CAUTION: ENZYMES AT WORK: PART I: CELLULAR ENERGY
We live in a world made from matter. Matter is made up of atoms and molecules that follow the laws of nature. All life is made up of atoms and molecules that are organized into cells. Our body has trillions of them. Since our cells are made from matter they too must follow the laws of nature as well. These laws demand that to produce, move or control anything requires a certain amount of energy. So, just like a light bulb without electricity or a car without gas, our body is as good as dead if it doesn't have enough energy to do what it needs to do to survive within the laws of nature.
Everybody knows that we have to breathe in air and eat food to stay alive. And most people know that it is mainly the molecular oxygen in the air we breathe and the sugar in the things we eat and drink that gives us the energy to live. There are even some people who know that it is the mitochondria inside our cells that do the work of releasing the chemical energy stored inside the glucose molecule to get the energy we need. But what most people do not understand or appreciate is how the cells in the body actually accomplish this task. This is the reason why almost everybody does not seem to know that when not resisted by some sort of innovation the laws of nature do not bring about life, as evolutionary biologists would have us believe, but death. The body's use of glucose and molecular oxygen to get enough energy to survive is a good example of this truth. So how does the body do it? One of the most important sets of molecules in the body are enzymes. Let's first look at what enzymes are and what they do and then we'll be able to better understand how they help the body get the energy it needs to survive within the laws of nature.
Enzymes are special molecules (mostly proteins) that are made in the cell which help other molecules undergo chemical reactions when they come in contact with each other. When these reactions occur energy is either released or used up and different molecules are produced. Every biochemical process in the body requires enzymes to work properly.
Molecules are made up of atoms joined together by chemical bonds. There are very small molecules, like molecular oxygen (O2), which is made up of two oxygen atoms joined together and water (H2O) which is made up of two hydrogen atoms joined to one oxygen atom. There are also slightly larger molecules, like glucose (C6H12O6), a sugar that is made up of six atoms of carbon and oxygen joined to twelve atoms of hydrogen. And there are very large molecules, like carbohydrates, fats, and proteins, many of which are made up of hundreds or even thousands of atoms joined together.
When molecules meet up with each other they sometimes react. A reaction between molecules simply means that chemical bonds between atoms are created or destroyed. This usually causes some of the atoms in the reacting molecules to change places with each other to form different molecules. Some enzymes help chemical bonds be destroyed in larger molecules to form smaller ones. And other enzymes help chemical bonds be created between smaller molecules to make larger ones. During this process energy may be released or used up. At the end of the reaction the enzymes are not altered so they can continue to promote more reactions. Also, the total number of atoms present in the molecules that are produced at the end of the reaction is the same as there were in the molecules that reacted in the first place. In other words, in a chemical reaction no new atoms are created or destroyed, just the bonds between them, and this often results in the release or use of energy and the atoms involved changing partners to form different molecules.
The laws of nature determine how fast specific molecules will react with each other. But the addition of an enzyme makes this reaction take place much faster. By speeding things up enzymes help to produce many more new molecules, usually in the order of thousands or millions of times more, than what would naturally happen within the same time frame. This is why enzymes are called catalysts. They help bring molecules together to react much faster than what would normally happen within the laws of nature alone. In fact, if our body were left to only the natural laws of chemistry, the thousands of reactions we need to help keep us alive would not take place fast enough and we would die.
There are thousands of different enzymes in the body each of which have a specific effect on a specific molecule. It is the specific shape and chemical nature of the enzyme that determines which specific molecules it works on and what specific type of reaction it catalyzes. This is similar to how hormones have a specific effect on specific cells by locking on to specific receptors on their surface (see prior articles entitled Caution: Hormones At Work). The first part of the chemical name of an enzyme usually indicates the specific molecule or class of molecules for which it speeds up reactions. And the last part of its name usually ends in ase . For example, lactase is the enzyme that helps to breakdown lactose the sugar in milk. And a protease is a class of enzymes that helps to breakdown proteins which are made up of two or more amino acids bonded together.
The body often uses several specific enzymes in a specific order or pathway, like in a chain reaction, to bring about what is needed for survival. The first molecule undergoes a reaction catalyzed by the first enzyme, and one of the products of that reaction becomes the second molecule in the pathway. The second molecule, in turn, undergoes a reaction catalyzed by the second enzyme, and one of the products of that reaction becomes the third molecule in the pathway. The third molecule, in turn, undergoes a reaction catalyzed by the third enzyme, and one of the products becomes the fourth molecule in the pathway, and so on. This process continues until the required molecule is produced so it can do what the body needs it to do. If any one of the enzymes in the pathway were to be missing or not working properly then not enough of the final product would be produced and life could hang in the balance.
