RNA Archives

September 19, 2025September 18, 2025

The Homochirality of Organic Molecules

Yesterday, we discussed the chirality, or handedness, of molecules, especially amino acids and proteins. The homochirality of organic molecules refers to their requirement for the same handedness, a mystery that has puzzled scientists since 1848, when Louis Pasteur first observed that some life-essential molecules had mirror-image forms. Amino acids used by living cells and the proteins they build have left-handed chirality, while DNA, RNA, and the sugars forming their building blocks are all right-handed. These facts raise a question for those who believe life arose spontaneously.

Left-handed proteins and right-handed DNA are found in all living organisms. The spiral structure of DNA needs to twist in a specific direction to function properly, but what caused the right-handed sugar molecules to come together? When half of all amino acid molecules in nature exhibit right chirality and the other half left, what force could have gathered only the left-handed ones to form the first proteins?

Scientists have speculated that cosmic rays or polarized light might have triggered this process. However, even if such forces created an initial bias for the same-handedness, they could not sustain and amplify it enough to produce a significant number of homochiral molecules to form the first living cells. In 1999, researchers proposed that electron spin created magnetism, causing left-handed peptides (short chains of amino acids) to bind to magnetic surfaces like magnetite. But this still did not explain how the homochirality of organic molecules could be amplified sufficiently to generate living cells.

Some scientists consider RNA to be the key to the origin of life. In 2009, a group of researchers studying RNA molecules suggested that a crystal called RAO could react to produce two of RNA’s four nucleotides. In 2023, other researchers used magnetism to produce RAO crystals with homochirality. However, this process required a magnetic field 6,500 times stronger than Earth’s magnetic field. Additionally, RAO has only been shown to produce two of RNA’s four nucleotides, still falling short of generating the complete homochirality of molecules needed for life.

As 2024 ended, NASA-funded research identified a problem with the so-called “RNA world” hypothesis. Simulating early Earth conditions, they found that RNA did not show a chemical bias toward selecting homochiral amino acids. The current thinking is that the homochirality of organic molecules “could have emerged through later evolutionary pressures.” In other words, we have the “evolution-of-the-gaps” theory because, of course, evolution can do anything you can imagine.

Currently, NASA scientists are analyzing samples brought back from asteroid Bennu, hoping that molecular evidence from meteorites and asteroids will demonstrate that the building blocks for life came from beyond Earth. I suspect that the force responsible for bringing life to Earth did originate outside our planet, and even beyond the universe.

References: science.org and nasa.gov

February 18, 2022February 15, 2022

No Life Without Water

Without water, life would not be possible. For that reason, astronomers are constantly looking for other locations in the universe where liquid water might exist. Only in such places could there be any hope of finding life. Whether life exists anywhere in the universe outside of planet Earth is a question people have asked for hundreds of years. Scientists still don’t know the answer, but everyone agrees that there could be no life without water.

The water molecule seems very simple. It is H²O–one oxygen atom combined with two hydrogen atoms. However, instead of bonding in a straight line (H-O-H), the two hydrogen atoms are on one side of the water molecule at a 104.5-degree angle from each other. That alignment gives the hydrogen side of the water molecule a partial positive charge, while the other side has a partial negative charge. Because of that, the positive and negative sides of water molecules attract one another and form hydrogen bonds resulting in a network of water molecules.

When water is in the gaseous state, the interaction between molecules is negligible. However, when it is in the solid form of ice, each water molecule forms a bond with four others, creating a lattice that causes ice to be lighter than liquid water. For most substances, the solid state is heavier than the liquid state. This unique property of water causes ice to float. Additionally, the low thermal conductivity of ice prevents the water below from freezing. If lakes and oceans froze from the bottom up, it would kill all marine life and ultimately all life on Earth.

If water molecules did not form hydrogen bonds, instead of boiling at 100 degrees C, water would boil at -100 degrees C. That would prevent life processes. Furthermore, because there is a 100 degree C difference between water’s melting and boiling points, life is possible in Earth’s wide range of environments. Water has the highest heat of evaporation of any known substance so that it remains liquid up to and even at its boiling point. It also has the second-highest heat capacity of any known substance, allowing its temperature to remain stable during heat fluctuations in the environment. Those qualities of water are also critical for life, meaning that there could be no life without water.

Water’s ability as a solvent makes it essential for the life processes of living cells. Likewise, water’s inability to dissolve oily substances is vital to create a strong “hydophobic effect.” Cell membranes, DNA, RNA, and proteins all contain oil-like regions. If the water in the cells could dissolve them, life would not be possible. In addition, the water molecule can participate in and enable chemical processes such as hydrolysis, reduction, oxidation, and others that are essential in living cells.

The bottom line is that there is no life without water and the fine-tuning of the hydrogen bonding in water molecules. With new scientific discoveries, we see fine-tuning for life in the cosmos and even in the cells of our bodies. Without that fine-tuning, life would not exist, and we would not be here. Accidental coincidences do not explain such incredible precision of design. We think the explanation goes beyond science and points to an intelligent Designer.

For much more on this, read chapter three, “The Chemical Anthropic Principle,” in Fazale Rana’s book Fit for a Purpose.

October 23, 2017November 8, 2018

Origin of Life Complexity

The origin of life complexity continues to baffle science. There are two competing scientific theories on the origin of life. One is called the “Darwin school of thought” which posits that meteorites brought elements to Earth that led to the formation of compounds which led to RNA and then to DNA. The second theory says that life originated in mineral-rich hydrothermal vents on the ocean floor.

The problem with both of these theories is that they are not explaining the origin of life complexity. They are only explaining some of the compounds that would be necessary to form life. Many scientists question the possibility of either of these theories and whether organic compounds could survive in the conditions of the early Earth. The bigger issue is how you could move from those compounds–no matter how they were formed–to a living cell.

You not only must have the ingredients to make life, but you also need a protected environment in which those compounds can be combined. Life could not begin in a toxic atmosphere or if there were agents on Earth’s surface that would destroy the ingredients. RNA and DNA involve long strands of nucleotides. Scientists in the laboratory can only produce such chains in a carefully controlled environment. The time element involved in producing increasingly complex molecules is also an issue.

When we enter probabilities into this process, the odds of each step happening by chance are very unlikely. Then to put all the steps together in the right order makes the probability of it happening by chance outside the scientific limits of what is possible.

Research into the origin of life complexity strongly points to an intelligent Creator. The more we learn, the more complexity we see. The famous atheist Antony Flew saw the complexity of a living cell, and that was a major factor in his coming to believe in God. His statement of faith was, “You have to go where the evidence leads.” Certainly, this area of study gives evidence of God’s wisdom and creative design. References: The Week, October 20, 2017, page 19, and Newsweek.com.
–John N. Clayton © 2017