubacteria notes)- cocci, spirilli, ... PowerPoint