Cosmology Flashcards
What does CHNOPS stand for?
carbon, hydrogen, nitrogen, oxygen, phosphorous, sulfur
What process turns quarks into hydrogen and helium atoms?
expansion/cooling from the big bang
How does hydrogen become helium?
2 hydrogen nuclei fuse and release energy (heat)
What are the steps to forming carbon from hydrogen? What about oxygen?
H + H = He (4)
He (4) + He (4) = Be (8)
Be (8) + He (4) = C (12)
C (12) + He (4) = O (16)
What are nebulas?
gaseous carbon and oxygen rich clouds of elements surrounding a star
Briefly describe the life stages of a sun
1) hydrogen condenses to form a star core
2) main stage = continuous burning of hydrogen
3) hydrogen core expands as a new helium core forms
4) star enlarges to become a red giant, a new carbon core forms
5) star collapses and releases gases, forms a white dwarf with a pure carbon core
What elements likely formed during the big bang?
- hydrogen
- helium
- beryllium
- lithium
- boron
What is nucleosynthesis?
the formation of atomic nuclei (from He to Fe)
process ends with Fe as cooling becomes heating due to gravity and expansion becomes implosion
What are the two fate pathways for a stellar nebula?
1) nebula –> star –> red giant –> planetary nebula –> white dwarf
2) nebula –> massive star –> red supergiant –> supernova –> neutron star or black hole
What were the 3 big transitions in evolution?
1) putting replicating material into protocells
2) binding replicators into chromosomes
3) creation of prokaryotic systems
What two kingdoms dominated the Precambrian period?
bacterian + archaea
In what period did early life first arise?
early archaean (~3.8 BYA)
What characteristics define life?
- carbon based
- membrane bound (cellular)
- metabolizes (energy) with ATP
- reproduces with variation (ability to evolve)
What are the 3 potential hypotheses for the origins of life?
- panspermia
- hydrothermal vents
- prebiotic soup
Explain Miller-Urey’s life spark experiment
- system mimicked early earth conditions (water, electricity, atmosphere)
- electricity provided energy for conversion of simple molecules into amino acids
What is the Oparin-Haldane model?
1) monomers become polymers
2) polymers arrange and are able to catalyze reactions (enzymes) and store information (nucleotides)
3) introduce membranes and an energy source to form a living cell
What are the 3 abiogenesis hypotheses?
1) RNA first - early RNA that could catalyze and store information were bound by membranes
2) metabolism first - proteins and other molecules capable of energy conversion got attached to charged molecules + were bound by membranes
3) membrane first - spontaneously forming phospholipid protocells trapped molecules like RNA
Briefly explain the primordial soup concept
- early elements exposed to energy sources (i.e lightning) formed monomers in aquatic environments
- monomers became concentrated as a result of evaporation etc. in shallow water
- monomers within the concentration formed polymers through reactions and ultimately formed complex structures and life forms
Briefly explain the RNA world concept
- nucleotides arranged and formed RNA
- RNA capable of self replicating as well as binding to itself to form ribozymes (capable of catalyzing other reactions)
How is chemiosmosis hypothesized to aid in the establisment of life?
- forms ATP through an electrochemical gradient from proton pumps
- ATP needed for life
Briefly describe the hydrothermal vent hypothesis
- white smokers with tolerable temperatures and rich in iron/sulfur
- abundant in CHNOPS, nitrogen and phosphorous to form AA and nucleotides
- uses electrochemical gradients
What is the panspermia hypothesis?
- life arrived from earth from somewhere in the universe
- does not explain how the life originated
- organic life forming molecules may have arrived on meteorites (chondrites)
What is the name of the meteorite where an abundance of organic molecules have been found?
Murchison meteorite
What is LUCA?
last universal common ancestor
had to some extent a universal genetic code (DNA/RNA), used ribosomes, used ATP
Which domain is the eukaryotic LUCA theorized to belong to? Why?
- archaea
- both are not photosynthetic
- is capable of transcribing DNA into RNA
- thermophilic (aligns with hydrothermal vent theory)
What is the difference between horizontal and vertical gene transfer?
horizontal = gene transfer done through absorption of material in the environment, likely how RNA-based life functioned
vertical = gene transfer through inheriting from parents, shared between all kingdoms (bacteria/archaea/eukaryotes),
threshold between horizontal and vertical is the Darwinian threshold
What are stromatolites?
- rocks created from microbial colonies of cyanobacteria forming mats of sediment and decaying matter
- fossil record suggests they are some of the earliest bacterial life
What are viruses?
- life-like (not living)
- contain RNA
- parasitic (require a host)
- contains spike proteins to bind to host
How are influenza viruses named?
H = hemagglutinin, # = mutation
N = neuraminidase, # = mutation
What do hemagglutinin and neuraminidase do?
hemagglutinin = recognizes binding sites on host cells, the ‘entry’ of the virus
neuraminidase = detaches virus from host cell after replicating, the ‘exit’ of the virus
What does viral reassortment do?
- combines genetic material of two viral strains infecting the same cell and forms a new viral strain
- new strain can have different infection patterns than its parent strains (i.e spread from swine to human)
- hosts will not have antibodies against new strains and will be easily infected
