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Kindle Notes & Highlights
by
Brian Greene
Read between
January 18 - January 23, 2021
Groups of three consecutive letters on a given rail of DNA denote one particular amino acid from the collection of twenty.
protein built from, say, a thousand linked amino acids would be coded by a specific sequence of three thousand letters
Such a sequence constitutes a gene, the instructional blueprint for assembling a protein.27
Every molecule of DNA, whether from seaweed or Sophocles, encodes the information needed to build proteins in the same way.
That is the unity of life’s information.
When oxygen grabs electrons, we say that it has been reduced
When carbon or hydrogen relinquishes electrons to oxygen, we say that it has been oxidized.
Oxygen, the most electron-crazed receptor of all, waits for the electron at the bottom of the stairs, and when it finally arrives, the oxygen hugs the electron tight, squeezing out the marginal energy it can still provide, thus concluding the energy extraction process.
“Life is nothing but an electron looking for a place to rest.”
electromagnetic energy is another, generated by pushes and pulls among a wealth of charged particles;
new molecular recipient experiences the twitch.
proton battery.
In a living cell we encounter an analogous situation, with pent-up protons replacing pent-up electrons.
Cellular redox reactions thus charge up biological proton-based batteries.
protons are all clustered on one side of an extremely thin membrane (just a few dozen atoms wide), the electric field (the membrane voltage divided by the membrane thickness) can be enormous, upwards of tens of millions of volts per meter.
As they turn, the molecular turbines repeatedly cram together two particular input molecules (ADP, adenosine diphosphate plus a phosphate group), synthesizing one particular output molecule (ATP, adenosine triphosphate).
It is that very energy, released by the dissociation of ATP molecules, that powers cellular functions.
The functions that keep a typical cell alive for just a single second require the energy stored in about ten million ATP molecules.
every second you consume on the order of one hundred million trillion (1020) ATP molecules.
all life emerged from a common ancestor.
reproduction yields descent with modification.
Darwinian evolution almost seems self-evident.
copying errors creep in at the rate of roughly one per every one hundred million DNA base pairs.
99 percent of the misprints are repaired by chemical proofreading mechanisms operating within each cell, reducing the net error rate to about one per every ten billion base pairs.
innovation by trial and error.
The cost of innovating by small random changes is a cost nature can bear.
Darwinian framework
essential ingredients—replication, variation, and competition—are
Like DNA, molecules of RNA thus embody cellular information and so are a component of a cell’s software.
DNA is content to be a cell’s oracle, a fount of wisdom directing cellular
RNA is willing to get its hands dirty with the manual labor of...
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ribosomes—miniature factories that snap together amino acids to yield proteins—have a particular variety of RN...
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RNA is thus both software an...
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promote the replication of ...
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RNA itself can promote the synthesis of the base pairs necessary for its own replication.
molecular Darwinism forward.
its cellular software.
Life is physics orchestrated.
entropic two-step.
Prigogine’s results provided a mathematically precise articulation of his slogan “order from chaos”;
We need to understand reality on scales far smaller than Newton considered, a path that has taken us to quantum physics,
We need to understand reality on scales far larger than Newton considered, a path that has taken us to general relativity,
we need to understand reality on scales far more complex than Newton considered,
The art of science, of which Newton was the master, lies in making judicious simplifications that render problems tractable
The challenge is that simplifications effective for one class
“Sweet is sweet, bitter is bitter, hot is hot, cold is cold, color is color; but in truth there are only atoms and the void.”
different. In modern language, atoms and molecules are not the stuff of thought. Descartes’s stance
The mind is not large enough to contain itself: but where can that part of it be which it does not contain?”
Go to your bosom, / Knock there, and ask your heart what it doth know”
Music is the hidden arithmetical exercise of a mind unconscious that it is calculating”
