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Anatomy of a virus
Viruses consist of a capsid as well as DNA or RNA.
How HIV infects a host.
1. virus membrane binds to host cell membrane, opens it and injects RNA & enzymes
2. reverse transcription changes RNA to DNA and is injected into nucleus.
3. New envelope is formed and it is released to infect other cells.
How do viruses become pandemics?
-high mutation rates
-jumping between host species
List 6 characteristics of life.
1. Levels of organization
2. Acquire and use energy
4. Respond to environmental stimulus
5. Self reproducing
Maintaining a stable internal environment
Strata (in terms of fossils)
Distinct layers of sedimentary rock
Measuring of strata and fossils in order to find which order fossils came in. (but can't actually tell how long ago it was created)
The decay rate of radioactive isotopes in fossils or rocks can be used to tell when fossil was created. C-14 (nitrogen-14(used in photosynthesis) begins to decay at death at a constant rate.
When 50% of atoms in a radioactive substance have decayed. C12:C14 ratio can be used to date fossils (C12 doesn't decay)
don't require oxygen to live
-live in animals guts and rotting oxygen free substrates.
first bacteria to create oxygen through photosynthesis. causing other prokaryotes to adapt to an oxygen rich atmosphere.