This video is all about what goes on under the hood of eukaryotic cells, one of the largest sub-sections of cellular life.
So what we have to do first is just remind ourselves of what it means for a cell to be eukaryotic. In general, it basically means that the cell has membrane-bound organelles. Membrane-bound organelles are like sub-compartments in the cell with different roles to fulfill in order to maintain the function and health of the cell. One issue is that some organelles are in select types of cells. So what we’ll do first is list off some organelles that are in all cells. So first we obviously have our cell membrane, and then most cells will have some form of genetic information. One of the unique qualities of eukaryotic cells is that its DNA has enclosed in a membrane-bound organelle. This organelle is the first one that we’ll talk about and is known as the nucleus. Its main purpose is acting as the control center of the cell and enveloping the genetic information. On the outside of the nucleus, we can see these holes and these are known as nuclear pores. These are used to connect to another important organelle known as the endoplasmic reticulum.
It’s very near the nucleus and the organelle looks like these layers of membranes that have a lot of surface area. The main purpose of the endoplasmic reticulum is the transportation of genetic information out of the nucleus. For example, some DNA will be occasionally transcribed into mRNA. After that, it will move out of the nucleus through the nuclear pores and into the endoplasmic reticulum. Once this is done, the mRNA will enter another organelle, which is one of the few organelles without a membrane, and it’s known as the ribosome. This makes ribosomes responsible for protein synthesis. Some of them are on the surface of the endoplasmic reticulum, and that is how they receive some mRNA.
There is actually another organelle that is very similar to the endoplasmic reticulum, with a similar shape, and function. This is known as the Golgi apparatus. It packages molecules and proteins to be used outside of the cell. In other videos, we’ll go into detail on how a protein might go to a Golgi body, and get some sort of envelope around it to be ready to be shipped out of the cell. The next organelle is one of the most well-known structures in the cell, as it’s commonly known as the powerhouse of the cell. It’s the mitochondria. The mitochondria are mostly known for being the primary source of chemical energy generation, which is where it gets the name, powerhouse of the cell. But how do they do this, and what form of chemical energy do they generate? The process is actually relatively complex and the chemical energy comes in the form of ATP, which is also known as adenosine triphosphate.
Now if this eukaryotic cell was a plant cell, like an algae cell, for example, it would have an exclusive set of organelles called chloroplasts. These organelles are responsible for photosynthesis in plants by capturing light energy and using it to convert carbon dioxide and water into oxygen and energy-rich organic compounds such as glucose. This means that chloroplasts are one of the organelles in eukaryotic cells that are only in plant cells and not animal cells.
One of the organelles that are not so well known as the mitochondria or the nucleus per se is the vacuole. In-plant cells, vacuoles can often be very large, taking up around half of the cytoplasm sometimes, but in animal cells, they are about the same size as all the other organelles. Vacuoles contain water and enzymes for the most part and have the main purpose of acting as a storage compartment for the cell. These organelles are packed with enzymes and normally help with breaking down waste products or foreign substances that aren’t supposed to be there. There are still many more organelles that will slowly be introduced when necessary but this is the general idea of what you will find in the majority of a cell’s cytoplasm. However, there are lots of things in the cytoplasm that are not organelles and serve other purposes.
So even after all of the things we’ve just learned, we’re still just scratching the surface of the complexity of the most basic unit of life. So in the next video, we’ll take a closer look at the differences between eukaryotic and prokaryotic cells, which are the two main divisions of cells. But for now, I thank you all for watching.
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