 Let's quickly summarize mitochondrias and plastids. Let's start with mitochondrias. They are called the powerhouse of ourselves and they look somewhat like this. You can see that there are two membranes. We have the outer membrane which is usually porous and then there is this inner membrane which is highly folded and the reason it's folded so that there is more surface area but this is the place inside the inner membrane where your digested food, the food that you eat that is converted into energy and that energy is released in the form of ATP and so that ATP is generated inside the mitochondria and that ATP is the energy that your body uses. Everywhere, wherever your body is using energy it's in the form of ATP and this is the reason why mitochondria is called the powerhouse. Without the mitochondria, the food that you eat will not be converted into ATP and you wouldn't have any energy. Mitochondria's are super important. They're found in the cells of both animals and plants. But now let's go to plastids. Plastids are found only in plants and algae. But what exactly are they? Well, they are of different types and they have different functions. Plastids comes in usually you can differentiate into two kinds. You have something called the leukoplasts. These are colorless and you have something called the chromoplasts which have colors and you can see chromostands for colors. Now, leukoplasts are mainly used for storage. Storage of fats, proteins, lipids, basically storage of nutrients. Chromoplasts and on the other hand well their main job is to give colors. So they are responsible for producing a lot of colorful pigments. Now, one specific kind of chromoplast which you might be familiar with is the chloroplast. Chloroplast is the one that has the green pigment. So you kind of see how it is, right? So chromoplasts can be of different pigments and they might have different colors but the one that has the green pigment is what we call the chloroplast. And the reason that's important is because not only is it green but it's also responsible for photosynthesis, right? Chloroplasts are the one that do photosynthesis. And so let's look at its structure now. So again, you can see chloroplasts has two membranes. It has the outer membrane and then there is this inner membrane. And if you go inside the inner membrane you'll find the whole region is filled with some kind of a fluid which we call the stroma. This coin-like structure stacked is not the stroma, okay? Stroma is the fluid that you can't see. It fills up the inner membrane. And then finally, if you go into that coin-like structure you will find molecules of chlorophyll. And it's these chlorophyll that has the color green that has the green pigment. And they're also responsible for trapping the energy of the sunlight and helping us make food via photosynthesis.