Life in the Universe quiz 6/7

how long has life been on earth

4 billion years

3 things we need for life

liquid water, energy source, raw ingredients (organic compounds)

where

shallow ponds (Darwin suggested) and early atmosphere

ozone

protects us from UV rays

UV rays

while out simple early life

deep sea volcanic vents

protected from Uv rays, current idea of where life started

miller-urey

shows it is easy to get amino acids/DNA bases

stromatolites

structurally/chemically similar to living stromatolites, implication of photosynthesis

microfossils

more challenging to confirm biological origin

carbon isotopes

supports biological origin of microfossil and stromatolites, looks at the ratio of isotopes

miller urey experiment

demonstration that organic building blocks can form easy and naturally

RNA world

RNA is simpler then DNA, can hold hereditary information, catalyze chemical reactions, and form naturally through clay catalysts

DNA

copies of information better then RNA, can replicate better

how

chemical evolutions turns to biological evolution

panspermia

life on earth came from elsewhere

common ancestor

98% DNA shared with chimpanzees, liquid water, 20 animo acids, same elements, cells, carbon based, left handed

first requirement

building blocks of life

second requirement

energy (from the sun is the primary source), weakens with more distance

sunlight

“inverse square low”

third requirement

liquid plays 3 roles

3 roles liquid plays

dissolves chemicals, transport into/out of/within cells, metabolic reactions

water

the best liquids, broad/relatively high liquid temperature range, ice floats, charge separation facilitates biochemistry