The theory of evolution proposes that living organisms have developed greater complexity over time, originating from what are often called ‘simpler forms’. The notion of a ‘simple form’, however, is difficult to define. In reality, no form of life can be called ‘simple’.1
The vast majority of living organisms are cellular, ranging from single-celled protozoa to large, multicellular animals. Even plants and bacteria exhibit a cellular structure, although their cell walls differ significantly in composition and form.
What are metabolic pathways?
A metabolic pathway is a series of consecutive biochemical reactions occurring in a cell that result in the creation of one or more functional products. Living organisms use metabolic pathways to transform one chemical compound into another with the help of enzymes (proteins). These pathways exist in all living beings.
The molecule that begins the chemical pathway inside the cell is the substrate, which is acted upon by an enzyme. Enzymes (biological catalysts) are structured so that biochemical reactions proceed at incredible speeds.
When an enzyme binds to a substrate, the substrate breaks down into two molecules, i.e., products, while the enzyme remains unchanged and immediately binds to another substrate. These reactions occur within fractions of a second. At any moment of a cell’s life, billions of enzyme molecules transform billions of substrates into billions of products. The entirety of these reactions is called metabolism.2
Cellular pathways begin outside the cell when a ligand (a biomolecule that serves as the initial messenger) encounters a specific protein receptor suspended in the cell membrane. A large group of these receptors is called GPCR—G protein-coupled receptors3. GPCRs are designed to detect specific ligands outside the cell, initiate internal signaling pathways inside the cell, and eventually provoke cellular responses, such as protein production.
Have metabolic pathways evolved?
In Lehninger’s Principles of Biochemistry, the authors claim that all GPCR signalling mechanisms ‘must have arisen early in evolution’.4 However, the assertion that ‘they must have arisen’ explains nothing, let alone providing a scientific explanation. There is no description of the gradual origin of this complex mechanism.
Similarly vague explanations are found, for instance, in descriptions of humans’ and mammals’ sense of smell, attributed to GPCRs:
‘Little is known about the functioning of olfactory receptors in mammals or how this large family of genes evolved in response to various evolutionary challenges.’5
On the other hand, the Annual Review of Biochemistry states:
‘The emergence of pathways that now encompass central metabolism, and even intermediary metabolism, is particularly enigmatic.’6
Some evolutionists, despite their disbelief in a Creator, see evident design in these living pathways and aptly compare them to human technology. In a parasitology textbook, regarding internal cellular reactions in protozoa and many other metabolic events, the following comment appears:
‘(…) biochemical pathways resemble printed circuits of advanced electronic equipment.’7
Conclusion
Are these complex and orderly pathways a result of time and chance, or rather of plan and purpose? Only God can be the source of life, which alone accounts for the profound complexity observed at the subcellular level. The structure and interdependence of metabolic pathways undoubtedly point to Him.
By the way, we recommend reading the articles:
- The Origin of the Moon: Coincidence or Design?
- Hyperbaric Oxygen Therapy and Pre-Flood Longevity
- The Relationship Between Theistic Evolutionism and Death
- Panspermia Does Not Explain the Origin of Life
- Coprolites: Indisputable Evidence
Footnotes
- F. Sherwin, Not-So-Simple Plankton, Creation Science Update, posted on ICR.org December 13, 2018.
- R. Fani, ‘The Origin and Evolution of Metabolic Pathways: Why and How did Primordial Cells Construct Metabolic Routes?’, Evolution: Education and Outreach, 2012, 5(3): 367–381. Emphasis in original.
- F. Sherwin, ‘Those Amazing G Protein Receptors’, Acts & Facts, 2006, 35(12).
- D. Nelson and M. Cox, Principles of Biochemistry, 7th ed., 2017, New York: W. H. Freeman, p. 459.
- C. Dybas, By Dark of Night, How Do Bats Smell Their Way to Fruit?, National Science Foundation Research News, posted on nsf.org March 3, 2014.
- L. Noda-Garcia, W. Liebermeister and D. S. Tawfik, ‘Metabolite-enzyme coevolution’, Annual Review of Biochemistry, 2018, 87(1): 189.
- L. Roberts et al., Foundations of Parasitology, 9th ed., 2012, New York: McGraw-Hill Education, p. 51.
Adapted from: F. Sherwin, ‘Metabolic pathways to God’, Acts & Facts, Institute for Creation Research, March 2020, p. 14.
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