Overview of Prokaryotic Cells
- A prokaryotic cell is a cell that does not have a true nucleus.
- The nuclear structure is called a nucleoid.
- The nucleoid contains most of the cell’s genetic material and is usually a single circular molecule of DNA.
- A prokaryotic organism, such as a bacterium, is a cell that lacks a membrane- bound nucleus or membrane-bound organelles.
- The exterior of the cell usually has glycocalyx, flagellum, fimbriae, and pili.
Overview of Eukaryotic Cells
- A eukaryotic cell is larger and more complex than a prokaryotic cell and found in animals, plants, algae, fungi, and protozoa.
- Eukaryotic cell have a highly organized structure of organelles that are bound by a membrane.
- Each organelle performs a specialized function for the cell’s metabolism.
- Eukaryotic cells also contain a membranebound nucleus where the cell’s DNA is organized into chromosomes.
- Depending on the organism, a eukaryotic cell may contain flagella and cilia.
- These are used for moving the cell’s surface or for moving the entire cell.
- Flagella move the cell in a wavelike motion within its environment.
- Flagella and cilia are comprised of axoneme microtubules.
- An axoneme microtubule is a long, hollow tube made of protein called a tubulin.
Differences between Prokaryotic and Eukaryotic Cell
|Cell wall||Include peptidoglycan
|Plasma membrane||No carbohydrates
|Glycocalyx||Contain a capsule or
a slime layer
|Contained in cells that
lack a cell wall
|Flagella||Protein building blocks||Multiple microtubules|
|Cytoplasm||No cytoplasmic streaming||Contain cytoskeleton
Contain cytoplasmic streaming
Ribosomes located in
Organelles are 70S
|Nucleus||No nuclear membrane
0.2–2.0 mm in diameter
|Have a nucleus
Have a nuclear membrane
Have a nucleoli
10–100 mm in diameter
|Chromosomes||Single circular chromosome
|Multiple linear chromosomes
|Cell division||Binary fission||Mitosis|
|Sexual reproductions||No meiosis
DNA transferred in fragments