LUCA and its Leaky Membrane

Chemiosmosis Theory is probably the most important biological theory full stop. It’s this utilisation of a proton flow across a membrane by a particular enzyme (ATPsynthase) to generate the molecules of  ATP. These ATP molecules are vital for any cellular process as it provides the energy for metabolic reactions.

Yet what’s incredible about this particular utilisation of protons, is that it is present in each living cell in every living organism on Earth, including single celled organisms such as Bacteria and Archaea.  This means that sometime during evolutionary time,  a common ancestor for every species since has evolved the ability to utilise chemiosmosis. We shall refer to this ancestor as the ‘Last Universal Common Ancestor’, or LUCA. chemioThe argument has been that LUCA would not have been able to generate ATP as after the protons diffuse in to the cell, the concentration gradient would be reversed resulting in an isotonic solution with equal proton concentration outside and within the cell. Thus no chemiosmosis to generate ATP.

However a single study has theorised that if LUCA’s plasma membrane was leaky it would be able to continue to utilise chemiosmosis:  http://www.ucl.ac.uk/news/news-articles/0814/130814_LUCA_leaky_membrane

 

 

Mathematical Chaos and Evolution

With Darwin’s Natural Selection being the most renowned and taught evolutionary theory, are we limiting our perspective on evolutionary mechanisms and progression?

A double rod pendulum animation showing chaotic behaviour. Starting the pendulum from a slightly different initial condition would end in a completely different outcome.

 

http://www.newscientist.com/article/mg20827821.000-the-chaos-theory-of-evolution.html?full=true#.VGtDSrdFC1s

Chaos theory studies the behaviour of dynamic (yet deterministic) systems that are highly sensitive to initial conditions—a response often referred to as the butterfly effect. Mathematically speaking, Chaos Theory could provide an insight in to this progression due to species populations and allele frequency being chaotic in discrete circumstances.  Therefore minute alterations in initial conditions will result in drastically contrasting outcomes.

Before reading the linked article consider that  biological systems express the following properties of chaotic systems:

  1. ‘It must be sensitive to initial conditions’
  2. ‘lt must be topologically mixing’ (There is a continuous combination of factors/conditions)
  3. ‘It must have dense periodical orbitals’ (There are repeated cycles and patterns over time)

 

“We can do science, and with it, we can improve our lives…” Carl Sagan

Follow

Get every new post delivered to your Inbox.

Join 263 other followers