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Binary Fission is a type of asexual reproduction wherein an organism divides into two, each part carrying one copy of genetic material. This process takes place with the division and duplication of the parent’s genetic matter into two parts. Moreover, here each daughter cell receives one copy of its parent DNA. Let’s understand the process of binary fission in detail and discuss some important questions related to it.
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Key Terms: Binary fission, asexual reproduction, prokaryotic and eukaryotic cells.
The Cycle of Reproduction
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- Our planet, the Earth, consists of thousands of living species that have existed for millennia. Each and every living being, from a gigantic whale to a minuscule bacterium- all of them are carrying the same circle, rather than an order of a chain with them, i.e., birth >>> growing up >>> death. This circle or chain is called a ‘life cycle’ or ‘life span’.
- In their life span, the organisms continue the journey of their species’ existence from generation across generations through a biological process called ‘reproduction’. This reproductive process is nothing but giving birth to one’s genetic offspring. Due to the diversity of the organisms, the reproductive processes differ from one species to another.
- The whole process can be performed either by a single organism or can require the presence of two of the organisms for giving birth to the offspring of a particular species. The reproduction with a single organism is called Asexual Reproduction and the process consisting of the involvements of the two organisms to give birth to the offspring is called Sexual Reproduction.
The video below explains this:
Binary Fission Detailed Video Explanation:
Asexual Reproduction: Binary Fission
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In regard to life span, all organisms die after a certain period of time. That death that occurs can be called a ‘natural death’. However, there are some single-celled organisms that don’t go through the ‘natural death’ process because they produce their offspring by dividing into two parts. Each part carries a copy of the ‘parent’s’ genetic material. This process is an asexual method of reproduction.
This specific type of reproduction is called ‘Binary Fission’. Through the cell-dividing process, the two ‘daughter’ cells get the exact copy of the genetic matter of the ‘parent’ cell and grow rapidly into an adult form. For that reason, those two daughter cells become identical to each other and they also are being referred to as ‘clones’ for that match.
Read More:
| Related Topics to Binary Fission | ||
|---|---|---|
| Pollination by Insects | Double Fertilization in Angiosperms | Pollination |
| Asexual reproduction | Reproduction in organisms mcq | reproduction in animals |
Prokaryotic and Eukaryotic Cells
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The process of Binary Fission dates back to billions of years ago and is practiced by some of the earliest life forms on earth. There are primarily two types of organisms that practice binary fission, prokaryotes, and eukaryotes.
Prokaryotes
They are single-celled, microscopic organisms that lack a nuclear membrane as well as other organelles due to the absence of inner membranes. Prokaryotes include archaea, cyanobacteria, eubacteria, etc.
Eukaryotes
They are those organisms consisting of cell(s), where the genetic material (DNA in chromosomes) is contained within a distinct nucleus. It includes all living organisms with the exception of eubacteria and archaea. Some eukaryotes like paramecium and amoeba use binary fission as a means of reproduction.
Binary Fission happens without the spindle apparatus (the cytoskeletal structure of eukaryotic cells which gets created during the cell-division process with the purpose of detaching the sister chromatids from the daughter cells) formation in the respective cell.
Read More: What is Bacteriophage
Drawbacks of Binary Fission
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This reproduction process has a major drawback. As the daughter cells are the true copies of the parent cell, if an antibiotic works on a single cell, then it naturally will work on the other cells of the same species. But if any mutation (changes of the physiology or DNA) happens in the genes of any cell, the result cells will also be having the resistance power against that particular antibiotic.
Read More: DNA Packaging
Binary Fission in Organisms
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Unlike human cells, a bacteria has a single, circular chromosome which is devoid of a nucleus. But during fission, the bacteria cell needs to copy its DNA like a human cell. Though this process is speedy, it depends on the species after all.
- Firstly, the single DNA particles get doubled inside of the bacteria. That is called ‘doubling time’. This process of copying the DNA takes place, and is known as ‘the origin of replication’. The time of this ‘doubling’ process differs from species to species.
- When the first part of the DNA gets copied, the two daughter cells start getting detached from each other, taking away the rest of the chromosome along with them. These incidents can also be seen as the preparation of splitting.
- Along with the newly added chromosomes, the cells’ growth starts.
- This process of copying continues until all the parts of the chromosome are copied and the replicated enzymes also continue meeting at the far sides.
- The growth of a new cell wall begins with the mirroring of the DNA. This is the part to separate the bacterium. This process is triggered by the FtsZ protein to perform the ‘Z-ring’ formation.
