PART I Chapter 18

Archaebacteria & Eubacteria

Phylogeny

Characteristics• First living evidence on earth • Unicellular• Prokaryotes (No membrane-bound organelles)• Cell wall with internal plasma membrane• Found everywhere

Bacteria

Bacteria Structures• Cell wall – provides support and protection to

the cell

• Plasma membrane – flexible, selectively permeable boundary that controls what enters and leaves the cell

• Cytoplasm – semi-fluid material inside the cell’s plasma membrane

• Ribosome – organelle that helps to manufacture proteins

• DNA - stores and communicates genetic information for the cell

Bacteria Structures

• Pilus/pili - hairlike protrusion– to stick to surfaces– a bridge for sexual reproduction

• Flagellum - long, whiplike protrusion, for moving

• Capsule - sticky layers around cell wall

• Toxin - a powerful poison

• Endospore – found in some bacteria - resists harsh environments

Flagella

Capsules

Endospores

Endospores

Classification:Three Basic Shapes

Cocci -Spheres

Bacilli -Rods

Spirilli -Spiral

Classification:

• Gram stain – Cell wall type

• Thick – Purple Stain = “Gram Positive”

• Thin - Pink Stain = “Gram Negative”

Growth Patterns

Diplo- pairsStaphylo- clusters Strepto- chains

Streptococci

Pneumonia

PART IIChapter 18

Archaebacteria & Eubacteria

Archaebacteria – ancient bacteria

Methanogens

Live in:Oxygen-free environment

Produce methane gas

Halophiles

Live in:Salt water

Acidophiles:

Live in:Hot, acidic

water

Eubacteria - “True” bacteria

Heterotrophs

Photosynthetic

Autotrophs

Chemosynthetic

Autotrophs

Saprophytes (decomposers)

Need sunlight to make food

Need sulfur & nitrogen to make food

Parasites (cause disease)

Example: Cyanobacteria

Nitrogen fixation

(FIX the nitrogen)

Live in more habitable environments

Cyanobacteria - “blue-green bacteria”Algae + Bacteria

Sulfur Bacteria

Beneficial Bacteria• Nitrogen fixation

– Converts nitrogen into ammonia

– a form that plants can use

• Nodules – A symbiotic relationship

between bacteria and plants

(Beneficial Bacteria)

Saprophytes (decomposers) – Breaks down dead organisms and

decaying matter– Returns nutrients to soil

(Beneficial Bacteria)

Make food:– Cheese– Pickles– Yogurt– Vinegar– Sauerkraut

Cellular Respiration

Obligate Aerobes

Obligate Anaerobes

Need Oxygen Die from Oxygen

Pathogenic Bacteria – disease-causing bacteria

• Pathogen – an organism that causes disease

• Produce toxins

• Damage host’s tissues

• Enter through openings in body (via air, food, water)

Antibiotics:~ Destroys cell wall of bacteria~ Creates holes in the cell walls

Sir Alexander Fleming1928 - discovered Penicillium notatum

Air-Born

Air-Born Bacteria

Reproduction

Asexual• Binary Fission

– Cell division

• Rapid - 20 min.

Sexual• Conjugation –

exchange genetic material

• Pili/pilus - bridge

Binary Fission: Asexual Reproduction

Conjugation - Sexual Reproduction