How are cell death like apoptosis and entropy related?

Question

In Perspectives on Statistical Thermodynamics, Yoshitsugu Oono, it is written that

Do not conclude, however, that since the second law is invincible, information thermodynamics is unimportant. It is possible for a system we are interested in to perform something that ordinary thermodynamics does not allow, and to pay the price somewhere else. For example, it may be possible to go beyond the limit of thermodynamics for the time being by shifting the average value of fluctuations, although the price must be paid (dearly) later. There must be such cases in molecular machines. It is argued that cell senescence is due to the accumulation of defects and wastes, but cell death could have a more active implication of carrying away the debt caused by utilizing information. Thus, entropic apoptosis and entropic altruism are conceivable.

but I don't understand the following two points.

• Why is cell death associated with "debt caused by utilizing information"? Do cells die for increasing entropy to compensate the entropy decrease which caused by their using information (but what kind of information)?
• Why can we conclude "Thus, entropic apoptosis and entropic altruism are conceivable."? Does this mean, to let other cells decrease the entropy by consuming information, some cells kill themselves to increase entropy?

Answer 1

Unless you have a closed system, don't bother with the second law. These sound like some poetic descriptions but they won't tell you much about biology.

It is argued that cell senescence is due to the accumulation of defects and wastes, but cell death could have a more active implication of carrying away the debt caused by utilizing information.

The first part of sentence which I italicized here is sufficient to understand the biology: cells age and die off because they accumulate defects. Organisms, whether single-celled or multi-celled, ultimately get around this by making lots of copies of themselves and expecting some to fail.

The second part of that sentence says "could" and is poetry to describe the first half, as well as the sentence that follows. It doesn't add any more science, unless you care about the existence of "entropic altruism" in the universe, which sounds to me like a religious rather than scientific approach. It's just stating that cell death (and perhaps, to an extension, death of multicellular organisms) can be useful to organisms/species rather than merely destructive. There is nothing wrong with finding beauty in physics and mathematics, but beauty in itself says nothing about how things work or how things should be.

In the context of a multicellular organism, cells kill themselves to not kill/harm the whole organism (e.g., to not develop into cancer, or as a planned event during development). The biological reason they do this is because multicellular organisms that have evolved genetic mechanisms to identify potentially harmful cells and have those cells die are more likely to reproduce and produce more multicellular organisms like themselves. If you want to interpret this as "entropic altruism" because cell death increases entropy, that's fine, but no thermodynamic argument is needed or even all that helpful in explaining the biology.

Note also that the book you cite doesn't seem to be in common use; it has no reviews on Amazon or Google books, and a previous book by the same author only has 1 review. I don't have anything against the author and they could be an excellent statistical physicist, but language like this makes me think they are not a biologist.

Answer 2

As far as I know, apoptosis has nothing to do with entropy, except in the degenerate and trivial case where a cell is utterly voided of energy for enough time that it stops working.

Entropy is informally defined as a low-energy state. Cells that are low on energy are typically designed to pick up more energy from the environment. A simple example: Consider a cell that metabolizes glucose into an organic acid for energy. Assume that the cell lives in an environment where glucose is readily available, organic acids are regularly cleared away, and it has transport protein channels that readily allow glucose and organic acid waste-products to cross the membrane.

As the cell uses its own glucose for energy, it gets converted into an organic acid (waste product) which builds up in the cell. Now the cell has a lower concentration of glucose than its surrounding environment - and due to the transport protein channels, glucose from the outside will tend to move into the cell down the concentration gradient. Likewise, as organic acid waste-products accumulate, they tend to exit the cell over their own protein channels because the concentration of acids in the cell is higher than its environment.

Higher-order life forms (extremely complex with billions of highly differentiated cells) implement apoptosis as a form of quality control over cells. Over time, cells accumulate damage and mutations. Exact mechanisms vary significantly by species. In humans, there are specific proteins that scan for nonrepairable damage to protein structures in cells or dangerous DNA mutations. In some cases, a cell may be programmed to stop replicating itself; extremely dangerous (oncogenic) mutations may trigger apoptosis where the cell "takes one for the team".