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Lecture 10

BIO SCI 94 Lecture 10: Ch. 29 Bacteria and Archaea Part 1Premium

Biological Sciences
Course Code
Brad Hughes

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Bacteria, Archaea-2 largest branches on tree of life
Third largest branch/domain-Eukarya(the eukaryotes)
Members of bacteria/archaea nearly all unicellular, all are prokaryotic
Prokaryotic-lack a membrane bound nucleus
Bacteria/Archaea recognized by:
Type of molecules which make their cell walls/plasma membranes
Machinery used to transcribe DNA/translate mRNA into proteins
Biological Impact
Lineages in Bacteria/Archaea ancient, diverse, abundant, ubiquitous
Oldest bacteria fossil 3.5 billions years old
1.7 billions years later-Eukaryotes appear
5000 bacteria/ archaea discovered, millions more left to name/describe
1000+ species in human intestine
700 species in human mouth
Microbes-microscopic organisms
Most bacteria/archaea
Most unnamed/undescribed
10 trillion cells form human body
10 times the number of bacterial/archaeal cells than human cells in body
1 teaspoon of soil=billions of microbes
1 milliliter of seawater=10,000 marine archaea
Bacteria/archaea found 1600 meters beneath world’s ocean
Estimated number of living prokaryotes is over 5x1030
Lined up and chained, chain will be longer than milky way
Volume of living material-bacteria/archaea dominant life forms
Habitat Diversity
Bacteria/archaea live almost everywhere
Found in depths of 10,000m and temperatures from 0-121 C
New phyla of bacteria/archaea discovered in field of microbiology
Microbiology-study of microbes
Causes disease
Common in human gut, used to produce foods and alcohol
Cyanobacteria-produce oxygen in atmosphere
Highly abundant, 80 species discovered
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