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BACTERIA

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Bacterial colony

Figure 4.1

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5Bacteria 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 compared 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• Adapted to survive where no other organisms can.• Grouped based on:

– Structure, physiology, molecular 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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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

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Bacillus bacteria are rod shaped

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Coccus bacteria are

sphere shaped

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Spirillium bacteria have a corkscrew shape

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BACTERIA PICS

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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.

– can produce exotoxins made of protein

• Gram-negative do not retain stain and take second pink stain instead.

– can produce endotoxins made of lipids and carbohydrates

– Watch it happen! http://youtu.be/aJpZzF3h3kc

28No 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 heterotrophi

c bacteria digest oil -- remember

oil is partially decayed plant and

animal cells

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BACTERIA REPRODUCES binary FISSION

First the chromosomal DNA makes a copyThe 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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CONJUGATION

Exchange DNA through Exchange DNA through Conjugation tube/pilusConjugation tube/pilus

http://youtu.be/EtxkcSGU698

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Transformation and Tranduction

• Transformation: Bacterial cell takes in DNA from external environment– http://youtu.be/eovTbQgan5M

• Transduction: Virus obtains DNA from Bacterial host

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Examples

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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

CHOLERA

DENTAL CARIES

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ROCKY MOUNTAIN Spotted Fever tickborne disease caused by the bacterium Rickettsia rickettsi

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LYME DISEASE

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SALMONELLA

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STREP THROAT

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TUBERCULOSIS