Lesson 5.1: The Bacteria and Archaea PART 2

Cell wall

gives shape to the bacterium

• provides structural support that keeps bacterium from bursting or collapsing

because of changes in osmotic pressure.

• made up of peptidoglycan (PG) which in turn is made up of (alternating glycans,

N-acetyl glucosamine (G) and N-acetyl muramic acid(M) bound together in long strands

protoplast

Gram positive + lysozyme =

spheroplast

Gram negative + lysozyme =

protoplast

(cell wall completely removed)

spheroplast

only a part of cell wall is removed

1.Mycoplasma

2.Phytoplasma

3.Spiroplasma

There are bacteria that naturally lack cell wall or

Cell Wall-Deficient Bacteria (CWDB)

1.Mycoplasma

eg. Mycoplasma pneumoniae

which cause primary atypical pneumonia in humans

2.Phytoplasma

• Known as mycoplasma-like organisms)

cause coconut lethal yellowing, little leaf disease

of ampalaya and patola, cassava phytoplasma disease

3.Spiroplasma -

cause corn stunt and citrus decline

The Cell Membrane

• thin (5-10 nm) flexible sheet molded completely around the

cytoplasm

• composed of lipid bilayer with embedded protein

• regulate transport of substances into and out of the cell

• site for energy reactions, nutrient processing and

synthesis

The Cytoplasm

• found encased by the cell membrane

• gelatinous solution made up of water (70 – 80%), and a

complex mixture of nutrients including sugars, amino acids

and salts

• site for many biochemical and synthetic activities of the cell

1.chromatin body

represents the

genetic material of bacteria which come

as single circular strand of DNA; found in

cell area called nucleoid

2.plasmids

essential pieces of DNA

duplicated and passed on to offspring;

confer protective traits such as

resisting drugs and producing toxins

and enzymes

3.ribosomes

site of protein synthesis

Cell inclusions

represent stored food like glycogen;

• in some aquatic bacteria, they come as gas vesicles for

buoyancy and flotation.

• Some contain crystals of inorganic compounds, termed

metachromatic granules

Bacterial Endospores

Dormant bodies produced by Bacillus, Clostridium and Sporosarcina

for withstanding adverse conditions and facilitating survival

• The depletion of nutrients, like adequate carbon or nitrogen source,

stimulates vegetative cell to begin endospore formation(6-8 hrs)

Bacillus anthracis

Clostridium tetani

C. perfringens

C. botulin

What are the several bacterial pathogens are endospore formers:

Bacillus anthracis

anthrax

Clostridium tetani

tetanus

C. perfringens

cause gas gangrene- toxin cause

death of affected tissues which release gas.

C. botulin

botulism (food poisoning). The

disease begins with weakness, blurred vision,

feeling tired, and trouble speaking.

The Archaea

prokaryotic single-celled organisms belonging to

Domain Archaea

• also known as extremophiles

• Can sustain in extremely harsh environment such as

oceans, hot springs, marshlands, and gut of humans

• They reproduce asexually by binary fission,

fragmentation, or budding

the methanogens

•strict anaerobes (live

without O2); convert CO2

and H2 into methane gas

(CH4)

•important in biodegradation

of organic matter and most if

not all natural gas on Earth

has accumulated from their

metabolism

Methanobacterium

are common in some hot, low-oxygen environments, such

as anaerobic digesters, their wastewater, and hot springs

• reproduce using binary fission (by constriction), and are motile

The halophiles

( e.g.Halobacterium)

• "salt-loving" or "ocean bacterium

• require oxygen and very large

amounts of salt (NaCl) for

metabolism and reproduction

• may be either rods or cocci, and

either red or purple

• Halophiles have aerobic metabolism

• Halobacterium grows best in

a 42 °C environment

3.The hyperthermophiles

high temperature loving

• flourish at temperatures between 80oC and 113oand

cannot grow at 50oC

• e.g. Thermoplasma and Thermophilus

The Acidophiles

acidophilic organisms are those that thrive under highly

acidic conditions (usually at pH 2.0 or below).

• These organisms can be found members of

Archaea, Bacteria and Eukarya

Extremozymes

produced by extremophiles are useful in

industrial production procedures and research

applications because of their ability to remain active

under the severe conditions

Biofuel

methane gas from Methanogens

Halophiles

may prove to be valuable bioremediation

agents for the treatment of saline effluents and

hypersaline waters contaminated with toxic compounds

that are resistant to degradation.

Biomining

eg. metals such as gold, silver, copper, zinc,

nickel, and uranium. The organisms used in this process

are acidophiles.

lysozyme

an enzyme that degrades the peptidoglycan layer