1. Synthesis, Digestion and Storage
Nucleus
Endoplasmic Reticulum
Golgi Apparatus
vesicle

2. Eukaryotes vs. Prokaryotes
Eukaryotic cells are larger and much more complex than prokaryotic cells. While some organelles are found in both, prokaryotes do NOT have a nucleus or any other membrane-bound organelles.

3. The Nucleus
The nucleus contains the genetic material of the cell in the form of DNA. This DNA is packaged into large structures known as chromosomes. The genetic code found in the DNA is the instructions for making the primary product of the cell: proteins.
Nucleus

4. The Nucleus
In all cells, the genetic code is copied, and these copies are sent to the “workers” as the instructions to make proteins. In eukaryotic cells, this means that the information must be carried out of the nucleus.

5. Ribosomes
Ribosomes are the workers that read the genetic code and use the information to synthesize proteins. Ribosomes can be found in the “factory” of the cell, and they also float freely through the cytoplasm.

6. Endoplasmic Reticulum
Ribosomes
Nucleus
Endoplasmic Reticulum
Golgi Apparatus
vesicle
Ribosomes are very important to ALL cells since every cell needs proteins made from its DNA. This means they are found in BOTH prokaryotes and eukaryotes.
In eukaryotic cells, many ribosomes are found in the rough endoplasmic reticulum. The ribosomes are what make the rough ER look bumpy.

7. Endoplasmic Reticulum
Nucleus
Endoplasmic Reticulum
Golgi Apparatus
vesicle
Endoplasmic Reticulum
The endoplasmic reticulum is the factory where many molecules are made. The rough endoplasmic reticulum is where proteins are synthesized. Inside of the smooth endoplasmic reticulum is where new lipids, like fat, are synthesized.
Smooth ER
Rough ER

8. Endoplasmic Reticulum
The endoplasmic reticulum also has another important function. Because it is a vast network of tubes inside the cell, it acts like veins and arteries distributing the new products to where they belong.
Smooth ER
Rough ER

9. Lipogenesis
When cells have more glucose than they need, they can use the energy to synthesize fatty acid molecules which are used to create triglycerides (fats) in a process called lipogenesis. This places the energy into lipids which store it more efficiently than glucose.

10. Endoplasmic Reticulum
Nucleus
Endoplasmic Reticulum
Golgi Apparatus
vesicle
Vesicles
Sometimes proteins and other products must be sent out from of the ER to another organelle or to the outside of the cell. When this is the case, they are packaged inside of small organelles known as vesicles. These vesicles are like packages of proteins that can be mailed to anywhere in the cell.
Inside
Outside

11. Vesicles
Vesicles are made when a small piece of membrane is wrapped around the smaller molecules during a process known as endocytosis. This creates a membrane-bound bubble that keeps the contents together as they travel through the cell.
Inside
Outside

12. Golgi Apparatus
In many cases, vesicles are used to transport proteins from the endoplasmic reticulum to one of the cell’s Golgi bodies. It is inside the Golgi that proteins are modified. This often means that sugars or fats are connected to the protein.

13. Watch the short video over protein modification in the Golgi.

14. Lysosomes
Lysosomes are special vesicles which have been filled with digestive enzymes. Enzymes are proteins that direct a chemical reaction, and digestive enzymes are designed to break apart larger molecules into small pieces.
Digestion

15. Vacuoles
Vacuoles are membrane-bound organelles which serve as storage for food and water. Vacuoles can even store harmful wastes to isolate them from the rest of the cell.

16. Eukaryotes vs. Prokaryotes
Even though prokaryotes do NOT have a nucleus or other membrane-bound organelles, they do have some features common to all cells. This includes the genetic material and ribosomes needed for protein production.