# What Is the Dependent Variable of an Enzyme?

By Robin HigginsAn independent variable equals the one that you manipulate and you are in control of. Find out about the dependent variable of an enzyme with help from an experienced biology and chemistry professional in this free video clip.

### Transcript

Hi, I'm Robin Higgins, and this is "what is the dependent variable of an enzyme?" Okay, so no matter what you're measuring, enzyme, just your basic graph, anything, really, it's always good to know independent from dependent variables. So, independent variable equals the one that you manipulate, so the one that you're in control of. And, dependent is the one that you measure. Okay, so let's look at a couple of examples. Let's say you have your enzyme, and what you're going to do is measure the rate of reaction at different pHs. Let's say this is zero, this is 14, you have seven right here. So, you start really acidically, and so the pH is the independent, because that's the one you're manipulating. You completely control what pH your enzyme is, is at, but you don't control what the rate is. That's what you're trying to figure out. So, let's you start really acidic, and there's basically no rate of reaction, it's too acidic for it. and let's say, as you kind of raise it more to neutral, it's a little better, and as you raise it to basic, around let's say, I don't know, eight or nine, it's great, and then it starts to go back down again. So, if we draw our curve, we can see that our best pH is around nine. Okay, so, this would be independent and this is dependent. So, we don't have to just measure pH and rate, we could also just change the temperature. And, let's say we could also just measure the percent of denatured protein, or enzyme, which basically means it's lost 3D's structure. So, let's just say that we're gonna be moving this from maybe 50 degrees Celsius to 100 degrees Celsius. Okay, so again, here, is the independent variable, the one that you're controlling, and the one that you don't control, the one you're measuring is here. So, another way of thinking this is that independent is always X, and dependent is always Y. Okay, so now, we have this going on, and let's say that the graph, we end up getting looks just like this. So, we can see around 70 degrees Celsius, that's gonna be the most denatured, so the worst, and then at cold and hot temperatures, it's not denature at all, so it'll work. And, most enzymes don't work like this, that's okay. It was just theoretical. Okay, so independent, X, the one that you measure, dependent, Y, the one that you, the one that you are measuring, and right here. So, independent, manipulate, Y, measure. I'm Robin Higgins and this is "what is the dependent variable of an enzyme?"