In a particular enzyme, an alanine residue is located in a cleft where the substrate binds. A mutation that changes this residue to a glycine has little effect on activity; however, another mutation, which changes the alanine to a glutamate residue, leads to a complete loss of activity. Provide a brief explanation for these observations.

Explanation:

There are non-polar side chains also present in alanine. And, these non-polar side chains are involved in some hydrophobic interactions in active sideand then it changes into polar amino acid glutamate that will destroy the hydrophobic interaction.

Whereas in glycine there is only hydrogen present in the side chain therefore, it will not affect much.

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.