Saturday, November 21, 2020
We have no idea how life on Earth began
My late Aunt, Dr Jean Youatt (1925-2017), was a very well-respected
microbiologist in Australia;
recognised by the Australian Acadamy of Science in 2000 for her
  ground-breaking achievements as a female scientist. Don't ask me why now but, it has occurred that this would be a good place to
post the eponymous item that she wrote many years ago but only sent me in the
year before she died. I believe it speaks for itself:
This outline needs knowledge of Chemistry and Biochemistry to follow the
  arguments. A non-scientist will need to refer to literature or consult
  knowledgeable people.
Evolutionary biologists avoided this difficult subject even after structures
  of proteins and nucleic acids became well known. But it has been admitted by
  Professors Davis, Reese and Dawkins recently on TV that we have no idea how
  life on earth began. The simplest form of life that can reproduce itself is a
  bacterium and for one of them to form there would have to be together in one
  place the many components required for one bacterium. There has to be a wall
  which separates the organism from its environment and all the walls we know
  are complex structures with polymers involving proteins, lipids and
  polysaccharides. Inside the cell there have to be proteins and nucleic acids.
  The nucleic acids consist of long chains of sugars ribose in RNA and D ribose
  in DNA linked by phosphate ester bonds and for each sugar molecule a purine or
  pyrimidine base is attached to the sugar and it takes three of these bases to
  code for each amino acid in a protein.
We consider the structure of RNA. Ribose is a sugar with 5 carbon atoms. If
  it is drawn as an open chain it has 3 chiral atoms (related as mirror images)
  and thus 23 different structures possible = 8. In the nucleic acid structure
  the sugar is in a ring form and two rings are possible and known. Forming a
  ring makes a new chiral centre raising our possibilities to 16 but the ring
  can be made of 5 or 6 atoms so now 32 possibilities and then with RNA there
  are 2 ways the phosphate ester linkage can form so 64 possibilities. In the
  living cell the ribose rings are all identical and there are millions of them
  needed in just one cell. The deoxyribose of DNA forms a 5 membered ring too
  but has one less chiral atom and one way to form the phosphate link so 16 ways
  to form and this too requires millions of identical forms in the DNA.
In the code for making proteins there are just 5 bases used and they must be
  in a specific order to define a proteins structure. The atoms which form the
  bases could come together in many other forms further increasing the huge
  number of atoms which have to form in such a specific way.
"Similarly when we come to consider proteins there are 16 common amino acids
  but many other possibilities and proteins which can have 200 amino acids have
  to have them in the right order to perform their function. There may be 2000
  proteins required. Amino acids formed by chemical reaction which are always a
  mixture of 2 chiral forms, that is molecules related to each other as mirror
  images which cannot be superimposed. Proteins use only one of these two forms
  commonly referred to as the L form. The D and L forms have all the same
  chemical and physical properties and so cannot be separated by any common
  methods. They can be separated by using reaction with other chiral atoms which
  form by enzyme reactions in living cells and in no other way. Sometimes
  partial separations have been claimed but not when everything used has been
  rigorously freed of all organic compounds and the medium kept sterile
  throughout the experiment.
Now we have to assume that all the essential structures are in one place at
  one time because if they form by chemical reactions the processes are
  reversible. This may suffice to show that for a viable organism to come
  together there is an astronomical number of alternative structures from which
  just one must come. It is worth mentioning that for 60 years or more
  scientists have made mixtures of L amino acids, D sugars, vitamins, purine and
  pyrimidine bases etc required to grow human cells and cells have been grown
  without any reports of new life forms emerging. Thus for the scientist asking
  “Did life emerge by chance or was there a creator?” the only position possible
  is “I don’t know” and individuals can choose a creator or chance theory to
  their taste.
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