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BACTERIA

Biology Chapter 18.2

2Bacteria are very small

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This is a pore in human skin and the yellow spheres are bacteria

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Bacteria are very small compar-ed to cells with nuclei

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Bacteria compared to a white blood cell that is going to eat it

Bacteria

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Clean skin has about 20 million bacteria per square inch

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Evolution/Classification Most numerous on Earth Most Ancient Microscopic Prokaryotes Evolution has yielded many species

adapted to survive where no other organisms can.

Grouped based on: Structure, physiology, molec. Composition

reaction to specific types of stain. Eubacteria= Germs/bacteria Archaebacteria

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Kingdom Archaebacteria First discovered in extreme environments Methanogens: Harvest energy by

converting H2 and CO2 into methane gas Anaerobic, live in intestinal tracts

Extreme halophiles: Salt loving, live in Great Salt Lake, and Dead sea.

Thermoacidophiles: Live in acid environments and high temps. Hot Springs, volcanic vents

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Volcanic vents on the sea floor

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Chemosynthetic bacteria use the sulfur in the “smoke” for energy to make ATP.

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The red color of this snow is due to a blue-green bacteria

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Kingdom Eubacteria Can have one of three basic shapes

1.Bacilli – rod-shaped2.Spirilla – spiral-shaped3.Cocci – sphere-shaped

Streptococci – in chains

Staphylococci – grape-like clusters

SHOW ME

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BACTERIA PICS

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Bacillus bacteria are rod

or sausage shaped

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Coccus bacteria

are sphere or ball

shaped

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Spirillium bacteria have a corkscrew shape

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Diplo-bacteria occur in pairs,

such as the diplococcus

bacteria that causes

gonorrhea

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Staphylo - bacteria occur in clumps, such

as this staphylococcus bacteria that

causes common infections of

cuts

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Strepto- bacteria occur

in chains of bacteria, such

as this streptococcus bacteria that causes some types of sore

throats

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Spirillium bacteria

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Diplobacillus bacteria

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Streptococcus bacteria

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Staphylococcus bacteria

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The tip of a needle

The red and yellow dots are bacteria

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Gram Stain Gram-positive retain stain and appear purple

Have thicker layer in cell wall. Gram-negative do not retain stain and take

second pink stain instead.Phylum Shape Motility Metabolism Gram

reacionCyanobacteria Bacilli,

CocciGliding, some non-motile

Aerobic, photosynthetic autotrophic

Gram-negative

Spirochetes Spirals Corkscrew Aerobic, and anaerobic; heterotrophic

Gram-negative

Gram-Pos Bacilli, cocci

Flagella; some non-motile

Aer/anaer.; heterotrophic, photosynthetic

Mostly gram-positive

Proteobacteria Bacilli, cocci, spiral

Flagella; some non-motile

Aer/anaer.; heterotrophic, photosynthetic autotrophic

Gram-negative

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STRUCTURE OF BACTERIAStructure Function

Cell Wall Protects and gives shape

Outer Membrane

Protects against antibodies (Gram Neg. Only)

Cell Membrane

Regulates movement of materials, contains enzymes important to cellular respiration

Cytoplasm Contains DNA, ribosomes, essential compounds

Chromo-some

Carries genetic information

Plasmid Contains some genes obtained through recomb.

Capsule & Slime Layer

Protects the cell and assist in attaching cell to other surfaces

Endospore Protects cell agains harsh enviornments

Pilus Assists the cell in attaching to other surfaces

Flagellum Moves the cell

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No Nucleus-DNA in Cytoplasm

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Nutrition and Growth Heterotrophic or Autotrophic Some are Photoautotrophs – Use sunlight for Energy Some are Chemoautotrophs. Many are Obligate Anaerobes.

Oxygen = Death Ex. Clostridium tetani – Tetanus

Some are Faculatative Anaerobes With or without Oxygen

Ex. Escherichia Coli Some are Obligate Aerobes

Ex.) Mycobacterium tuberculosis Temperature requirements

Some are Thermophilic, Some prefer acidic envmt.

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These heterotrophic

bacteria digest oil --

remember oil is partially

decayed plant and animal

cells

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REPRODUCTION IN

BACTERIA

(please add to notes)

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No Nucleus-DNA in Cytoplasm

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BACTERIA REPRODUCES BY FISSION

First the chromosomal DNA makes a copy

The DNA replicates

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NEXT THE CYTOPLASM AND CELL DIVIDES

The two resulting cells are exactly the same

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In addition to the large chromosomal DNA, bacteria have many small loops of DNA called Plasmids

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Genetic Recombination Nonreproductive Methods bacteria can acquire new

genetic material.

Characteristic Transformation Conjugation Transduction

Method of DNA Transfer

Across cell wall and cell membrane of recepient

Through a conjugation bridge between two cells

By a virus

Plasmid transfer

Yes Yes Not likely

Chromosome transfer

No Sometimes No

Antibiotic resistance acquired

Yes Yes Sometimes

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TRANSFORMATION

This plasmid of DNA is new to the bacteria – added by transformation! Produces the glowing protein

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CONJUGATION

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TRANSDUCTION

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Bacteria and DiseaseDisease Pathogen Areas

affectedMode of transmission

Botulism Clostridium botulinum Nerves Improperly preserved food

Cholera Vibrio cholerae Intestine Contaminated water

Dental Caries Streptococcus mutans, sanguis, salivarius

Teeth Environment to mouth

Gonorrhea Neisseria gonorrhoeae Urethra, fallopian

Sexual contact

Lyme disease Berrelia burgdorferi Skin, joints Tick bite

Rocky Mountain SF

Rickettsia recketsii Blood, skin Tick bite

Salmonella Salmonella Intestine Contaminated food, water

Strep throat Streptococcus pyogenes URT, blood, skin

Sneezes, coughs, etc.

Tetanus Costridium tetani Nerves Contaminated wounds

Tuberculosis Mycobacterium tuberculosis Lung, bones

coughs

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Some bacteria cause diseases --Disease causing bacteria are call

PATHOGENIC

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Helicobacter pylori

is the pathogenic bacteria that can

causes ulcers

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Leprosy is a bacterial

infection that decreases

blood flow to the

extremities resulting in

the deterioration of toes, ears, the nose and the fingers.

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BOTULISM

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CHOLERA

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DENTAL CARIES

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ROCKY MOUNTAIN SF

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LYME DISEASE

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SALMONELLA

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STREP THROAT

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TETANUS

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TUBERCULOSIS

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Common AntibioticsAntibiotic Mechanism Target bacteria

Penicillin Inhibits cell wall synthesis Gram Positive

Ampicillin Inhibits cell wall synthesis Broad spectrum

Bacitracin Inhibits cell wall synthesis Gram Positive – Skin Ointment

Cephalosporin Inhibits cell wall synthesis Gram Positive

Tetracycline Inhibits Protein Synthesis Broad spectrum

Streptomycin Inhibits Protein Synthesis Gram Neg. tuberculosis

Sulfa drug Inhibits cell metabolism Bacterial meningitis, UTI

Rifampin Inhibits RNA synthesis Gram Pos., some Neg.

Quinolines Inhibits DNA Synthesis UTI

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Some Final Information Because antibiotics have been overused,

many diseases that were once easy to treat are becoming more difficult to treat.

Some Bacteria are Useful Ex.) Producing and Processing food Breaking down dead organic material Make unripened cheese like ricotta and

cottage by breaking down the protein in milk.