Suppose that an aspartic acid (aspartate) residue in the active site of an enzyme was mutated to alanine. As expected, the alanine mutant was inactive, suggesting that the aspartic acid residue was critical to the catalytic mechanism.
Which mutation is most likely to restore wild-type level of activity to the alanine mutant?

a) A toY
b) A to E
c) A toL
d) A to M
e) A to K

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

since electrons are negative the answer is neagtaive

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.