The Urey-Miller experiment conducted in 1953 aimed to test the hypothesis that basic biomolecules could form from simple gases on the early Earth. Stanley Miller and Harold Urey created a setup to simulate early Earth conditions, exposing a mixture of gases including methane, ammonia and hydrogen to electric sparks. The resulting organic soup was found to contain amino acids like glycine and alanine, demonstrating prebiotic synthesis of key building blocks of life from simple starting materials. This experiment supported the hypothesis that life may have originated from natural chemical processes on the early Earth.

1. UREY-MILLER EXPERIMENT
SONIA JOHN
I M.Sc. Zoology
Mar Ivanios College

2. INTRODUCTION
• Experiment simulated the conditions thought at
the time to be present on the Early Earth
• Tested the chemical origin of life
• Tested Oparin&Haldane Hypothesis
• Classical experimenting investigating abiogenesis

3. EXPERIMENT
• Conducted in 1953 by Stanley Miller& Harold Urey

4. EXPERIMENTAL SET-UP
• Special flask: ; Glass flasks connected in a loop
with one flask half-filled with water & another
flask containing a pair of electrodes.
• Mixture of gases: NH3,CH4 and hydrogen
taken in the flask
• Boiling water.
• High frequency spark by tungsten electrodes
• Condensor

5. APPARATUS

6. EXPERIMENT
• Steam from the boiling water mixes with the
other gases in the apparatus
• This is passed into the section containing the
electrodes and the spark
• The steam and the mixture of gases is cooled
down via the help of condensor and flows
back to the boiling water flask.

7. RESULTS
• The resulting fluid collected was analysed
• The mixture consisted of :
• amino acids like glycine, alanine,aspartic acid
• Sugar molecules
• Purines,pyrimidines etc

8. CHEMISTRY OF EXPERIMENT
• One step reaction among mixture components
can produce hydrogen cyanide , formaldehyde
CH4 +2[O] CH2O + H2O
CH4+NH3 HCN + 3H2

9. CHEMISTRY OF EXPERIMENT
• The formaldehyde , ammonia , & HCN react
to form amino acids & other biomolecules.
CH2O+HCN+NH3 NH2-CH2-CN + H2O
NH2- CH2-CN+2H2O NH3+ NH2-CH2-COOH
(Glycine)

10. SIMILAR EXPERIMENTS
• 1961 Joan Oro- Adenine could be made from HCN
and NH3 in a water solution.
• Many amino acids are formed from HCN and ammonia under
these conditions.
• Experiments conducted later showed that the other RNA and
DNA nucleotide bases could be obtained through simulated
prebiotic chemistry with a reducing atmosphere.

11. What The Experiments Indicate
• Electric discharges produced during lightening in the early
atmosphere containing ammonia, nitrogen .methane
,hydrogen, water etc might have resulted in the formation of
amino acids and other complex components of living systems
in the soupy sea.

12. CONCLUSION
• The Miller-Urey experiment stimulated condition
thought at time to present on early earth & tested
for occurence of chemical origin of life’. In 1953
Stanley Miller & Harold Urey conducted experiments
on the chemical origin of life. This experiment was
helpful in understanding the condition of Earth’s
early atmosphere.

13. REFERENCES
• Charlotte.J.Avers .1989. Process and pattern in evolution.
Oxford University Press.
• Mohan .P.Arora .2000.Evolutionary Biology.Himalaya
Publishing House.Delhi
• Veer Bala Rastogi. Organic Evolution(1st edn).Kedar Nath
Ram Nath,Meerut
• http://en.wikipedia.org/Miller-Urey Experiment