Difference Between Bacteria and Amoeba (original) (raw)
Last Updated : 23 Jul, 2025
**Bacteria and Amoeba both are unicellular organisms but they belong to different kingdoms and differ in terms of their cellular structure, locomotion, etc. Bacteria are single-celled prokaryotic organisms with rigid cell walls, that lack a nucleus and membrane-bound organelles. Amoeba on the other hand are eukaryotic protists with a flexible cell membrane, a nucleus, and pseudopodia for locomotion. In this article, we will study the differences between bacteria and amoeba and in brief about bacteria and amoeba.
Table of Content
- Difference Between Bacteria and Amoeba
- What is Bacteria?
- What is Amoeba?
- Conclusion - Difference between Bacteria and Amoeba
- FAQs on Bacteria and Amoeba
Difference Between Bacteria and Amoeba
The differences between bacteria and amoeba are as follows:
| **Characteristic | **Bacteria | **Amoeba |
|---|---|---|
| **Kingdom | Monera | Portista |
| **Cell Type | Prokaryotic | Eukaryotic |
| **Shape | Bacteria are extremely small | Amoeba have no definite shape |
| **Nucleus | Lack a true nucleus | Have a true nucleus |
| **Genetic Material | Single circular **DNA | Linear DNA in the nucleus |
| **Membrane-Bound Organelles | Absent | Present (e.g., mitochondria, endoplasmic reticulum) |
| **Cell Wall | Present in many species | Lacks a rigid cell wall, may have a flexible cell membrane |
| **Locomotion | Typically by flagella or pili | Typically by pseudopodia (temporary cytoplasmic extensions) |
| **Reproduction | Binary fission (asexual) | Binary fission and sexual reproduction (asexual and sexual) |
| **Size | Generally smaller (micrometers) | Generally larger (micrometers) |
| **Examples | Escherichia coli, Bacillus | Amoeba proteus, Entamoeba histolytica |
What is Bacteria?
Bacteria are unicellular organism that belong to the prokaryotic kingdom Monera. Bacteria are among the first life forms to appear on Earth. Bacteria can exist as single cells, in pairs, chains, or clusters. They are mostly free living and are found almost everywhere on the earth. Based on their shape they are classified into five types: Spherical (cocci), Rod (bacilli), Spiral (spirilla), Comma (vibrios), Corkscrew (spirochaetes). The characteristics of the bacteria are as follows:
- Bacteria are microscopic organism that range in size from 0.2-2 micrometers in diameter and 0.5-5.0 micrometers in length
- They possess rigid cell wall that is made of peptidoglycans. It gives them their shape.
- They lack organelles like mitochondria, Golgi apparatus.
- Bacteria lack true nucleus.
- Have a plasma membrane that generates energy and transports chemicals.
- Reproduce through binary fission.
- For locomotion they have whip-like flagella.
- They have a chromosome (nucleoid), ribosomes, and cytoplasm.
**Examples of Bacteria: Escherichia coli (E. coli) which is commonly found in the human intestine, Bacillus subtilis that is found in soil and used in various biotechnological applications. Some bacteria are harmful and are called pathogenic bacteria. Pathogenic bacteria can cause diseases and illnesses, such as: Cholera, Tuberculosis, Food poisoning, Strep throat, Staph infection.
Also Read: Multicellular Organism
What is Amoeba?
Amoeba is a single-celled eukaryotic microorganisms that belongs to the kingdom Protista. They have a jelly like structure and have the ability to change their shape by extending and retracting pseudopods. Amoeba can live in fresh water, salt water, wet soil, and as a parasite in animals. The characteristics of the amoeba are as follows:
- Amoeba microscopic organism that ranges in size from 1/20 mm to 0.1 mm.
- They have an irregular, asymmetrical shape and can constantly change their shape.
- They lack a rigid structure like cell wall.
- Their cytoplasm and cellular content are enclosed within a cell membrane.
- Amoeba uses pseudopods finger-like extensions of the cell membrane and cytoplasm that are used for movement and to surround and engulf food particles. This process is known as phagocytosis.
- They contain nucleus with an enclosed DNA.
- Amoeba reproduces asexually by binary fission, where it divides into two identical daughter cells.
- Amoebas are primarily heterotrophic in their mode of nutrition.
- Amoeba has a contractile vacuole that helps regulate water balance by collecting and expelling excess water from the cell.
**Examples of Amoeba: Amoeba proteus which is commonly used in laboratory, Brain-eating amoeba, Entamoeba histolytica which is a parasitic amoeba that can cause amoebic dysentery in humans.
Also Read: Nutrition in Amoeba with Diagram and its Process
Conclusion - Difference between Bacteria and Amoeba
In conclusion bacteria and amoeba represent two different categories of microorganism that differ in their cellular structure, reproduction, locomotion, etc. Bacteria are prokaryotic microorganisms that lack a true nucleus and undergoes binary fission. Amoebas, on the other hand, are eukaryotic organisms with a true nucleus, uses pseudopodia for movement and phagocytosis. Both play vital roles in ecosystems, with bacteria carrying out nutrient cycling across diverse environments, and amoebas have ability to adapt to different environment and are used in laboratories and in scientific researches.
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