Every living organism falls into two distinct groups: eukaryotes or prokaryotes. The cellular structure of these organisms determines which group an organism belongs to. In this guide, we’ll learn about the brief outline of prokaryotes and eukaryotes. Also, you’ll read the main differences between the two cell types.
Key Structures of Prokaryotic Cells
Prokaryotes are unicellular organisms that lack membrane-bound structures, notably the nucleus. Prokaryotic cells are small, simple cells, measuring around 0.1-5 μm in diameter. While prokaryotic cells don’t have membrane-bound structures, the latter doesn’t have cellular regions. The DNA bundles in the prokaryotic cells together in a region is called the nucleoid. The main structures of prokaryotic cells are:-
- Nucleoid – A central region of the cells containing DNA.
- Ribosome: This structure in a cell performs protein synthesis.
- Cell wall: It provides structure and protection from the outer environment.
- Cell membrane: Each prokaryote has a cell membrane, also known as the plasma membrane, that separates the cell from its outer environment.
- Capsule: It is the layer of carbohydrate that covers the bacteria’s cell wall. Another function of this layer is to help bacteria in attaching to the surfaces.
- Fimbriae: These are thin, hair-like structures that help with cellular attachment.
- Pili: These are rod-shaped structures involving multiple roles, such as attachment and DNA transfer.
- Flagella: These are thin, tail-like structures that assist in movement.
Examples of prokaryotes
Bacteria and Archaea
Key Structures of Eukaryotic Cells
Eukaryotes are organisms whose cells have a nucleus and other organelles enclosed within a plasma membrane. Organelles are internal structures performing a variety of functions such as energy production and protein synthesis. Eukaryotic cells are large (around 10-100 μm ) and complex structures. There are eukaryotes, which are multicellular organisms, while others are single-cell eukaryotes.
- Nucleus: The nucleus stores the genetic information in the chromatin form.
- Nucleolus: Nucleolus is found inside the nucleus. It is the part of eukaryotic cells where ribosomal RNA is produced.
- Plasma membrane – The plasma membrane is a phospholipid bilayer that surrounds the cell and the organelles in it.
- Cytoskeleton – Also known as the cell membrane, provides structure, allows for cell movement, and involves cell division.
- Ribosomes – This part of the cell is responsible for protein synthesis.
- Mitochondria – Also known as the powerhouse of the cell, these are responsible for energy production.
- Cytoplasm – It is the region of the cell between the nuclear envelope and the plasma membrane.
- Other important structures are cytosol, endoplasmic reticulum, and vesicles/vacuoles.
Examples of eukaryotes
Animals, plants, fungi, algae, and protozoans are all eukaryotes.
Differences Between Eukaryotic and Prokaryotic
The two have some similarities in common:-
- DNA
- Plasma membrane
- Cytoplasm
- Ribosomes
Differences between eukaryotes and prokaryotes are as follows:-
1). Eukaryotes
2). Prokaryotes
Nucleus
Absent
Present
Membrane-bound organelles
Absent
Present
Cell structure
Unicellular
Mostly multicellular; some unicellular
Cell size
Smaller (0.1-5 μm)
Larger (10-100 μm)
Complexity
Simpler
More complex
DNA Form
Circular
Linear
Examples
Bacteria, archaea
Animals, plants, fungi, protists
If you need help with your biology assignment, seek instant online assignment help from us. We’re available 24*7 to help you. Chat with us now!
