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85 Cards in this Set
- Front
- Back
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what happened 13.7 billion years ago |
earth formed from an atom to a galaxy |
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which elements formed stars |
helium and hydrogen |
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what is the importance of supernovas |
created new elements, stars hitting each other |
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What is the importance of the collision of a Mars-sizedobject with earth 4.5bya? |
creates an orbital around earth, slow it down and makes it steady, longer days, no drastic climate, seasons |
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evolution of life |
monomers polymers protocells |
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what did the air contain in black earth |
h20, ch4, nh4, h2 |
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conditions of black earth |
air different no ozone layer to block uv rays volcanic activity energy from lots of lightening torrential rain |
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oceans were a primordial soup of |
ammonia, phosphate, nitrogen and carbon |
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miller-urey |
atmosphere contained CH4, No3, h2, h20 electrodes stimulated lightening obtained organic compounds (amino acids) collected in cool water |
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primordial soup hypothesis |
molecules washed into ocean accumulated in thick organic soup formed organic monomers |
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Iron-Sulfer hypothesis |
gases from thermal vents iron and nickel sulfide around vents to catalyze organic compounds from inorganic |
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extrasterestial orgins hypothesis |
organic molecules carried to earth by meterorites |
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clay |
extensive surface allows for organic molecules to form |
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protein-world hypothesis |
proteniods formed in dried puddles microspheres |
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microsphere have |
competitive advantage |
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RNA-world hypothesis |
RNA was probably the first hereditarymaterial. |
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evidence rna was first |
- Short polymers of ribonucleotides can be synthesized abioticallyin the laboratory and can self-replicate (mutations lead to evolution) -both genotype and phenotypes that interacts with ribozymes, store codee for other molecules/structures , can assemble other structures -viruses store RNA today, dna is genetic |
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micelles |
oil naturally forms intodroplets in water, can form largervesicles; fatty acids |
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liposome |
Micelles naturally form membranearound protein microspheres |
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protocell |
lipid that has life-like features structure with an outermembrane • Boundary allows maintenance ofconditions, selectively permeable |
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• Membrane-first hypothesis: |
membranes protected molecules andallowed them to react |
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Characterisitics of life |
order,reproduction, growth/development, energy utilization, homeostasis, evolutionary adaptation |
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Bacteria cell |
The DNA of bacteria is containedin a circular chromosome, foldedinto many loops. Bacteria often have small circlesof additional DNA called plasmids Bacteria have both aplasma membraneand a cell wall. |
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prokaryotes time period |
3.5- 2 BYA precambrian time |
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oldest fossils of microorganisms |
3.5 billon years ago embedded in rocks in western austrailia stromatolites |
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Microbial mats |
highly saline orperiodically dry environments |
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layers of microbial mats |
blue-green- cyanobacteria, oxygen rich mat, photosynthesis occurs purple-anoxygenic photosynthetic bacteria, h2, hydrogen sulfide, iron as electron donors black- no oxygen or light, anaerobic respiration and fermentation |
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Some prokaryotes can obtainenergy |
from chemicals not the sun |
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• Chemoautotrophy |
uniquelyprokaryotic metabolism of H2,H2S, and Fe+ to generate ATP The base of the foodweb arounddeep-sea hydrothermal vents More diverse and abundant thansurrounding areas due to thethriving community ofmicroorganisms |
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Oxygenic photosynthetic bacteria harness |
the sun's energy and produce oxygen as by product |
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Cyanobacteria |
rapidly added abundant oxygen to the atmosphere, changing its composition |
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By 2 bya, the presence of O2 made |
most environmentsunsuitable for anaerobic prokaryotes created ozone layer : uv helped form organic molecules, but would destroy land-dwelling organisms |
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With oxygen, more efficient |
aerobic respiration candevelop |
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More energy means |
more complexity |
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prokaryotic phylogency |
Not a tree, but a series ofbranches that diverge andcome back together Horizontal transfer of atleast 85% of all genes inbacterial genomes Rampant gene exchangealmost dooms the creationof a prokaryotic phylogeny |
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Genes are readilyexchanged via |
horizontal gene transfer |
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Genes can diverge but |
can reside in same organism |
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Domains |
geneticallydetermined by George Foxand Carl Woese in 1977 . Bacteria and Archaea |
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Bacterial genomes are |
small and lack the noncoding DNA characteristic ofeukaryotic chromosomes. |
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what size are bacterial genomes |
small, rapid reproduction in good conditions |
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Three types of DNA transfer |