Finally, it is important to understand that since enzymes, themselves, are made up of hundreds or thousands of atoms chemically bonded together, their chemical stability and capacity to work properly can be affected by the laws of nature as well. Things like temperature and hydrogen ion concentration can affect the chemical structure of enzymes. When any of these parameters fall out of the normal range the enzymes in our body start to malfunction and so does our body. Serious deviations can even result in death. That is why our body must be able to control these and other vital parameters to allow us to survive within the laws of nature. (See prior articles: Caution: Hormones At Work).
For a video animation explaining enzymes see: How Enzymes Work
Now that we know what enzymes are and what they do let's see how our enzymes work within our cells to release the energy stored in glucose so we can survive within the laws of nature.
Each minute the body is at complete rest it needs the energy from about 20 mg of glucose and 250 milliliters of oxygen to keep itself alive. This energy is used to maintain the integrity and basic function of each of its trillions of cells in addition to providing adequate brain, lung, heart, liver and kidney function as well. Of course, when the body is more active it needs more energy and uses up more glucose and oxygen, mainly for skeletal and heart muscle activity. Since the brain is constantly working hard to keep the body alive, when the supply of glucose or oxygen drops below certain levels it is the first organ to malfunction. This happens because the body can't provide its brain cells with enough energy for them to work properly. This results in weakness and confusion and if not corrected quickly can lead to coma and even death. The brain cells, like all the other cells in the body, use cellular respiration to get the energy they need to be able to survive and work within the laws of nature. Let's see what that involves.
Cellular respiration is the process in the cell by which the chemical energy within the glucose molecule is released by breaking the bonds between its atoms. In contrast to a car engine, which uses a spark and molecular oxygen to quickly release the energy within gasoline to produce a small explosion, cellular respiration uses molecular oxygen and a series of enzymes to release the energy from within the glucose molecule in a much more controlled fashion. However, just like for gasoline in a car engine, only a certain amount of the energy present in glucose is used by the cell and the rest is released as heat. During this chemical reaction one glucose molecule (C6H12O6) reacts with six oxygen molecules (6 O2) to release the energy the cell needs while at the same time producing six carbon dioxide molecules (6 CO2) and six water molecules (6 H2O). Notice that the reaction starts with six carbon atoms, twelve hydrogen atoms and eighteen oxygen atoms (from one molecule of glucose (C6H12O6) and six molecules of oxygen gas (6 O2). And it ends up with the same total amount of carbon, hydrogen and oxygen atoms, but now they make up six molecules of carbon dioxide gas (6 CO2) and six molecules of water (6 H2O) instead.
The first part of cellular respiration is called glycolysis. Glycolysis takes place inside the cellular fluid (cytosol). This process does not use molecular oxygen and is therefore anaerobic. Glycolysis uses ten specific enzymes in a chain reaction to help break down glucose, which contains six carbons (C6H12O6), into two molecules of pyruvate each of which contains three carbons (C3H6O3). Along the way a small amount of energy is released that can be used by the body. Pyruvate then moves into the mitochondria where the second (citric acid cycle) and third (electron transport chain) parts of cellular respiration take place. Both of these two processes require molecular oxygen and are therefore aerobic.
In the mitochondria, pyruvate enters the citric acid (Krebs) cycle which uses eight specific enzymes and molecular oxygen in a chain reaction to break it down into carbon dioxide (CO2). The hydrogen released is picked up by carrier molecules. In the mitochondria these hydrogen carrying molecules enter the electron transport chain which uses a series of proteins and molecular oxygen to form water (H2O). Along the way more energy is released that can be used by the body. The addition of molecular oxygen in aerobic metabolism yields about fifteen times more energy than what comes from anaerobic metabolism (glycolysis) alone.
Experience teaches that the body's need for molecular oxygen is so acute that without it we can only live about four minutes. This means that our body needs the large amounts of energy released from glucose in the presence of molecular oxygen to survive. In other words, we must have enough molecular oxygen to drive the citric acid cycle and the electron transport chain in the mitochondria of our cells, because the small amount of energy provided by anaerobic glycolysis alone is not enough to keep us living for very long. There are five important points to remember about cellular respiration.
First, if you put glucose in coffee or tea it could sit there for an eternity and it would never turn into two molecules of pyruvate by the laws of nature alone. Glycolysis can't take place without the ten specific enzymes needed to facilitate each of the ten different chemical reactions needed to convert one molecule of glucose (C6H12O6) into two molecules of pyruvate (C3H6O3) while releasing some energy.
Second, bubbling molecular oxygen into a solution containing pyruvate would never, on its own, naturally bring about carbon dioxide and water. The citric acid cycle and the electron transport chain, present in the mitochondria, cannot work properly without the eight specific enzymes and the series of proteins they need to release the required amount of energy from the glucose molecule.
