4 Soap has the ability to get rid of stubborn oily dirt Why

4. Soap has the ability to get rid of stubborn, oily dirt. Why is water alone not efficient for removing oily dirt? Why is warm water better than cold water in removing oily dirt?

5. Humans have about 6 billion base pairs of DNA in every cell. Based on the length of a base pair within double-stranded DNA, how many meters of DNA do we find in a human cell?

Based on what you know about the length of a base pair of DNA, how many meters of DNA do we find in the human genome?

1 m = 1000 mm; 1mm = 1000um; 1um = 1000 nm

Solution

4.Soaps are made of sodium or potassium fatty acids salts, produced from the hydrolysis of fats in a chemical reaction called saponification. Each soap molecule has a long non polar hydrocarbon chain, \'tail\' away from water, with a polar carboxylate \'head\' near to water. In water, the sodium or potassium ions float free, leaving a negatively-charged head. Soap is an excellent cleanser because of its ability to act as an emulsifying agent. Emulsifying agent is the one which helps to mix two non mixable subastances.

Hot water is better at removing stains compared to cold water because, hot water dissolves fats and oily based stains and removes them from the clothes. Fats have a low melting point of 21 to 36 degrre centigrade.

5. The distance between two base pairs of DNA is about 3.4 Angstroms.

1 Angstrom = 0.1nm

1 angstrom = 0.0001 micrometers or 1*10^-7 millimeters or 1*10^-10 meters.

Total length of dna is 6billion * 3.4angstroms or 6billion *3.4*10^-10 meters which equals 2.04meters.