Characteristics of Living Things• Living things are made of cells.• Living things reproduce• Living things are based on genetic code• Living things grow and develop• Living things obtain and use energy• Living things respond to the environment• Living things maintain a stable internal

environment• Living things change over time

Today’s Modern Kingdoms• Prokaryotes-

simple cells1. Eubacteria-

“normal” bacteria found everywhere

2. Archaebacteria- unusual bacteria found in hot springs, brine pools and mud

• Eukaryotes- complex cells with nucleii3. Fungus- mold,

mushrooms, etc. decomposers

4. Protists- microscopic “left over” group

5. Plants- make food

6. Animals- consumers of food

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BacteriaHow is the world we live in impacted by things that you

can’t see?

Health & Social Education

Bacteria• Bacteria are living things that are

neither plants nor animals. – Two Kingdoms: Eubacteria &

Archaebacteria– Prokaryotes – all bacteria. have no

nucleus or complex organelles

Salmonella typhimurium (invading human cells)

E. coli

E. coli

Archaebacteria vs. Eubacteria• Live in extreme

environments

• Chemically different

• Cell wall lacks peptidoglycan (carbohydrate)

• Live in non-extreme environments

• Chemically different

• Cell wall contains peptidoglycan (carbohydrate)

Where???

• Eubacteria live almost everywhere:– Fresh water– Salt water– Land– On & within your body!

Archaebacteria• Chemically different from

eubacteria– Lack peptidoglycan cell

walls• DNA sequences differ

from eubacteria• “Extremophiles”

– Can live in extremely harsh environments

– Acidic pH, temperature, saline, anaerobic(no oxygen)

Yellowstone Geyser

Disease Caused by Bacteria• Pathogens-

disease causing agents

• Two ways bacteria cause disease

– 1. Digesting cells– 2. Produce toxins

Preventing Bacterial Disease

• Antibiotics: block the growth and reproduction of bacteria(not viruses)

• Vaccines: weakened pathogens injected into body to produce resistance

Methods used to control bacterial growth…

1. Sterilization by heat-great heat

2. Disinfectants-chemical solutions that kill pathogenic bacteria

3. Food storage and processing-refrigeration, canning, preservatives

4. Dehydrate food

Importance of Bacteria• Decomposers

– Recycle nutrients from dead organisms back into the ecosystem

– Ex: A tree dies; bacteria attack and digest dead tissue, break it down into simpler material and return it to the soil.

Human Uses of Bacteria1. Production of

foods and beverages

2. Oil spill clean up

3. Removal of waste and poison from water

4. Mining of minerals

5. making essential vitamins in body

6. Production of medicines and chemicals

Where is good bacteria found?1. Digestive tract2. Skin3. Mouth4. Urinary tract5. Genital areas

Bacteria Reproduction•Binary Fission:

–1.Doubles in size –2.Doubles DNA –3.Splits into two

•Conjugation: –1.Bridge forms between two cells –2.Genes move from one cell to another

•Endospore Formation: –1.Thick wall within bacteria forms to protect its DNA –2.Cell is now a spore, and goes into hibernation until more favorable conditions return

Growth Rates• Given good

growing conditions, a bacteria can grow and divide at astonishing rates.

• If the environment is optimal, bacteria cells can divide as often as every twenty minutes.

Typical Eubacterial Cell• Bacteria

(prokaryotes) are simpler than eukaryotes

• Cell wall: – Protects from injury– Determines shape– Made of

peptidoglycan (carbohydrate molecules linked by proteins)

Shapes of Bacteria• Spiral-shapedSpirilla

• Sphere-shapedCocci

• Rod-shapedBacilli

Name the shape!1 2

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