Question

After being heated, an enzyme loses its ability to catalyze a reaction. What change occured to the enzyme?

a. A chemical change, because the chemical bonds between its atoms were broken.

b. A chemical change, because it can no longer react in the same way.

c. A physical change, because intermolecular forces were overcome.

d. A physical change, because cooling will restore the enzyme's function.

Answer 1

Personally, I believe the answer is A.

Answer 2

Temperature affect the weak (intermolecular) forces which are vital in maintaining the 3D shape (or conformation) of the protein. As temperature increases the catalytic activity also increases up to a point. When the intermolecular forces are disrupted and the enzyme looses its conformation, that is it becomes denatured, the catalytic activity will sharply drop.

Answer 3

So it would be C? I though heating was a chemical change?

Answer 4

i am not sure

Answer 5

It says it is reversable in very few cases, renaturation. So i think chemical change.

Answer 6

Heating something in general really is a physical change, but reading about this protein thing some, it sounds like a chemical change. The activation sites are altered by the heat.

Answer 7

Yeah it is a weird question. Given that it is a chemical change, if it actually is, I'm not sure whether to go with A or B. If the enzyme loses its ability to catalyze a reaction, than it can't react in the same way.

Answer 8

@DanJS The answer was C just in case you were wondering.

Answer 9

It's definitely not A and definitely not D, because the problem clearly states that you provided heat.

Physical change is a change in which a substance changes from one physical state to another but no substances with different composition are formed. Hence, C is your answer.