Question

With respect to proteins, a change in pH cannot alter:

primary structure

All of the above

quaternary structure

tertiary structure

secondary structure

Which of the following statements about phospholipid molecules is false?

None of the above

phospholipases can switch the acyl groups as well as the head groups

have different head groups

have glycerol backbone

should have palmitate as one of the acyl groups

Answer 1

1. Primary structure

Every protein work at a given range of PH called as optimum pH. Any increase or decrease in this optimum value is detrimental to the structure of protein and results in the loss of its function. This is because at extreme pH, the three dimensional structure of enzyme is lost thereby the protein get unfolded. In this process all the bonds, hydrophobic interaction, hydrophilic interaction and hydrogen bonds are broken. Only one type of Bond remains intact, that is the covalent peptide Bond. Because of this the primary structure of protein remains intact.

2. have different head groups

Phospholipids are molecules made up of phosphate head which is the hydrophilic part and fatty acid tail which is the hydrophobic part. Apart from fatty acid tale, they may have alcohol also. Fatty acid tail is formed by esterification of glycerol and fatty acids.

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