1. conjugation, transformation, transduction |
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conjugation |
dna from donor cell is transfered via pilus that brings donor to recipient and brings cells together , dna passes through a small opening |
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transformation |
dna is released into the environment by dead cells and recipent cell takes it in |
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transduction |
transfered by a virus (bacteriophage) |
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three shapes |
1. coccus (spherical) 2. Bacillis (rod-shaped) 3. Spirillum (spiral) |
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gram - |
pink capsule surrounding it (Lipopolysaccharides) resistant to antibiotics |
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gram + |
purple thick cell wall susceptible to antibiotics |
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Parasitism |
relationship between species where onespecies (parasite) benefits at the expense of the other(host) |
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Parasitic Bacteria are considered |
pathogens |
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Some bacteria live within |
host awaiting opportunity to causedisease |
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• If body surface is breached by particular bacteria |
bacteria Infection rarely leads to infectious disease |
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other factors determine outcome of infection |
such as the route of entry, the number of infectious bacteria,and (most importantly) the status of the host defenses |
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bacteria uniqueness |
• Bacteria show more metabolic diversity than all other kingdomscombined • Every kind of food eaten by any other form of life can be eaten by somespecies of bacteria Some nutrients can only be used by bacteria and not by any other formof life Bacteria can do photosynthesis dozens of different ways versus plantsor algae which have only one type of photosynthesis • Bacteria can produce energy (respiration) in 100’s of different waysversus only 1 way for plants and animals |
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all life requires |
food for survial |
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2 main sources of food for survival |
building blocks energy |
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building blocks |
elements and molecules construct cell parts |
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energy source |
powers all metabolism and everything cell does |
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what can be eaten by bacteria |
every natural and human made chemicalcan be eaten minerals in rocks, acids, pesticides, herbicides |
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Most bacteria are |
heterotrophs |
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chemohetrotroph |
energy source- organic compounds c source- organic compounds e-coli |
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photohetrotroph |
energy source- ligh c source- organic compounds heliobacteria (purple layer) |
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. Photoautotrophs |
energy source light carbon source-co2 cyanobacteria |
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Chemoautotrophs: |
energy source- inorganic compounds carbon source- co2` |
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autotrophs |
can make their own sugarsand organic molecules from small inorganic molecules using some otheroutside energy source |
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• Earth system has four parts: |
Atmosphere• Hydrosphere• Lithosphere• Biosphere |
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Biogeochemical cycles |
the chemical interactions (cycles) thatexist between the 4 spheres; driven by abiotic and bioticprocesses |
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primary production |
C,N, P, H2O, |
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• Bacteria can get carbon from a wide variety of sources: |
Largely important as decomposers (Fermentation, Anaerobic Respiration) Also important in nutrient utilization in animals |
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Gut Flora |
within animals digest molecules indigestible by the animalitself in exchange for habitat |
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Primary producers assimilate |
usable N into biological system (Nitrate* and ammonia) |
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consumers and nitrogen |
acquire N from producers, |
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and decomposers and nitrogen |
return organisms’ N to ground asammonia |
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Nitrogen fixation |
N2Ammonia (NH3, somewhat usable form) |
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nitrify nitrification |
ammonia to best form for producers (Nitrate) NO-3 |
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plant roots |
have a symbiotic relationship with thesenitrogen fixing bacteria! |
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N can be fixed in low-O2 conditions: plant creates growthchambers on root called |
root nodules mostly legumes |
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bacteria and archaea |
RNA, cell walls, cell membranes |
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rna differnce |
dna transciption- archea uses RNA polymearse and ribosomes antibiotics- ineffective at targetting archea, translation difference |
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cell walls |
Cell WALLS vary from species tospecies, and all lackpeptidoglycan (bacteria),cellulose (plants), or chitin(fungus) |
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cell membranes |
Ether lipids are more stable thanester lipids Some have cyclopentane rings fordecreased fluidity in hightemperatures Some have more double bonds inlipids for increased fluidity at lowtemperatures |
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• Extremophiles |
organisms thriving at extreme environments |
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Hyperthermophiles |
: must grow and reproduce at 80○C or greater |
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Halophiles |
must grow and reproduce inhighly saline environments (more thanoceans) |
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• Acidophiles |
must grow and reproduce inhighly acidic environments |
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Methanogens |
earth’s only biologicalsource of methane; anaerobic cattle rumen |
