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Glycolysis and Alcoholic Fermentation

Glycolysis (from glycose, an older term for glucose + -lysis degradation) is the metabolic pathway that converts glucose C6H12O6, into pyruvate, CH3COCOO− + H+. The free energy released in this process is used to form the high-energy compounds ATP (adenosine triphosphate) and NADH (reduced nicotinamide adenine dinucleotide).Yeast cells obtain energy under anaerobic conditions using a very similar process called alcoholic fermentation,  also referred to as ethanol fermentation, is a biological process in which sugars such as glucose, fructose, and sucrose are converted into cellular energy and thereby produce ethanol and carbon dioxide as metabolic waste products.

Glycolysis requires 11 enzymes which degrade glucose to lactic acid (Fig. 2). Alcoholic fermentation follows the same enzymatic pathway for the first 10 steps. The last enzyme of glycolysis, lactate dehydrogenase, is replaced by two enzymes in alcoholic fermentation. These two enzymes, pyruvate decarboxylase and alcoholic dehydrogenase, convert pyruvic acid into carbon dioxide and ethanol in alcoholic fermentation.

The most commonly accepted evolutionary scenario states that organisms first arose in an atmosphere lacking oxygen.1,2 Anaerobic fermentation is supposed to have evolved first and is considered the most ancient pathway for obtaining energy. However, there are several scientific odds against that.

First of all, it takes ATP energy to start the process that will only later generate a net gain in ATP. Two ATPs are put into the glycolytic pathway for priming the reactions, the expenditure of energy by conversion of ATP to ADP being required in the first and third steps of the pathway (Fig. 2). A total of four ATPs are obtained only later in the sequence, making a net gain of two ATPs for each molecule of glucose degraded. The net gain of two ATPs is not realized until the tenth enzyme in the series catalyzes phosphoenolpyruvate to ATP and pyruvic acid (pyruvate). This means that neither glycolysis nor alcoholic fermentation realizes any gain in energy (ATP) until the tenth enzymatic breakdown.

Enzymes are proteins consisting of amino acids united in polypeptide chains. Their complexity may be illustrated by the enzyme glyceraldehyde 3-phosphate dehydrogenase, which is the enzyme that catalyzes the oxidation of phosphoglyceraldehyde in glycolysis and alcoholic fermentation. Glyceraldehyde phosphate dehydrogenase consists of four identical chains, each having 330 amino acid residues. The possible number of different combinations of these amino acid chains is infinite.

 

Glyceraldehyde-3-phosphate dehydrogenase

 

To illustrate, let us consider a simple protein containing only 100 aim acids. There are 20 different kinds of L-amino acids in proteins, and each can be used repeatedly in chains of 100. Therefore, they could be arranged in 20^100 or 10^130 different ways. Even if a hundred million billion of these (10^17) combinations could function for a given purpose, there is only one chance in 10^113 of getting one of these required amino acid sequences in a small protein consisting of 100 amino acids. By comparison, Sir Arthur Eddington has estimated there are no more than 10^80 (or 3,145 x 10^79) particles in the universe! Consider the 10 enzymes of the glycolytic pathway. If each of these were a small protein having 100 amino acid residues with some flexibility and a probability of 1 in 10^113 or 10^-113, the probability for arranging the amino acids for the 10 enzymes would be: P = 10^-1,130 or 1 in 10^1,130, and this result is only the odds against producing the 10 glycoytic enzymes by chance. It is estimated that the human body contains 25,000 enzymes. If each of these were only a small enzyme consisting of 100 amino acids with a probability of 1 in 10^-113, the probability of getting all 25,000 would be (10^-113)^25,000, which is 1 chance in 10^2,825,000…

Figure 2

 

 

There are still other problems with that theory. There are numerous complex regulatory mechanisms which control these chemical pathways. For example, phosphofructokinase is a regulatory enzyme which limits the rate of glycolysis. Glycogen phosphorylase is also a regulatory enzyme; it converts glycogen to glucose-1-phosphate and thus makes glycogen available for glycolytic breakdown. In complex organisms there are several hormones such as somatotropin, insulin, glucagon, glucocorticoids, adrenaline thyroxin and a host of others which control utilization of glucose.

In addition, complex cofactors are absolutely essential for glycolysis. One of the two key ATP energy harvesting steps in glycolysis requires a dehydrogenase enzyme acting in concert with the “hydrogen shuttle” redox reactant, nicotinamide adenine dinucleotide (NAD+). To keep the reaction sequence going, the reduced cofactor (NADH + H +) must be continuously regenerated by steps later in the sequence (Fig. 2), which requires one enzyme in glycolysis (lactic dehydrogenase) and another (alcohol dehydrogenase) in alcoholic fermentation.

Further, at one point, an intermediate in the glycolytic pathway is “stuck” with a phosphate group (needed to make ATP) in the low energy third carbon position. A remarkable enzyme, a “mutase” (Step 8), shifts the phosphate group to the second carbon position—but only in the presence of pre-existent primer amounts of an extraordinary molecule, 2,3-diphosphoglyceric acid. Actually, the shift of the phosphate from the third to the second position using the “mutase” and these “primer” molecules accomplishes nothing notable directly, but it “sets up” the ATP energy-harvesting reaction which occurs two steps later!

