On Earth, there are two major types of cells: eukaryote and prokaryote.
Eukaryote cells are more complex in structure and function than prokaryote cells.
In this tutorial, we’ll tour the major features of a eukaryotic cell
using both an animal cell and a plant cell as examples.
Because of its large size, the nucleus is one of the most noticeable structures in the eukaryotic cell.
The nucleus is the storage site for most of the cell’s genetic information.
The dark structure inside the nucleus is the nucleolus.
This is where the components of the ribosomes are manufactured.
The endoplasmic reticulum, or ER, is a membranous network of sac like structures in the cytoplasm of the cell.
The ER is divided into two distinct types based upon structure and function.
The rough ER is studded with ribosomes, the location of protein synthesis in a cell.
The presence of the ribosomes gives this ER its “rough” appearance.
The proteins produced by the rough ER are often secreted by the cell
and carried by vesicles to the Golgi apparatus for further modification.
The smooth ER is a membrane bound organelle involved in lipid synthesis, detoxification, and carbohydrate metabolism.
It is given the name “smooth” endoplasmic reticulum because there are no ribosomes on its cytoplasmic surface.
The Golgi apparatus consists of a series of flattened sacs that resemble pancakes.
Its job is to package and distribute cellular products that are destined for a specific location within the cell or for secretion.
You can think of the Golgi apparatus as the “post office” of the cell, where packages are dropped off, and destinations are assigned.
Lysosomes, which are produced by the Golgi apparatus, are vesicles that aid in the breakdown of materials within the cell.
They may also digest worn or damaged organelles and recycle their components.
Mitochondria are the location where the stored energy found in carbohydrates is used to produce cellular energy in the form of ATP.
Mitochondria are found in both plant and animal cells.
Unique to the plant cells are the chloroplasts, the location of photosynthesis.
This is where incoming sunlight is used to convert carbon dioxide gas to carbohydrates and other compounds.
Vacuoles are specialized membrane bound structures found mostly in the cells of plants.
Vacuoles usually store substances, such as water, sugars and salts, as well as pigments and toxic molecules.
The pigments are responsible for the red, blue and green colors of flowers and some leaves.
The toxic chemicals keep the plant from being eaten by animals.
Centrioles are organelles found mainly in animal cells.
They are composed of microtubules and occur in pairs.
Centrioles function in the reorganization of microtubules during the process of cell division.
The cytoplasm contains a complex network of protein fibers called the cytoskeleton.
These fibers include microtubules, microfilaments and intermediate filaments.
Overall, the cytoskeleton plays a similar role to the bones and muscles in your body,
providing structural support, and, along with motor proteins, allowing the cell and organelles to move.
Let’s do a quick recap.
The internal structure of a eukaryotic cell is fairly complex and differs slightly between a plant cell and an animal cell.
This diagram will help you remember some of the similarities and differences.