Life

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cheek cells
cheek cells
diagram animal cell
diagram animal cell
what a membrane is like
what a membrane is like
motor protein
motor protein
ribosome
ribosome
diagram plant cell
diagram plant cell
propulsion of a bacterium
propulsion of a bacterium

Life

Spontaneous generation was disproven by Pasteur in 1860 - one year after Darwin publishes his 'On the origin of species'. Darwin wrote later about a 'warm little pond' where the first living cell could have originated.

Is it possible to prove Pasteur's experiments wronf or do we have to conclude that life can only spring from life? Is abiogenesis possible and do we see any proof for it?

Steps into abiogenesis

Spontaneous generation was considered almost self-evident for a long time-until one scientist after another step by step disproved the concept - even in bacteria, even if all chemicals needed are present. Still many scientists assume that abiogenesis (another word for spontaneous generation) did take place, but that the circumstances were different. Almost all of the experiments in this field are related to the origin of simple organic molecules, but that is only step 1. You can discern at least seven steps in this process:

  1. Step 1: amino-acids and building blocks of DNA - if they come into being spontaneously, we find left- and right-handed varieties (see below the links).
  2. Step 2: organising of monomeres (building blocks) into polymeres (proteins and DNA). Problem: random processes break down most of it and all kinds of unwanted chemicals will be formed. Decline and chaos is what usually happens in nature - unless directional building up can be done (using information).
  3. Step 3: After polymerisation proteins usually are folded in a specific 3D shape (sometimes inside special folding boxes), decorated with sugar chains and often joined to other molecules (proteins and other stuff).
  4. Step 4: organising polymeres like DNA and proteins in more complex structures with a membrane around it (the proto-cell). Problem: we don't know how this can be done without directional use of energy and without an information code.
  5. Step 5: enzymes have to see to it that all kinds of processes in the cell go in the right direction and the right speed (they katalyse), which is also necessary in step 7. Using RNA for katalysing itself seems less likely: RNA is unstable.
  6. Step 6: deliberate and directional exchange of molecules - gatekeeper proteins are necessary.
  7. Step 7: self-replication - an information code is necessary. Without this step there won't be any follow up and natural selection cannot work.

No real viable mechanisms are available. Some decades ago a scientist suggested a special syntropic power in matter (working against the natural tendency to chaos and falling apart) - but there's not a shred of evidence. Polyphylists will suggest this is beyond science.


Below: A minimum cell needs a minimum number of  steps to be able to function properly

Watch the video "Inner Life of the Cell" and be impressed by the sheer complexity of the cell - and of life in general. The cell is filled with purposeful structures.

Even simple organic molecules can have two varieties  - only one of these can be used in living cells


Proteins have to be folded in the right way - for some proteins special folding boxes exist

Links:

  1. Wikipedia on Abiogenesis
  2. Wikipedia on Spontaneous Generation
  3. Take a look at All about Spontaneous Generation
  4. Several articles about origin of life
  5. For more Dutch links go to: 'leven'


Origin of life and God filling the gaps?

Some people will say more research will lead to more understanding: we will less and less need God to fill the gaps. But in this case it seems to be the other way around. In former times it seemed so easy to believe in spontaneous generation, but first Redi, than Pasteur proved the idea wrong. More research has lead to the conclusion that we less and less understand how such complicated cells could be born by chance, by natural processes out of inanimate matter.

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