Louis Pasteur's experiments, if you recall, proved that life can arise from only pre-existing life. Can we correct this as life evolves from pre-existent life or otherwise we will never answer the question as to how the first forms of life arose? Comment.

Who showed that life comes only from pre-existing life?

The idea that life originates from pre-existing life is referred as

What is biogensis? Who proposed life is always formed from pre-existing life?

The hypothesis that "Life originated from pre-existing non-living organic molecules" was proposed by

Give some examples of data that you can collect from your day to day life.

From your knowledge of physiology can you think of some method of increasing the life of cut plants in a vase?

In 1953 S. L. Miller created primitive earth conditions in the laboratory and gave experimental evidence for organic of first form of life from pre-existing non-living organic molecules. The p[rimitive earth conditions created include: hight temperature, volcanic storms, non-reducing atmosphere

Diamond and Graphite are two allotropic forms of carbon. Both are covalent solids. These two froms have different structures and hence differ in physical properties. Both have their own importance in being used in everyday life. Diamond is popularly used in jewellery and graphite is extensively used as electrodes in many industrial processes. Answer the following questions Which of the allotropes is a good conductor of electricity.

In an experiment to estimate the size of a molecule of oleic acid 1mL of oleic acid is dissolved in 19 mL of alcohol. Then 1 mL of this solution is diluted to 20 mL by adding alcohol. Now 1 drop of this diluted solution is placed on water in a shallow trough. The solution spreads over the surface of water forming one molecule thick layer. Now, lycopodium powder is sprinkled evenly over the film and its diameter is measured. Knowing the volume of the drop and area of the film we can calculate the thickness of the film which will give us the size of oleic acid molecule. Read the passage carefully and answer the following questions : How will you calculate the volume of n drops of this solution of oleic acid ?

Read the given passage and answers following questions : The cleansing action of soap is due to emulsification and micelle formation. Soaps are basically sodium and potassium salts of long chain fatty acids, R-COO- Na^(+) . The end of the molecule to which the sodium is attached is polar in nature, while the alkyl-end is non-polar. Thus, a soap molecule contains a hydrophilic (polar) and a hydrophobic (nonpolar) part. When soap is added to water containing dirt, the soap molecules surround the dirt particles in such a manner that their hydrophobic parts get attached to the dirt molecule and the hydrophilic parts point away from the dirt molecule. This is known as micelle formation. Thus, we can say that the polar group dissolves in water while the non-polar group dissolves in the dirt particle. Now, as these micelles are negatively charged, they do not coalesce and a stable emulsion is formed. How many parts of soaps exist ?