Third, each of the twenty or more enzymes and carrier molecules involved in cellular respiration is made up of about three hundred or more amino acids lined up in a specific order which gives each of them the ability to perform their function. Since there are twenty different amino acids that can be used by the cell to produce a given protein, the chances of any one of these molecules coming into being at random is at least 20300 which is equal to one chance in 10390. For those who believe that given enough time anything can happen, it is sobering to realize that since there are 86,400 seconds in a day (60 x 60 x 24) and 31,557,600 seconds in a year (x 365.25), this means that the earth has existed for only 1.4 x 1017 seconds (x 4.5 billion). Moreover, if one assumes, hypothetically, that in every nanosecond (10-9 sec) of the Earth's existence a trillion trillion trillion (1036) chemical reactions producing a protein with about 300 amino acids could have taken place then there would have only been 1.4 x 1062 of these reactions in the lifetime of the earth. But, a total of 10390 of these chemical reactions would have been needed to get just one of these molecules anyway. It would seem that, in at least this hypothetical scenario, for just one of these molecules to come into being one would have to wait until the earth was older by a factor of 10328. Moreover, the chances of twenty of these specific proteins coming together in a specific pathway to achieve what is needed would be in the order of 10390 x 20 (107800). Clearly, this is an impossibility and is why our cells, rather than relying on random chance and the laws of nature alone, use the instructions contained within the DNA in their nuclei to produce enough of these types of molecules to keep us alive. But how much is enough and how the production of these molecules in each cell is controlled is as yet unknown.
Fourth, the specific enzymes and series of proteins work in a specific order (pathway), like in a chain reaction, to bring about the energy the body needs from cellular respiration. If any one part is missing or not working properly then the whole system can malfunction and result in death. For example, the poison, cyanide, blocks the function of just one of the enzymes in the electron transport chain. And arsenic blocks one of the enzymes in the citric acid cycle. Ingesting enough of either of these poisons can quickly lead to death. This happens because although there is enough glucose and molecular oxygen in the body its cells can't get the energy they need to stay alive because each of these poisons has blocked just one component of the cellular respiration pathway.
Finally, the energy released from the glucose molecule by cellular respiration is not in an immediately useable form. In a car, the semi-explosive release of energy from the combustion of gasoline in the presence of molecular oxygen in its engine is immediately used to power it down the road. This takes place by way of the actions of the pistons through the transmission and the drive train. However, the cell takes the energy it gets from the breakdown of glucose and stores it, like a battery, in certain molecules.
The most common energy-storage molecule in the cell is ATP (adenosine triphosphate). It is known as the energy currency of the cell and has three high energy phosphate bonds. An enzyme called ATP synthase takes the energy from cellular respiration and uses it to produce ATP. The cell then has other enzymes, connected to micro-machines, that take the energy from ATP (like a battery powering an appliance) and use it for the work they need to do to keep the cell functioning properly. These activities include the production of DNA, RNA and all of the proteins in the cell, muscle contraction, the transport of proteins inside the cell, and the importing and exporting of various atoms and molecules across the cell membrane. Every moment of every day our cells are releasing the energy from glucose and storing it in ATP while at the same time releasing the energy stored in ATP so they can do what they need to do to stay alive.
For video animations explaining what is discussed above please see the following:
How Glycolysis Works
How the Krebs Cycle Works
Electron Transport System and ATP Synthesis
Points to Ponder
It was the extremely high improbability of any one of the thousands of biologically significant molecules, like the twenty or more enzymes and carrier molecules involved in cellular respiration, being formed by just chance and the laws of nature (never mind the need for the untold millions of each one of them to allow for life) that alerted scientists to there having to be an intelligent agent within the cells telling them how to make them. This is what first motivated scientists to search for and find the DNA molecule and everything else connected to it that has been, and continues to be, discovered. But, paradoxically, modern evolutionary biologists see all of the information packed into the DNA molecule and still conclude that it all came about by just chance and the laws of nature alone rather than a mind at work(i.e. an intelligence). In other words, scientists, using their ability to detect intelligence, recognized that there had to be an intelligent agent inside the cell instructing it on how and when to produce these complex and vital molecules. But after finding it they concluded that this intelligent agent itself had come about by chance and the laws of nature alone. Alternatively, many people now believe and teach that it was nature itself, as the intelligent agent, that through evolution, brought about DNA and all of the innovations needed for life because that was what was needed. They seem to forget that, by definition, evolution, as described by evolutionary biologists, is a blind process which has no goals.
The body’s ability to get the energy it needs to live from the breakdown of glucose in the presence of molecular oxygen is dependent on over twenty different enzymes and carrier proteins arranged in a specific order. Each one of these proteins, which contribute to cellular respiration, is made up of three hundred or more amino acids in a specific order that work together in a specific pathway to get the job done. Clinical experience teaches that the absence or malfunction of any one of these components results in death as shown above by the examples of cyanide and arsenic. Dr. Michael Behe has called a system where the absence of any one part renders it useless as being irreducibly complex. It certainly looks like the numerous enzymes and carrier proteins needed for cellular respiration demonstrates irreducible complexity.
