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20 Cards in this Set
- Front
- Back
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What are the 2 necessary and defining characteistics for life as it pertains to the origins of life?
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1. The ability to reproduce (self-replication)
2. The ability to acquire molecules and use them in a controlled chemical reactions that maintain conditions suitable for life and that contribute growth (metabolism) |
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How are reactions controlled today?
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Reactions are controlled because enzymes and reactancts are bound to the plasma membrane of a cell.
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Organism
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Cellular-based life.
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Nucleic Acid
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A polymer made up of nucleic monomers.
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Nucleotide
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Monomer composed of
1. a sugar (ribose/deoxyribose) 2. a phosphate group 3. a nitrogenous base (A,T,U,G,C) |
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How does the composition of nucleotides seem to contridict the theory that the origin of life was RNA?
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Ribose is not particularly plentiful in experimental chemical evolution (the Ribose problem); also --> the origin of pyrimidines is unsolved as of yet.
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What is the primary structure of DNA?
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The sequence of nucleotides.
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How is the sequence of DNA written, and why is it written this way?
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DNA is written from the 5' end to the 3' end (5' and 3' refer to the carbons in the sugar ring) because that is the way it is metabolized in cells.
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T/F Polyermization is endergonic.
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True. Polymerization is endergonic. The free energy of the 2 phosphate groups added to the nucleotides, creating nucleotide triphosphates, allows it to take place.
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Explain the process of gel electrophoresis
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Proteins and nucleic acids carry a charge; negatively charged particles move toward positive electrode and positive toward negative; Molecules are separated by size and charge (larger are slower, higher charge are faster); the segments are either dyed or radioactively marked (autoradiography).
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Name the 3 givens Watson and Crick had to work with.
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1. DNA had a regular and repeating structure
2. # pyridines = # purines 3. DNA had a sugar/phosphate bckbone |
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What did Watson and Crick discover about the structure of DNA?
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*DNA strands run antiparallel with interior bases, paired complimentarily (A & T, C & G); it is negatively charged and water soluable; with 2 nm width, 10 bases rungs per turn, 3.4 nm per turn
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Why couldn't DNA have been the first form of life?
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Its regular and repeating structure make it a horrible catalyst; it fails condition 2.
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T/F The ribose in RNA is less reactive than the deoxyribose in DNA.
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False. Ribose is much more reactive due to its extra hydroxyl group on the 2' Carbon. It can take place in reactions that tear the molecule apart
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What are the 2 functions of RNA?
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1. Catalyst (like proteins)
2. Informaiton carrier (like DNA) |
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Explain the experiment to create self-replicating RNA.
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The experimenters mimicked natural selection and mutations to create different variations of RNA; by round 18, RNA could catalyze; almost test tube life.
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What is a ribozyme and why is it important to the theory of chemical evolution?
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Ribozymes (like RNA replicase) can synthesize the replication of RNA; this is a key aspect of creating a copy (creating a template).
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Template Strand
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The original strand of DNA
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Describe the hairpin structure of RNA.
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RNA is one-stranded, but it folds back upon itself spontaneously, running antiparallel and stabilized by hydrogen bonds.
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Complimentary Strand
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The new strand of RNA; it is independant of the old strand and has opposite bases- its complimentary strand would be the same as the first template strand.
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