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7.2 Bacteria

I. What are bacteria?a. Bacteria are the only prokaryotes

i. Bacteria-single, prokaryotic cellii. Only prokaryotes(no nuclei)

b. Where do bacteria live?i. On/in almost every material & environment on Earth

1. Soil, water,& air2. Coldest of Artic & boiling waters near undersea volcanoes

c. 1 or 2 kingdoms of bacteria?i. Some scientists group in Kingdom Monera

ii. Some scientists group bacteria in Kingdom Archaebacteria and Eubacteria1. Archaebacteria-extreme environments2. Eubacteria- almost anywhere else &different chemical makeup than

Archaebacteriaiii. Both are prokaryotic

II. Size and Shape of Bacteriaa. How big are bacteria?

i. 1.5 million times smaller than average personii. Measured in micrometers

1. I micrometer= one-millionth of a meterb. Shapes of bacterial cells

i. Rod-shaped =Bacilliii. Ball-shaped=Cocciiii. Spiral-shaped=Spirillaiv. Some exist as individuals, pairs, chains, or clusters

III. Movement and feedinga. How bacteria move

i. Some move using flagella to propel through liquid environmentsii. Some have slimy layer on outside to slide over surfacesiii. Some are just carried by movement of air or liquidiv. Some are transferred through surface to surface

b. Some bacteria make their own foodi. Photosynthetic bacteria make their food from sunlight and carbon dioxide

1. Also they produce oxygen2. Cyanobacteria- Photosynthetic

ii. Bacteria that live in harsh environments produce food without sunlight. Theyuse chemicals to produce their food instead of energy from the sun

1. Chemosynthesisc. Some bacteria get their food from outside

i. Absorb food from material they live on/in

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1. Break down dead organismsIV. Bacteria and the beginning of life on Earth

a. Bacteria were the first organismsi. Single-celled prokaryotes< than 3 billion yrs. Old

ii. Anareobic Bacteria- dont require oxygen for cellular respirationb. Bacteria increased oxygen in Earth atmosphere

i. Some bacteria developed ability to use photosynthesis1. Cyanobacteria- one of the first photosynthetic bacteria

ii. Aerobic bacteria use oxygen for cellular respirationc. Eukaryotic cells developed from prokaryotic cells

i. Smaller prokaryotes were engulfed by larger prokaryotesii. Smaller cells began to survive by living inside largeriii. Eventually become organelles

V. The importance of Bacteriaa. Bacteria and Industry

i. Yogurt and cheese are made with certain types of bacteriaii. Some drugs are made with the help of bacteriaiii. Sewage treatment plants use bacteria to break down waste productsiv. Other bacteria are used in mining and to clean up oil spills

b. Symbiosisi. Bacteria and the organism both benefit

1. Called mutualismc. Life on Earth depends on bacteria

i. Plants need nitrogen to make amino acidsii. Bacteria are natures recyclers

d. Bacteria and Antibioticsi. Bacteria causes diseases& illnesses

1. They are treated by antibioticsa. Antibiotics kill bacteria without harming your own cells