However, just having an irreducibly complex system does not automatically allow for survival. In the case of cellular respiration, to get enough energy to stay alive, not only does there have to be enough of each of the enzymes and carrier proteins present but they must also work in the right order and be effective enough as well. A chain is only as strong as its weakest link and a machine is only as efficient as its slowest part. So too, the body’s ability to get the energy it needs to work properly, whether at complete rest or at high levels of activity, is dependent on, not only the mere presence of the various enzymes and transport proteins of cellular respiration, but also the amount and efficiency of each of them as well. Besides being irreducibly complex, systems that allow for life must also have a natural survival capacity. By this I mean that each system must give the organism the capacity to survive by taking into account the laws of nature. This usually involves having a knowledge of what is needed to keep the organism alive within the laws of nature and then being able to do what needs to be done. Cellular respiration, which uses specific molecules in a specific order to allow the body to get the energy it needs to survive, seems to know what is needed to get the job done and does it naturally.
To hear evolutionary biologists tell it, all you have to do is show how each of the enzymes and carrier proteins involved in cellular respiration may have come about from some natural process, such as gene duplication, and that in and of itself should be sufficient to confirm that the cellular respiration came about solely by chance and the laws of nature alone. But this is a preposterous notion. It’s like trying to explain how the engine that is able to power a go kart eventually developed into one that can power a dump truck without taking into account everything else that’s different between them. For these innovations, like cellular respiration being able to obtain enough energy from the glucose molecule, did not develop within a vacuum and therefore should not be considered in isolation from what must have been going on within these intermediate organisms for them to survive in the first place. To do so seems to be a tad simplistic and frankly, unscientific. Moreover, nowhere is it discussed by evolutionary biologists how incredibly lucky it was that each of the enzymes and carrier proteins needed in the pathway just happened to come together in the right order to do the job. Nor how fortunate it was that the final result of cellular respiration was to provide the human body with enough of the energy it needs to survive in the world.
Given what we know about how life actually works and how easily it dies when it doesn't have enough energy, it is evident that for cellular respiration to have developed naturally within living organisms that could reproduce, would have required several simultaneous innovations. What those innovations were and exactly how those intermediate organisms were able to get enough energy to live in these intermediate phases may never be known. This is because further changes which may have come about have since gone by the wayside of historical science and evolution and we can only see what is present now. This is one way to explain how cellular respiration may have evolved without having to seriously consider the physiology of the now extinct intermediate organisms. But this is not Science, where every aspect of the reverse engineering needed to come up with a plausible explanation should be explored before a theory is proclaimed to the public. No, this is faux science and just wishful thinking. It’s also how evolutionary biologists have been able convince themselves, and others, of the supposed irrelevance or even impossibility of irreducible complexity. Some scientists have argued that the positions of intelligent design and irreducible complexity are arguments from ignorance which lack enough imagination. I would submit that the concerns put forth above are based, not on ignorance, but on what we actually do know about how life actually works and how easily it dies. But I wholeheartedly agree that, based on the current evolutionary theory of how cellular respiration came into being, with no consideration of any of the factors mentioned above, that evolutionary scientists do indeed have very good imaginations. Alas, we who believe that the design seen in nature is real, and not an illusion, are forced to limit our imaginings to what is already known about what it takes for life to survive within the laws of nature.
The laws of nature have put up many obstacles to prevent life from existing. Just as a car can die from not having enough gas for energy, or oil for seizing parts, or anti-freeze for engine overheating, so too, all physicians know that there are many different pathways to death. If you really want to begin to understand how life came into existence, you first have to understand how easily it can become non-existent. Did life really come about solely by random chemicals coming together to form cells, then simple organisms, and then complex ones like us? In other words, without a mind at work to make it happen? Do you think that the over twenty different enzymes and carrier proteins, each consisting of over 300 amino acids, just happened to come together in a specific pathway, called cellular respiration, to provide our cells with the energy they need to live? No, when it comes to the origin of life it seems to me that Science still has a lot of explaining to do. Meanwhile, as we wait for evolutionary biologists to admit the deficiencies within their theory, our children and the whole world continue to be misled!
Be sure to catch all of the articles in Dr. Glicksman's series, "Beyond Irreducible Complexity."
Howard Glicksman M. D. graduated from the University of Toronto in 1978. He practiced primary care medicine for almost 25 yrs in Oakville, Ontario and Spring Hill, Florida. He now practices palliative medicine for a Hospice organization in his community. He has a special interest in how the ethos of our culture has been influenced by modern science’s understanding and promotion of what it means to be a human being.
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