Question

State the theory of biogenesis. How does Miller’s experiment support this theory?

Answer 1

Hint: The theory of biogenesis was proposed by Louis Pasteur which states all life originates from pre-existing life.

Complete Answer:
- Theory of biogenesis was proposed by Louis Pasteur. He stated that all life forms originated from pre-existing life. He also stated that these cells further originated from the organic molecules such as RNA and proteins.The formation of life was preceded by the chemical evolution. The term ‘biogenesis’ is derived from the word ‘bio’ meaning ‘life’, and ‘genesis’, meaning ‘beginning’.

- Pateur boiled a meat broth in a flask that had a long neck that curved downward, then upward, like a swan-neck flask. The bend in the neck prevented contaminating particles from reaching the broth, but allowed free diffusion of air.

- Pasteur's flask remained free of bacterial growth for as long as the flask remained upright. But, when he tipped the flask enough for the broth to sweep out the bend in the gooseneck; the broth would then quickly become clouded with bacterial growth.

- In 1953, Stanley Miller, student of Harold Urey conducted an experiment to prove the theory of biogenesis. He set up the experiment,but created conditions of primitive earth in the laboratory. An electric discharge was stimulated into a closed flask containing methane, hydrogen, and ammonia at 8000°C. He observed the formation of amino acids and ultimately proteins. This proved that life originated from non-living components.

Note: Louis Pasteur is said to disprove the theory of spontaneous generation with his famous swan-neck flask experiment.