 

by Jean Sloat Morton, Ph.D.

 

References

1 A.I. Oparin, Origin of Life, New York: Dover Pub., lnc., 1965, pp. 225-26.
2 (Jark and Synge (eds.), The Origin of Life on the Earth, New York: Pergamon Press, 1959, p. 52.
3 Ernil Borel, Probabilities and Life, New York: Dover Pub., Inc., 1962, p. 28.

 

Cite this article: Morton, J. S. 1980. Glycolysis and Alcoholic Fermentation. Acts & Facts. 9 (12).

From: http://www.icr.org/article/glycolysis-alcoholic-fermentation/

 

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ATP-synthase: wonderful molecular machine

Today, we’re going to talk about an absolutely wonderful biological machine, called ATP-synthase, another marvel built on almost every living beings that fascinates and intrigues naturalistic minds! Again, to conceive that such a intricate system could have arisen after random mutations defies logic.  But, unfortunately, nothing prevents evolutionists to contrive the most bizarre hypothesis with the purpose of giving the credits to chance, nothingness again.

ATP Synthase is a molecular machine found in every living organisms. It serves as a miniature power-generator, producing an energy-carrying molecule, adenosine triphosphate, or ATP. The ATP synthase machine has many parts we recognize from human-designed technology, including a rotor, a stator, a camshaft or driveshaft, and other basic components of a rotary engine. This machine is just the final step in a long and complex metabolic pathway involving numerous enzymes and other molecules—all so the cell can produce ATP to power biochemical reactions, and provide energy for other molecular machines in the cell. Each of the human body’s 14 trillion cells performs this reaction about a million times per minute. Over half a body weight of ATP is made and consumed every day!

ATP-driven protein machines power almost everything that goes on inside living cells, including manufacturing DNA, RNA, and proteins, clean-up of debris, and transporting chemicals into, out of, and within cells. Other fuel sources will not power these cellular protein machines for the same reasons that oil, wind, or sunlight will not power a gasoline engine.

ATP synthase occurs on the inner membranes of bacterial cells, and the innermost membranes of both mitochondria and chloroplasts, which are membrane-bound structures inside animal and plant cells.

ATP synthase manufactures ATP from two smaller chemicals, ADP and phosphate. ATP synthase is so small that it is able to manipulate these tiny molecules, one at a time. ATP synthase must convert some other form of energy into new ATPs. This energy is in the form of a hydrogen ion (H+) gradient, which is generated by a different whole protein system to ATP synthase. Hydrogen ions pour through ATP synthase like wind through a windmill. This comprises a positively charged electric current, in contrast to our electric motors, which use a negative current of electrons.

ATP synthase is a complex engine and pictures are necessary to describe it. Scientists use clever techniques to resolve the exact locations of each of many thousands of atoms that comprise large molecules like ATP synthase. This protein complex contains at least 29 separately manufactured subunits that fit together into two main portions: the head and the base. The base is anchored to a flat membrane like a button on a shirt (except that buttons are fixed in one place, whereas ATP synthase can migrate anywhere on the plane of its membrane). The head of ATP synthase forms a tube. It comprises six units, in three pairs. These form three sets of docking stations, each one of which will hold an ADP and a phosphate. ATP synthase includes a stator (stationary part), which arcs around the outside of the structure to help anchor the head to the base.

 F1-ATPase

F1-ATPase

Notice in figure 1 a helical axle labeled “γ” in the middle of the ATP synthase. This axle runs through the center of both the head and base of ATP synthase like a pencil inside a cardboard toilet paper tube.

Here is the “magic”: When a stream of tiny hydrogen ions (protons) flows through the base and out the side of ATP synthase, passing across the membrane, they force the axle and base to spin. The stiff central axle pushes against the inside walls of the six head proteins, which become slightly deformed and reformed alternately. Each of your trillions of cells has many thousands of these machines spinning at over 9,000 rpm!

The spinning axle causes squeezing motions of the head so as to align an ADP next to a phosphate, forming ATP … in bucket loads. Many other cellular protein machines use ATP, breaking it down to ADP and phosphate again. This is then recycled back into ATP by ATP synthase. Lubert Stryer, author of Biochemistry adds,

“… the enzyme appears to operate near 100% efficiency …”1

Two Canadian researchers therefore looked into the innermost workings of ATP synthase. Using electron cryomicroscopy, they produced the first-ever three-dimensional representation of all the enzyme’s parts fitted together the way they are in the actual enzyme.1 Their study results, published in the journal Nature, enabled them to reconstruct the specific sequence of timed events that makes the enzyme work. And it’s a good thing that it functions, because every living cell—from bacteria to brain cells—depends on one or another version of ATP synthase.2

The team found two half-channels situated in the base of the motor, forming something like two half-stroke cylinders. The first half-channel directs a single proton to a precise spot on one of the rotor’s 12 segments where a negatively charged oxygen atom receives and temporarily holds it. After spinning 330 degrees on the rotor, the proton re-enters the cylinder assembly through the second half-channel, and is finally released into an area of lower proton concentration. (ICR)

The  F1-ATPase motor

In a paper published in March 1997, Hiroyuki Noji et al. directly observed the rotation of the enzyme F1-ATPase, a subunit of a larger enzyme, ATP synthase. This had been suggested as the mechanism for the enzyme’s operation by Paul Boyer.6 Structural determination by X-ray diffraction by a team led by John Walker had supported this theory. A few months after Noji et al published their work, it was announced that Boyer and Walker had won a half share of the 1997 Nobel Prize for Chemistry for their discovery.

