In an experiment, the rate of an enzyme-catalyzed reaction increased as the substrate concentration increased, but it leveled off after reaching a certain point. Why is there a steep slope in the beginning? why does it level off when more substrate is added?

 

I need help with this question..i have turned my bio book inside out and i still cant find the answer..i feel like it is soo simple and i am over thinking it..any help at all is appreciated

Think about the following: What compounds participate in the reaction? Could there be a limiting element? Also look up enzyme kinetics.

Without giving away the answer, imagine the enzymes as 100 permanently hungry mice. You feed them the substrate - peanuts. You time how long it takes the mice to eat the peanuts.

 

As you increase the number of peanuts again and again many times, and you draw a graph of the rate at which peanuts are eaten, what do you think will happen?

 

Remember the mice are permanently hungry...

 

OR,

 

read this Biology Revision Guide which should give you more accurate information rather than my poor analogy.