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51 Cards in this Set
- Front
- Back
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When are bacteria believed to have come into existence? |
About 3.5-3.8 billion years ago |
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Where can bacteria be found? |
Everywhere, everyday places, hot springs, volcanoes, dead sea, antarctica, Chernobyl, places with no O2, human digestive system |
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When is the earth and moon believed to have come into existence? |
4.54 billion years ago |
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What is the earth believed to have been like then? |
Strong radiation from the sun, very little oxygen, very high temps, extreme volcanic activity |
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What is a microbial mat? |
A multilayered sheet of prokaryotes that is a few centimeters thick |
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What holds these mats together? |
A glue like substance called extracellular matrix that is secreted by these cells |
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Where was the first believed to have been? |
By hydrothermal vents, bottom of the ocean |
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How did it obtain energy? |
By breaking down chemicals by hydrothermal vents |
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When is it believed that the first photosynthetic prokaryotes evolved? |
3 billion years ago |
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What are Stromatolites? |
The fossil of microbial mats |
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What does anoxic mean? What type of organisms can survive in this type of condition? |
No pure oxygen present. Anaerobic organisms. |
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What is believed to be the progression of evolution in prokaryotes? |
Chemotrophs were first. Got their energy from chemicals. Phototrophs appeared next. Got their energy from sunlight.Cyanobacteria evolved a billion years later and began to release oxygen and oxygenate the atmosphere. O2 naturally converted to O3, provided an ozone layer that allowed life on land bc of providing protection against radiation. |
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Why is cyanobacteria important? |
provides o2 |
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What are extremophiles? |
Bacteria that are adapted to grow in extreme conditions. |
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Acidophile |
acidic conditions |
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Alkaliphiles- |
basic conditions |
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Thermophiles- |
high temps |
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Hyperthermophiles- |
extremely high temperatures |
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Psychrophiles- |
low temperatures |
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Halophiles- |
high salt concentration |
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Osmophiles- |
high sugar concentration |
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What does it mean to culture bacteria? |
To grow bacteria in a lab setting |
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How much bacteria is culturable? |
Less than one percent |
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What does VBNC mean? Can these bacteria become active again? How? |
Viable-but-not-culturable. Living a dormant life. Yes when they have the right conditions. “Resuscitation” |
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What is a biofilm? |
When multiple bacterial cells live in a community with one another on a solid surface |
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How is different than a microbial mat? |
Simpler, always on a solid surface |
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What are examples of biofilms? |
Plaque on your teeth, clogged drains, household surfaces |
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Why are they better than planktonic bacteria? |
Planktonic bacteria are individual bacteria. They are weaker. Biofilms can survive antibiotics |
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What do all cells have? |
Cell membrane, cytoplasm, DNA, ribosomes |
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What shapes are most common in prokaryotes? |
Sphere, circle shapes. Bacilli, rod. Spirilli, spiral. |
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What are the parts of these prokaryotic cells |
Ribosome- make proteins. Cell membrane- regulate what enters and leaves. Cell wall- structure and protection. Flagellum- locomotion. Pilus- attach to surfaces. Capsule-attach to surface, prevent dehydration, resist immune response. DNA- circular double stranded in nucleoid region. NO NUCLEUS. Plasmid- extrachromosomal DNA. |
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How are prokaryotes different than Eukaryotes? |
They don’t have membrane bound bodies |
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How is the plasma membrane different in Archaea and Bacteria? |
Bacteria have a bilayer. Archaea sometimes have one layer. Archaea have branches that come off their fatty acids. The bind between the fatty acid tails and the glycerol are different. Archaea- fatty acid tail connect on bilayer, bacteria doesn’t |
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How is the cell wall different in Archaea and Bacteria? |
Bacteria cell walls have peptidoglycan |
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How is gram positive bacteria different than gram negative? |
Gram positive- appear to have thicker wall (more peptidoglycan) Gram negative- wall appears thinner, extra membrane on the outside of the cell wall |
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How do prokaryotes reproduce? |
Assexually through binary fission |
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What three ways can they gain genetic diversity? |
transformation, transduction, conjugation |
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Why can bacteria evolve so quickly? |
They have random mutations. The generation time of bacteria is usually very short. |
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What macronutrients do bacteria need? |
CHNOPS |
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Carbon- |
in 50 percent of biomolecules |
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Nitrogen- |
nucleic acids, proteins |
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Hydrogen and oxygen- |
water and organic compounds |
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Phosphorous- |
phospholipids, nucleotides |
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What micronutrients do they need? |
Iron |
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Phototroph |
energy from the sun |
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Chemotroph- |
obtain it from breaking down chemical compounds |
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Chemoorganotrophs- |
breaking down organic compounds |
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Chemolithotrophs- |
inorganic compounds |
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How can they obtain carbon? |
From air or water (always CO2- gas) |
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How do prokaryotes help in the carbon cycle? |
By helping return the carbon to the atmosphere as CO2 |
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How do prokaryotes help in the nitrogen cycle? |
Take some N2 and turn it into a usable form for plants. Others make N2 out of ammonia |
