Binary Fission: Prokaryotic, Asexual, Reproduction, Definition, Steps & Examples

Binary fission is the most common asexual type of reproduction observed largely in prokaryotic organisms such as bacteria and certain protozoans. This topic is part of the Class 12 Biology chapter, Reproduction in Organisms. Understanding the concept of binary fission is important as it is one of the most important topics of biology that comes in many entrance exams like NEET, nursing exams, etc.

This Story also Contains

1. What is Binary Fission?
2. Types of Binary Fission
3. Difference Between Binary Fission and Multiple Fission
4. Binary Fission Mechanism
5. Binary Fission in Different Organisms
6. Advantages and Disadvantages of Binary Fission
7. Binary Fission and Evolution
8. Recommended Video on Binary Fission

Binary fission involves a single parent cell that divides into two genetically identical daughter cells. Each of the daughter cells inherits a copy of its parent's genetic material. More aspects about binary fission, types of binary fission, differences between binary and multiple fission, along with advantages and disadvantages of binary fission, are given in this article.

What is Binary Fission?

Binary fission refers to asexual reproduction in which one parent organism produces two identical daughter cells. It is common amongst prokaryotes, some eukaryotes, such as protozoa and certain algae. The process is very rapid under conditions that are favourable for multiplication.

Some of the general features of binary fission include the duplication of genetic material, cell elongation, and finally division into two new cells. There is no exchange or recombination of genetic material through binary fission, unlike in sexual reproduction; hence, the offspring will be identical to the parent.

The primary difference between binary fission and sexual reproduction is that binary fission has a low degree of diversity in its genes in comparison. Sexual reproduction combines the genetic materials from two parents; hence, genetically varied offspring are there to adapt well to changing environments. Binary fission produces clones, thus having the advantage in stable conditions, but possibly at a disadvantage if the environment changes.

Also Read:

• MCQ Practice on Binary Fission

• Asexual Reproduction in Animals

• Sporulation

Types of Binary Fission

Binary fission may appear in different forms depending on the nature of the organism and the method of division. There can be different forms of binary fission depending upon the need and conditions. For example, Amoeboid Binary fission, Transverse binary fission, etc. Here are some forms of Binary Fission:

Amoeboid Binary Fission

• It involves the division of the nucleus, followed by the division of the cytoplasm.

• This form of binary fission is generally used by the amoeba.

• The process begins with the elongation of the cell accompanied by the mitotic division of the nucleus.

• The cytoplasm constricts in the middle leading to the formation of two daughter cells.

• Example: Amoeba proteus.

Binary Fission in Bacteria

• Bacteria replicate their DNA before the cell divides.

• The cell elongates and the DNA molecules move to opposite poles.

• A septum forms in the middle of the cell, dividing it into two.

• The cell splits into two identical daughter cells.

• Example: Escherichia coli (E. coli).

Longitudinal Binary Fission

• The cell divides along its longitudinal axis.

• Common in flagellates.

• Example: Euglena.

Transverse Binary Fission

• The cell divides along its transverse axis.

• Common in ciliates.

• Example: Paramecium.

Multiple Fission

• Division of the nucleus several times before the division of a cell.

• Several daughter cells are produced from one parent cell.

• Important in parasitic protozoa such as Plasmodium.

Difference Between Binary Fission and Multiple Fission

As discussed above, binary fission involves the production of two identical daughter cells; on the other hand, multiple fission gives rise to the formation of many identical cells that possess the genetic material of their parent. Apart from the number of daughter cells, there are a lot of aspects in which these both types of fission differs. The table below indicates the main difference between binary and multiple fission:

Binary Fission Mechanism

Binary fission involves some basic mechanisms using which the formation of the daughter cell occurs. There are three major steps involved in binary fission: initiation, elongation, and separation. These steps are responsible for the success of reproductive attempts.

Initiation

• Replication of DNA and two copies of the exact same genetic material were made.

• The helical ends of each copy attach to areas on the cell membrane.

Elongation

• The cell grows and elongates.

• Chromosomes move to opposite ends of the cell, ensuring each daughter cell will receive a copy.

Separation

• A septum forms, beginning the division of the cell.

• The cell membrane pinches inward, splitting the cell into two daughter cells.

• The new cells are identical to the parent cell.

Binary Fission in Different Organisms

Binary fission is the process that occurs in many organisms with different mechanisms, some involve the use of enzymes while others by following self-replication techniques. All these techniques result in a successful reproduction and continuation of life. Binary fission varies across different types of organisms.

Prokaryotes

• Bacteria (E. coli): DNA replication followed by cell division.

• Archaeabacteria: A binary fission method identical to that of bacteria, but using unique enzymes and mechanisms.

Eukaryotes

• Protozoa (Amoeba, Paramecium): Binary fission is complicated, including mitosis.

• Algae (Chlamydomonas): A binary fission process that, although different, is similar in concept to protozoa.

Mitochondria and Chloroplasts

• Mitochondria and Chloroplast are semi-autonomous organelles that can replicate themselves within eukaryotic cells in a binary fission-like process, due to their prokaryotic ancestry.

Advantages and Disadvantages of Binary Fission

Binary fission has advantages and disadvantages of its own. From allowing for a rapid population growth to not helping with genetic diversity. Understanding both advantages and disadvantages is equally important to know the process of Binary fission in a more conscious manner. The advantages and disadvantages of binary fission are given below:

Advantages

• A rapid method of reproduction that allows a fast tempo of population increase.

• Does not require a mate, which simplifies the reproductive process.

• The daughter organisms are genetically identical, allowing successful traits to be passed on.

Disadvantages

• Low genetic diversity makes populations more vulnerable to changes in the environment.

• Inability to fight against diseases and other environmental factors.

Binary Fission and Evolution

Binary fission in evolutionary biology is important because this method of reproduction can increase the population to a very large extent in a very short period of time. However, binary fission does not have the same meritorious features of high population diversity seen in sexual reproduction. However, errors during DNA replication can lead to variations that would contribute to evolution over a period of time.

Other Useful Resources:

Recommended Video on Binary Fission