Transcription
In a previous slide, we talked about exergonic reactions. Here's an example of a diagram, an energy diagram showing an exergonic reaction. Um, and you can see on the diagram how the reactants start off with high energy, and then they go through the reaction, and the products have very low energy. So, if this is where we start, these are our reactants. Here are our products. And because the products have less energy, the energy must have gone somewhere, and it's released in the form of heat or light or sound. And this is what we call an exergonic or energy out reaction.
And here's some statements, um, that pertain to this curve, this energy curve. The reactants, which is what you start with, contain more energy than the products. This is true. All right. Um, energy is released or off during the reaction. This is also true. It has to be released because where did it go? The products have less energy, so they, the energy must have come out and gone somewhere. And then energy is not destroyed or created, it's just converted into another form. This is also true because this is the law of thermodynamics. Energy is never destroyed nor created, it's always just converted. So, all this, um, all these three statements are true.
Now, if we, um, move on. Organisms, living things like you and I, and a dog, and a tree, um, they're also able to store energy, stash energy away in the form of chemical energy, um, over time. And so, what would a reaction look like that would store energy? Because the previous example was energy being released, given off, or put out, but what happens if you wanted to store energy away? Well, in that case, our curve would look a little different. So, I'm going to draw another graph here. Um, probably going to be a bit shaky. Here's my axis. So, this is the reaction happening, and this is the amount of, of energy on this axis, getting higher and higher. So, if we're starting off with something that doesn't have very much energy, it's going to be pretty low. And we're going to put energy into the molecule and make extra bonds and store energy up. And the products are going to be a higher energy than reactants. So, here, here's our reactant, and here is our product.
So, this is an example of a reaction where energy went in, and you ended up with a product that had more energy than what you started with. Um, so, let's, let's say we started off with two kilocalories over here. We put in 10 calories of energy. Oops, that's a bad. Put in 10 calories. This is going to end up with 12 kcals because we start off with two, put in 10, ended up with a product, whatever it might be, that has 12 kilocalories. Now, this kind of a reaction is called endergonic. So, when energy goes in, we call this ender, like entrance, endergonic. All right. An endon reaction is like energy going in, where the product ends up with a higher energy level than the reactant. So, you have exergonic and endergonic. One's energy out, exit. One's energy in, entrance. All right.
So, here's one example of an andronic reaction. We'll get onto this later on in this unit, but we start off with carbon dioxide and water. Uh, and this is a very small, simple molecules. They have quite low energy, which is why they're way down here on the graph. And this is something that we can't do as humans, but this is something that plants are amazingly good at. Plants can actually sunbathe, absorb the elite from the sun, and use that elite to assemble all these CO2 and H2O molecules into a molecule of glucose. This is the process of photosynthesis. We'll get into how this happens in a couple weeks or next week. Um, but you've gone from very simple molecules that have low energy to a much bigger, complicated molecule, glucose, with all these bonds, all these bonds here, very high energy stored in all these bonds. The energy had to come from somewhere. It didn't come out of thin air. And where it came from was elite. So, here's the calories of light coming in, and they're being absorbed and being used and stored away in the glucose. So, really, that sugar molecule that was built by the plant by the process of photosynthesis has got taken El light, light energy, and stored it away as e-chemical, stored in the bonds of the glucose molecule. It's kind of a magic process. We'll get into the details of how that happens, but plants are master energy converters, um, and are able to do that, collect solar energy and turn into e-chemical by this endergonic reaction.
So, here's some more questions. The products, which is what we end up with, have more energy compared to the reactants. Is energy put in or released? Well, it's definitely put in because we had to climb the hill, we had to push them up the hill. And in this reaction, energy is converted from e-light, the solar or e-solar into e-chemical. Here's the energy of light coming in, and it's turned into these bonds up here in glucose by the mystical process of photosynthesis, which we will demystify next week. All right, that's an endergonic reaction.