Part of an ongoing serial story Niko followed silently behind Mrs. Stone, but his mind was agitated. He turned over her few words in his mind, much like a jackdaw would look for jewels among pebbles. What did she mean by saying only a fortunate few are welcomed here? Hadn’t he decided on his own … Read more #2 The Beginning part 2
I have come to a conclusion. Perhaps if I had thought about it more carefully at first I would not be surprised. But it has only recently occurred to me that a great deal of the disturbance about evolution—yes, no, theistic, atheistic, guided, unguided, young earth, old earth, Darwinist , near- neutralist, whatever! is about … Read more Not A Simple Question
Part of an ongoing serial story There once was an old woman with a magical house. Every now and again the house would grow a new room, and the old woman would know it was time to expect guests. She never knew who would come, or when, just that some day there would be someone … Read more #1 The Beginning
Why is the world a beautiful place and why does it touch me? When I was 16, my parents gave me a horse. I was a fairly typical teenager— alienated, self-absorbed, and without a way to ground my understanding of the world. I had received a certain worldview from my parents, but it was incomplete … Read more Beauty Leads Us Home
The world is a beautiful place–on balance much more beautiful than we should expect, since as a rule, natural beauty has no advantage in it. The Alps don’t gain by their beauty, neither do the Azores or the Milky Way. And we don’t gain by finding them beautiful either.
Some might argue that certain kinds of of biological beauty confer a fitness advantage, but even that is problematic. For more, see Beauty Will Lead Us Home.
In this blog, I try to capture beauty in as many ways as I can. I have posts about science, posts with original poetry, and posts with some original music, all in the hope that they will strike a chord for some.
I have never written fiction before. But I have always wanted to try. So I am going to jump out of the airplane–and see where the story takes me. The difference is, this will be a kind of performance art, because I will be improvising the story in front of you, my audience. I have three episodes so far. When I began I had no plot, no script, no mental sketch as I sat down to write. No idea where the story would go or what it would be about. No parachute. My husband says, you don’t do that unless the plane is on the ground. So maybe I have a small parachute.
I follow the same rules for each episode. I may have a vague idea of where I want to go, but there is always a turn that is unexpected, even to me.
I am having fun, but this is early days yet. I haven’t written myself into a corner or created a ridiculous contradiction or worse, grown predictable and boring.
Tune in periodically to catch up on episodes. Let me know what you think in the comments. I will list the episodes and their permalinks here so you can find them. Wish me luck!
When a city starts out with a major energy deficit, there are two changes that should be made: to be really, and I mean really efficient at recycling the critical resource, or to buy more energy.
What about in biology? Cells are like cities, right?
We already know from the previous post https://anngauger.blog/2019/11/23/is-this-any-way-to-run-a-city/ that the cell has an energy budget that is out of balance based solely on biosynthesis and use of AT.P It is in a predicament. It has an extreme shortfall in ATP in its balance sheet, needing six ATP just to make one. ATP is a high energy molecule. All that energy has to be loaded into the molecule during its synthesis by using up other ATP molecules.
If chemical A is necessary for the synthesis of more chemical A, then A has the power of replication (such systems are known as autocatalytic systems). …We find that intermediary metabolism is invariably autocatalytic for ATP.
Kun et al., Genome Biology 2008, 9:R51
The cell needs to have ATP before it can make ATP, and it has to have more ATP than it can make. Can the cell rescue its metabolic state by bringing in ATP from outside? Sure, indirectly– if it eats biological material other cells have made, it can get ATP by breaking down glucose into pyruvate, and then pyruvate into citrate, and then ultimately, the energy is harvested and and a net gain in ATP is produced. The glucose to pyruvate digestion happens in the cytoplasm, but the citrate to final energy harvest all occurs in marvellous mysterious voyagers in our cells called mitochondria.
Mitochondria are the microscopic power plants of the cell whose purpose is to take citrate and convert it to ATP,
the cell’s energy currency. Resembling miniature blimps with corrugated double membranes, they carry out an interlocking series of chemical reactions that squeeze out every last possible ATP from the breakdown of glucose. It’s a highly efficient, environmentally friendly process. Everything is recycled — one part of the process is called the citric acid cycle because it regenerates itself with each new round. In fact, everything cycles.
Most cells have many mitochondria, whose characteristic wrinkled stroma serve to increase the interior membrane surface area. Think of a bag with a much bigger bag neatly tucked in folds inside. Embedded in that folded inner membrane are all machinery of energy production that makes life possible. And that machinery is considerable. An ensemble of multiple proteins come together to make 5 protein complexes, shown in the picture below. In complexes 1-4, energy in the form of electrons is received by them and cycled through and, then using some of that energy to pump protons across the membrane. As citrate is gradually broken down, compounds like NADH or succinate are produced, and shunted off to the electron transport chain, and they also contribute to the process.
Even the last high-energy electrons from the breakdown process are not wasted: a chain of proteins in the inner membrane passes these electrons like little hot potatoes from one to another, using the energy of each transfer to pump hydrogen ions across the membrane, so that a molecular machine called ATP synthase can take advantage of the hydrogen gradient to create even more ATP.
In the drawing you can see the direction of H+ flow out and then in again, and how many different proteins make up each protein complex. There are 5 complexes, whether in an animal, or a plant.
The fifth complex is ATP synthase. This is where the miracle happens that makes life possible. ATP synthase harvests the energy of the proton gradient to recycle ADP to ATP. Like a turbine in a hydroelectric plant, ATP synthase lets the hydrogen ions flow back across the membrane through itself, rotating as the ions pass through, and As it rotates it adds a phosphate to ADP at each crank, thus restoring ATP to use.
We naturally think of death as something awful, a scourge to be dreaded and put off for as long as possible. But biological death has its positive side. Think of self-sacrifice—death for the good of others. That kind of death we think of as altruistic, even noble, attributing it to heroes or saints. And most of us don’t realize that such self-sacrifice is written into our bodies, at the deepest levels of our being.
The process is called apoptosis, in which cells kill themselves from within. It is not death due to overwhelming damage—that’s another process and called by another name. Rather it is a programmed process whereby cells self-destruct. They shred their DNA, internal organelles (specialized parts of cells) condense, and membranes bleb (blister). Then scavenger cells come by and clean up the remnants for recycling.