characteristics of living things
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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 - PowerPoint PPT PresentationTRANSCRIPT
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
1 2
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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