The F1-ATPase motor has nine components—five different proteins with the stoichiometry of 3a:3b:1g:1d:1e. In bovine mitochondria, they contain 510, 482, 272, 146 and 50 amino acids respectively, so Mr = 371,000. F1-ATPase is a flattened sphere about 10 nm across by 8 nm high—so tiny that 1017 would fill the volume of a pinhead. This has been shown to spin ‘like a motor’ to produce ATP, a chemical which is the ‘energy currency’ of life. This motor produces an immense torque (turning force) for its size—in the experiment, it rotated a strand of another protein, actin, 100 times its own length. Also, when driving a heavy load, it probably changes to a lower gear, as any well-designed motor should.

ATP synthase also contains the membrane-embedded FO subunit functioning as a proton (hydrogen ion) channel. Protons flowing through FO provide the driving force of the F1-ATPase motor. They turn a wheel-like structure as water turns a water wheel, but researchers are still trying to determine precisely how. This rotation changes the conformation of the three active sites on the enzyme. Then each in turn can attach ADP and inorganic phosphate to form ATP. Unlike most enzymes, where energy is needed to link the building blocks, ATP synthase uses energy to link them to the enzyme, and throw off the newly formed ATP molecules. Separating the ATP from the enzyme needs much energy. (CMI)

Evolutionists’ reverie

Evolutionary scientists have suggested that the head portion of ATP synthase evolved from a class of proteins used to unwind DNA during DNA replication, i.e, the hexameric helicase enzyme. 3

However, how could ATP synthase “evolve” from something that needs ATP, manufactured by ATP synthase, to function? Absurd “chicken-egg” paradox! Also, consider that ATP synthase is made by processes that all need ATP—such as the unwinding of the DNA helix with helicase to allow transcription and then translation of the coded information into the proteins that make up ATP synthase. And manufacture of the 100 enzymes/machines needed to achieve this needs ATP! And making the membranes in which ATP synthase sits needs ATP, but without the membranes it would not work. This is a really vicious circle for evolutionists to explain.

Some says that not every living beings need ATP-synthase, such as anaerobical bacteria, because they produce ATP via glycolysis only. Thus, they imply that evolution really occurred on the creation of ATP-synthase… But every organism need ATPase!

Obligate anaerobes may not use ATP synthase to manufacture ATP, but they do use it to pump protons out of their cytoplasm. They would die otherwise. All cells have ATP synthase, because all cells need it. In sum, all life depends on ATPase, but not all life depends on it for ATP production. Anaerobic bacteria use it to maintain pH balance instead. So ATPase must have been present in the very first cell.

As the researches advance, more impressive facts are disclosed! The necessity of engineering  ATPase is actually just the tip of the iceberg. One amazingly revealing 2010 study in the journal Nature demonstrated how not only ATPase, but the entire electron transport chain apparatus and in fact whole mitochondria were absolutely essential to the ‘first’ eukaryote. 4

So, the evolutionary dilemma only strengthens! Oh, surely they miss the Darwin’s epoch, when cells were just organic “jellybeans”, which no complex content, the eye anatomy was the most complicated biological mechanism they’ve had to deal with (and even the contemporary knowledge of eye was enough to puzzle Darwin’s mind!), there was no annoying DNA (with its smart informational content pointing to a intelligent Creator), second Laws of Thermodynamics denying spontaneous increasing in complexity of polymers occurring naturally, and so on… Damn it, science, always disturbing godless people dreams!

References

______________________________________________

1 Stryer. L., Biochemistry, 18.4.3., The world’s smallest molecular motor: rotational catalysis, online: <www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=stryer.section.2528# 2539>.

2 Lau, W. C. Y. and J. L. Rubinstein. 2012. Subnanometre-resolution structure of the intact Thermus thermophilus H+-driven ATP synthase. Nature. 481 (7380): 214-218.

3 Evolution of the F1-ATPase <www.life.uiuc.edu/crofts/bioph354/Evol_F1.html>.

4 Lane, N. and W. Martin. 2010. The energetics of genome complexity. Nature. 467 (7318): 929-934.

Also:

http://creation.com/atp-synthase-in-all-life

http://creation.com/design-in-living-organisms-motors-atp-synthase

 

God bless you!

“I will praise thee; for I am fearfully and wonderfully made: marvellous are thy works; and that my soul knoweth right well.” Psalms 139.14

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