Characteristics of Living Things - PowerPoint PPT Presentation

• 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

Eubacteria- “normal” bacteria found everywhere

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

Eukaryotes- complex cells with nucleii

Fungus- mold, mushrooms, etc. decomposers

Protists- microscopic “left over” group

Plants- make food

Animals- consumers of food

2

1

BacteriaHow is the world we live in impacted by things that you can’t see?

Health & Social Education

• 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

• Bacteria (prokaryotes) are simpler than eukaryotes
• Cell wall:
• Protects from injury
• Determines shape
• Made of peptidoglycan (carbohydrate molecules linked by proteins)

• Spiral-shapedSpirilla
• Sphere-shapedCocci
• Rod-shapedBacilli

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

• 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)

Chemically different

Cell wall lacks peptidoglycan (carbohydrate)

Live in non-extreme environments

Chemically different

Cell wall contains peptidoglycan (carbohydrate)

1

2

3

4

5

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

Spore 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

• 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.

• Pathogens-disease causing agents
• Two ways bacteria cause disease
• 1. Digesting cells
• 2. Produce toxins

• 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…

Sterilization by heat-great heat

Disinfectants-chemical solutions that kill pathogenic bacteria

Food storage and processing-refrigeration, canning, preservatives

Dehydrate food

• 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.

Oil spill clean up

Removal of waste and poison from water

Mining of minerals

making essential vitamins in body

Production of medicines and chemicals

• Digestive tract
• Skin
• Mouth
• Urinary tract
• Genital areas