- Plasma membrane
The plasma membrane is like the skin of the cell. It is selectively permeable. This means that it decides what molecules can enter the cell and what molecules can leave it. It is made up mostly of protein molecules, which listen to the needs of the cell and can transport molecules across the membrane.
The cytoplasm is the liquid that fills the inside of the cell and transports all the molecules and structures that exist within it. The cytoplasm also acts as an incubator for all the chemical reactions that take place inside the cell, including the creation of protein.
Ribosomes are the structures within the cell that create protein molecules. There are two types of ribosomes: free ribosomes, which live in the cytoplasm and produce a protein that will function within it and membrane-bound ribosomes, which live in the membrane and produce proteins that will leave the cell.
The nucleus is located in the middle of the cell and shelters the cell’s DNA. The DNA is the equivalent of the instruction booklet for the cell and teaches it how to function. The nucleus is separated from the rest of the cell by the nuclear envelope and allows molecules to come in and out through nuclear pores.
- Endomembrane system
The endomembrane system acts as a birthplace and transport system for proteins and lipids inside the cell. It is especially important in cells that create specialized molecules, which need to be shipped to different parts of the cell quickly and efficiently.
Mitochondria are part of the process that takes energy from food and turns it into another form of energy called ATP. They have two membranes; the outer membrane, which creates a wall between the mitochondria and the rest of the cell and the inner membrane, which is the area for energy extraction.
Chloroplasts exist within the cells of plants and algae. They are the molecules, which create food through photosynthesis, a process where plants extract energy from the sun. Chloroplasts also contain inner and outer membranes, which keeps their processes separate from the rest of the cell.
The cytoskeleton is made up of protein molecules, which supports the structure of the cell. It also acts as a road for molecules who are traveling from one part of the cell to another This is the protein that is triggered every time a muscle in the body is moved.
- Cell walls
Cell walls are the extra layer of protection cells use on top of the plasma membrane. The walls are made up of three layers of proteins and carbohydrates and can help strengthen individual cells as well as form connections with other cells.
- Bacterial flagella
Bacterial flagella are part of a protein that helps move the cell forward. They take on different forms depending on the cell they are in. In prokaryotic cells, they resemble motors on a boat, whereas in eukaryotic cells, they move like fish tails.