Biochemical origin of life - modern concept, PL-SQL Programming

BIOCHEMICAL ORIGIN OF LIFE -

  • It is generally agreed by astronomers, geologists and biologists that the earth is approximately 4500-5000 million years old.
  • It is an opinion of a large section of biologists that the original state of the earth bore little resemblance to its present day and had the following probable appearance:
  • It was hot about 4000-8000°C and as it cooled, carbon and the less volatile metals condensed and formed the core of the earth.
  • The surface was probably barren and rugged as volcanic activity, continuous earth movements and contraction on cooling, folded and fractured the surface.

1924_biochemical origin of life.png

  • The atmosphere is believed to have been totally different in those days.
  • The lighter gasses hydrogen (H), helium (He), nitrogen (N), oxygen (O) and argon (Ar) would have escaped because the gravitational field of the partially condensed planet would not contain them..
  • But simple compounds containing these elements would have been retained e.g., water (H2O), ammonia (NH3), carbon dioxide (CO2), methane (CH4), and until the earth cooled below 100°C all water would have existed as vapour. 
  • First molecular compound formed were H2O & NH3.
  • First organic compound formed was CH .
  • Free oxygen was absent. Therefore primitive atmosphere was reducing.
  • The chemical theory of life was elaborated by two workers independently.
  • A. I. Oparin (1923) and J.B.S. Haldane (1929) and was summarized by oparin in his book "The origin of life".
  • They held that Spontaneous generation of life under the present environment conditions is not possible.
  • Earth's surface and atmosphere during the first billion years of its existence were radically different form today's conditions.
  • Earth's initial atmosphere was a reducing one.
  • The first life arose from a collection of chemical through a progressive series of chemical reactions in which atoms combined into inorganic molecules, inorganic molecules into simple organic compounds, and simple organic compounds into complex organic compounds, which finally got organized into the living matter.
  • The sequence of changes an 8 step process, begins right from the formation of earth.

 

2346_biochemical origin of life1.png

  • Solar radiation, heat radiated by earth and lightning provided energy for evolution of molecules.
  • The Oparin-Haldane theory was experimentally supported by Stanley Miller in 1952.
Posted Date: 10/8/2012 8:44:06 AM | Location : United States







Related Discussions:- Biochemical origin of life - modern concept, Assignment Help, Ask Question on Biochemical origin of life - modern concept, Get Answer, Expert's Help, Biochemical origin of life - modern concept Discussions

Write discussion on Biochemical origin of life - modern concept
Your posts are moderated
Related Questions
FETCH Statement The FETCH statement retrieve rows of data one at a time from the result set of the multi-row query. The data is stored in fields or variables which correspond t

Database Values You can use the SELECT statement to have the Oracle assign values to a variable. For Each and every item in the select list, there must be a matching, type-compa

Number Types The Number types permit you to store the numeric data (real numbers, integers, and floating-point numbers), show quantities, and do computations. BINARY_INTEG

Wrapping and unwrapping in SQL Operators WRAP and UNWRAP in connection with attributes whose declared types are tuple types. Example shows how extension and projection can be

Using SET TRANSACTION You use the SET TRANSACTION statement to begin the read-only or read-write transaction, start an isolation level, or assign your present transaction to a

Case Sensitivity Similar to all the identifiers, the variables, the names of constants, and parameters are not case sensitive. For illustration, PL/SQL considers the following n

Stored Subprograms Normally, tools (like Oracle Forms) which incorporate the PL/SQL engine can store subprograms locally for later, strictly local execution. Though, to become

Complete the following steps to create a procedure to calculate the tax on an order. The BB_TAX table contains the states that require taxes to be submitted for Internet sales. If

DELETE Statement The DELETE statement eliminates whole rows of data from the specified table or view. Syntax:

Write a query to find academics that are authors and that have only ever coauthored papers with authors from institutes in the same state as their own. List their academic number,