Tech

At the dawn of life, heat may have accelerated cell division


An elegant ballet of proteins that allow modern cells to regenerate themselves. During cell division, structural proteins and enzymes coordinate DNA replication, division of the cytoplasmic component of the cell, and the formation of cell membranes. Correct execution of these procedures is important because errors can lead to abnormal or nonviable daughter cells.

Billions of years ago, the same challenge faced the first self-organizing membrane bundles of chemical substances that arose spontaneously from inanimate materials. But these protocells almost certainly have to regenerate without relying on large proteins. How they did it is an important question for biologists and astrophysicists who study the origin of life.

“If you delete all the enzymes in the cell, nothing happens. They’re just bare sacks,” Anna Wang, an astronomer at the University of New South Wales in Sydney. “They’re really stable, and that’s the point.”

However, in a recent newspaper in Journal of biophysics, Romain Attal, a physicist at the City of Science and Industry in France, and cancer biologist Laurent Schwartz of the Paris Public Hospital have developed a series of mathematical equations that model the extent to which only Heat may be enough to drive an important part of the regenerative process: the fission of a protocell into two.

Attal suggested that the chemical and physical processes that operated in early life were probably quite simple, and that thermodynamics alone could therefore have played an important role in how life began. . He says the kinds of fundamental equations he’s working on can explain some of the rules that govern how life first appeared.

“Temperature gradients are important for life,” Attal said. “If you understand a subject, you need to be able to write down its principles.”

Flipping for Fission

For primitive cells to divide on their own without complex protein machinery, the process would require a physical or chemical driver. “It’s really getting rid of the basic functions and thinking of a cell, ‘What are the basic physical and chemical principles, and how can we mimic that,” says Wang. without protein?’.

Figuring out these processes becomes more difficult when you consider that scientists are still unable to agree on a definition of life in general and of protocells in particular.

What scientists do agree is that protocells must have some kind of genetic information that they can pass on to daughter cells, a metabolic process that carries out chemical reactions, and a membrane. lipids separate metabolism and genetic information from randomness in the rest of the early Earth. While the outer chemical world is inherently random, the division provided by lipid membranes can create a region of lower entropy.

For a protocell to grow before dividing, it would have to increase not only the volume inside the cell, but also the surface area of ​​the surrounding membrane. To create two smaller daughter cells with the same total volume as the parent cell would require extra lipids for their membranes, since their surface area would be larger than their volume. The chemical reactions needed to fuel the synthesis of these fats produce energy in the form of heat.

As Attal discussed these ideas with Schwartz, he began to wonder if this energy would be enough to drive early cell division. A search of the research literature reveals a finding that mitochondria (the energy centers of the cell, which began as a symbiotic bacterium billions of years ago) have a slightly higher temperature than surrounding cells. Attal wanted to know if that energy difference could be created in the protocell, and if it would be enough to drive fission.

.



Source link

news7g

News7g: Update the world's latest breaking news online of the day, breaking news, politics, society today, international mainstream news .Updated news 24/7: Entertainment, Sports...at the World everyday world. Hot news, images, video clips that are updated quickly and reliably

Related Articles

Back to top button