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Enzyme Lab - Introduction

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Heights mr. Anderson welcome to AP biology lab 2 walkthrough this is on enzyme catalysis set basically the enzyme lab the enzyme that will be studying this something called catalase catalyze is an enzyme that's found in almost all living things and its job is to break down this chemical this chemical looks a lot like water but we got an extra oxygen so this is hydrogen peroxide and so if you ever skin your knee when you're growing up and your mom put peroxide on it what you found is that it started to bubble and the reason it was bubbling is that this enzyme is found in almost all living things and it breaks down hydrogen peroxide into water oxygen Bubbles and so is it cleaning the moon probably not more than water but it made me feel good when I was a little on the enzyme it will be using from yeast soak a delays from yeast in this experiment basically we should talk about what an enzyme is an enzyme is going to be a biological molecule that acts as a cat a catalyst is going to be any chemical that speeds up a reaction but it's not really consumed in the reaction itself it's not a reactant or a product I'll let me give you an example of that if you can drink milk in and you don't feel sick then you have an enzyme that functions called lactase lactase is going to break down a disaccharide a lactose sugar that's found in milk so basically the lactose will fit into the enzyme almost like a key in a locked it's going to then put a little chemical tug on it just going to break that lactose down into its Two Sugars and so if you look at the enzyme itself the lactase it's never changing its shape it's just receiving a substrate we call that or a molecule that fits into an enzyme it breaks it apart and then it waits for another one over and over and over again and for things like lactase this can happen millions of times second toe goes really really quickly and so in this experiment what we're going to use is catalase Oak a delays is an enzyme what's a breakdown it essentially brakes hydrogen peroxide or h202 it's going to take that in as a substrate and it's going to break that down into two things it's going to break that down into H2O and then oxygen or those little oxygen bubbles in it happens at the rate of millions of times the second and so in this lab basically what we're going to do is we're going to take a little bit of filter paper and then we're going to dip it in different concentrations of yeast we're going to dip it into concentration of used where there's no yes so we called that zero and then we're going to increase the concentration the Beast will then take that filter paper and we're going to drop it into a beaker but that Beaker is going to contain hydrogen peroxide okay what happens now we're going to put that little it's going to sink down to the bottom and said there's no East on it what's going to happen well that filter paper is going to sit at the bottom forever it will never float because there's no enzyme on it there's no cat lays on it to break out hydrogen peroxide into water and oxygen so it'll sit there forever but if we add a certain amount of East to it what we're going to find is an when we put it in the hydrogen peroxide it's going to start breaking down that hydrogen peroxide into water and Bubbles and sub bubbles will start to build up on that can eventually it will float to the top and so we can do is we can use a stopwatch we can time how long it takes for that piece of paper to float to the top and that's going to tell us the rate of the reaction and so the more yeast we add you could imagine the faster it's going to float up to the top it so here's the results from one of the students in my class so basically we increase the concentration this is the amount of that enzyme in grams per liter and then we measured it in floats per second this kind of a weird unit Why do we measure in floats per second well it's a rate which has to be over a certain amount of time it's a basically we're timing the flow how long it takes for one of them to flow we divided by the seconds that it takes in that gives us a rate and again if it can you put it in there with no yeast what's going to be the rate will it will never ever flow so if we take one flow / infinite time that's going to have a rate of 0 but you can turn here that basically what we're going to get is a curve that looks something like that so if I were to extrapolate a little bit it's going to eventually go all the way out like that now you might yourself what were increasing the amount of yeast why doesn't it keep going linear like that well the reason why is that even though we've increase the number of enzymes we broke down so much hydrogen peroxide that it doesn't matter anymore so this should be the results that we would expect it's a basically what we're doing again to review is it we're breaking down hydrogen peroxide the water in oxygen this is the chemical formula that you need to know we're measuring that rate and we could measure that right by looking at the number of products that's what we're doing in this case measuring the amount of oxygen that's produced or we could measure a decrease in the amount of hydrogen peroxide but in this lab we only measured one thing we measured in priest in the amount of enzyme and when you taking the AP bio test he could ask you questions about other things and so what if we increase the substrate what's that going to do well if we increase the substrate going to be more of it to break down so it's going to increase right away what about pH or what about temperature will it sink about temperature for a second let's see where you take an enzyme some enzyme that's inside us let's say lactase and we were to measure it at different temperatures what would happen while we find a curve that look something like this another words is going to increase to a point like that and then it's going to decrease so temperatures an interesting one we should think about that for a second why is it increasing on this side of this optimal level well that's because substrates are moving around there moving around so molecular motion and the higher the temperature is the faster they're going to move around so they're more likely to run into an enzyme eventually drop off on this side that's because eventually that enzymes since it's a protein is going to teenager it's going to break apart now the substrate doesn't fit into it so it doesn't work and so on humans that's going to be around 37 degrees Celsius cuz that's the temperature inside our body so they're designed to work at that optimal temperature to look at bacteria that are growing and hot pause in Yellowstone Park we find it there curve is going to be way out here another words they're going to have an Optimum much closer to Boiling in other words they've evolved to that specific temperature to look at pH is going to be very similar to a curve that looks like this appear to change the pH from zero will say stop the light on I don't know 14 it's going to curve like that as well and then it's going to peek out at a specific pH it's going to be the optimum now it's not molecular motion on either side so it might look a little bit more like that it's going to be denaturing of the protein either in an acidic environment or a basic invite so now you know a little bit about enzymes how we set that up how we do that lab and soy

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Enzyme Lab - Introduction

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