Posts Tagged ‘molecular biology’

“If a biochemist is asked to identify the one enzyme which is most vital to all forms of life, he would probably name cytochrome c oxidase,” according to American molecular biologist Earl Frieden at Florida State University.

Cytochrome c is the essential component of life’s electron transport chain. Amazingly, unlike hemoglobin with one metal atom, iron, cytochrome c is even more complex, containing four metal atoms−iron, copper, zinc and magnesium. Continue Reading

Self-organization is hot, once again.

Critical of his own work, in a letter to Hugh Falconer in October 1862, Charles Darwin wrote, “I look at it as absolutely certain that very much in the Origin will be proved to be rubbish; but I expect and hope that the framework will stand.”

For Darwin, the origin of life was the result of spontaneous generation. The twenty-first century version is now more popularly referred to as abiogenesis, or self-organization. Continue Reading

One of the biggest questions in evolutionary molecular biology is—what is the chance that a single protein molecule could have actually been formed by mere random chance?

In principle, probabilities smaller than 1 over 1,050 are thought of as having a zero probability. Since an average-sized protein molecule is composed of 288 amino acids with 12 different types of amino acids, this protein can be arranged in 10,300 different ways, which is 10 followed by 300 zeros. Since 10,300 far exceeds 1,050, the probability of the formation of only one protein molecule by random chance is zero. Molecular biologist Harold Blum concludes that from the mathematical perspective, probability of a protein autonomously assimilating by chance is zero:

“The spontaneous formation of a polypeptide of the size of the smallest known proteins seems beyond all probability.”

In The Origin of Species, Charles Darwin concurs with Blum in the larger context,

“Mere chance, as we may call it, might cause one variety to differ in some character from its parents, and the offspring of this variety again to differ from its parent in the very same character and in a greater degree; but this alone would never account for so habitual and large a degree of difference as that between the species of the same genus.”