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37 Cards in this Set
- Front
- Back
What are the minimal requirements for life?
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catalysis, response to the environment, growth, metabolism, heredity
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What was the first molecule of life? DNA or RNA?
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RNA was the initial molecule of life
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Ribozyme
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catalytic RNA molecule
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ligase
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puts things together
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RNA molecules are self complimentary...this means?
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They coil into 3D structures
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Since RNA molecules are self complimentary, can they be templates for their own synthesis?
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Yes
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RNA molecules can for enzymes that show what?
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polymerase and ligase activities
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Polymerase adds ___ while ligases put _____together
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bases, segments
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What is the hypothesis on the evolution of the genetic code?
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1). The first codons were GNC; the first amino acids were valine
alanine, aspartate, glycine (hydrophobic, polar, charged, turnable) • most common amino acids in Miller-Urey experiments • most common amino acids in Murchison meteorites 2). 4 original codons/anticodons started coding for groups of amino acids: • GUC -- valine/isoleucine/leucine (hydrophobic) • GCC -- alanine/threonine/proline/serine (neutral polar) • GAC -- aspartate/glutamate (charged) • GGC -- glycine (flexible) 3). RNAs with the anticodons developed new abilities… • to bind the corresponding amino acids • to make the binding covalent • to drop ambiguity by evolving anticodons for the different amino acids 4). Through cycles of mutation (of the anticodons and the 3D structures) and selection, these RNAs developed binding to new amino acids. |
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After forming amino acids, what is the essential next step in the process of creating a genetic code?
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peptide bonds
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Why are most well expressed genes transcribed in the direction of replication?
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Related to leading vs lagging strands in replication
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For that weird picture with the yellow and pink genes, which is one side more colored than the other?
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The genes on either side are more intact, meaning there are no gaps, which is more efficient
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How efficient are viruses/ bacteria's genome compared to eukaryotes?
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Prokaryotes have more efficient genome than eukaryotes because eukaryotes have a lot of gaps in them
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RNA shows a combination of what characteristics essential for life?
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catalysis, heredity, evolution
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Genomes may have evolves to put essential, highly-expressed genes near the ______ and on the strand that is ______ during replication.
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origin, "leading"
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The genetic code may have arisen through a link between what...
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GXC nucleotide triplets and common amino acids (valine, alanine, aspartic acid, glycine)
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The genetic code may have arisen through a link between what...
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GXC nucleotide triplets and common amino acids (valine, alanine, aspartic acid, glycine)
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What are stromatolites?
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layered rocks formed under think microbial mats
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What were the oldest actual fossils thought to be of?
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cyanobacteria
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How old are the oldest fossils dated back to?
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3.5-3.6 billion years ago
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How can you tell fossil stromatolites from normal rock layers?
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Stromatolites layers are curved because they were formed by organisms rather than the gravity on sediment of the Earth
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Where were the stromatolites form in Bill Schopf's study?
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Apex chert in Wester Australia
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What did Martin Brasier, opposer of Schopf's claim that stromatolites had been cyanobacteria, think the fossils were?
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inorganic carbonaceous precipitates
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Methanogens produce methane by reducing what....
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carbon dioxide
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How do stromatolites grow?
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1. Bacterial slime catches fine silt at high tide
2. Photosynthesis uses up CO2 and makes it easy for carbonate to crystallize on the mats (then the bacteria go up and the process repeats) |
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Hypothesis: stromatolites 3.5 billion years ago were
produced by organisms that: |
•existed in an anaerobic environment
•produced slime •took up CO2 |
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What is the clue stromatolites are more complex than they seem.
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There may be eight different zones in a stromatolite, each
with its own microenvironment and each only a few millimeters thick. The zones vary from super-rich in oxygen...to zones without oxygen or light, saturated with H2S (hydrogen sulfide). ( |
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Some Archea reduce ____ using _____ as a reductant
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CO2, H2
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What color bacteria fix Co2 in anaerobic conditions?
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Green and purple
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What was the most important evolutionary innovation, leading to a wide range of adaptations?
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Origin of eukarya
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Plasma membrane hypothesis
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Cell formed by plasma membrane folding inwards to form everything else
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Mimivirus hypothesis
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Giant marine DNA virus formed the nucleus
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Endosymbiosis hypothesis
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! Nucleus from symbiosis of
archaean in bacterium (or vice versa) ! Mitochondria from symbiosis of alpha-proteobacterium (includes E. coli, non-sulfur purple photosynthetic bacteria, Kreb cycle?) in nucleated host ! Plastid from symbiosis of photosynthetic bacterium in nucleated host |
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What are the evidences for the endosymbiosis hypothesis?
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Structural similarities between plastids (and mitochondria)
and bacteria. Present day endosymbioses show ease of symbiosis |
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Although there are claims relating ancient stromatolytes to modern, cyanobacterial stromatolytes, the first cells lived in an ______ environment and most likely did not get energy from ___________ _____________. |
anoxic, oxygenic photosynthesis.
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The first cells ever were prokaryotic or eukaryotic? |
prokaryotic
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Endosymbiosis involving _______ and ________ produced eukaryotic cells. |
bacteria and archaea
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