- Upon the completion of the moving of the chromosomes at the dead ends of the would-be cells, cytokinesis starts occurring.
- As soon as the new cell wall (septum) is fully developed, the result of the complete splitting of the bacterium happens.
- Now with the separation, the new bacteria cells have been formed having the tightly coiled DNA, ribosome and plasmids in each of them. These are now the new born organisms.
Now as far as the speed of the FtsZ-dependent fission is concerned, we all know that mesophiles get developed between the temperature ranging from 20 degrees to 45 degrees Celsius. The ambient temperature of our body is 37 degrees Celsius. Most of the bacterias are mesophiles. For example, we can say that the bacteria E. Coli develops every 20 minutes while at 37 degrees Celsius. Now the time of this getting developed for a bacteria differs because, besides the cell division process, a bacteria also need to duplicate the DNAs to every cell. So, some other species of bacterias take a shorter or greater time span than the time E.Coli takes. Again, as an instance, some strains of Mycobacterium tuberculosis get divided every 15 to 20 hours while E. Coli divides in every 20 minutes.
NCERT Solutions of: Class 12 Biology Chapter 1 Reproduction In Organisms
If we see the other side of the spectrum, the bacteria which fall under the category of extremophiles can live in extremely rough environments like high temperature, high acidic environments, and more. As an example, Deinococcus radiodurans is an extremophile bacteria that can withstand a thousand times more radiation than a human being can. Yes, obviously it will slow down its growth process while being in a more harsh condition than a normal condition.
Read more: Structure of RNA
Types of Binary Fission
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Binary Fission can be categorized into four types:
| Irregular | Longitudinal | Transverse | Oblique |
|---|---|---|---|
| Cytokinesis happens straight to the plane of karyokinesis strictly. | Cytokinesis takes place along the longitudinal axis. | Cytokinesis happens along the transverse axis. | Cytokinesis occurs obliquely. |
| Example: Amoeba. | Example: Flagellates like Euglena. | Example: Ciliate protozoans like Paramecium. | Example: Ceratium. |
Things to Remember
- The process of binary fission is generally very fast, and its speed varies among species.
- The time required by bacteria to double the number of cells it has is called doubling time.
- The process of Binary Fission dates back to billions of years ago and is practiced by some of the earliest life forms on earth.
- There are primarily two types of organisms that practice binary fission, prokaryotes, and eukaryotes.
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Previous Years Questions
- Meiosis takes place in...[NEET 2013]
- The sexual reproduction is absent in….[NEET 1995]
- For union between stock and scion in grafting which one is the first to occur….[NEET 1990]
- A clone is ......… [KCET 2011]
- Animals which possess cleidoic eggs exhibit….[KCET 2011]
- Which among these is not a post fertilization event ?...[KCET 2016]
- Type of asexual reproduction found in Hydra is..[KEAM]
- Which of the following is having longitudinal binary fission ?….[KEAM]
- In grafting, the stock and scion should be joined….
- The mode of asexual reproduction in Euglena is….[CUCET 2010]
- Isogamy is found in...[CUCET 2010]
- In these plants artificial vegetative reproduction is possible through….[GUJCET 2006]
- Apomixis in plant means development of a plant… [BHU UET 2008]
- Which one of the following plants reproduces vegetatively by epiphyllous buds?
Sample Questions
Ques. What are the benefits of Binary Fission? (2 marks)
Ans. Binary fission can have multiple benefits -
- Simple and fast process because of the participation of one organism only.
- This process allows the bacteria to grow epidemically (nearly 20 minutes of generation time while being in an optional condition for a bacteria).
Ques. What is the ‘lost identity’ in binary fission? (2 marks)
Ans. In Binary Fission, after karyokinesis(nuclear division) and cytokinesis(cell division), nothing is left for the parent cell. Its identity is literally lost. The newborn daughter cells take the position of the parent cell by growing up rapidly.
Ques. What is the difference between binary fission and fragmentation? (2 marks)
Ans. Binary fission occurs when a parent cell breaks into two identical daughter cells. But according to the fragmentation theory, the parent cell breaks into different parts or fragments which develop into a new organism.
Ques. Can viruses multiply through Binary Fission? (2 marks)
Ans. No, viruses can’t get multiplied using binary fission because, unlike bacteria, viruses don’t have the necessary organelles to reproduce their components. For that, it needs a victim’s cell.
Ques. What is Binary fission in plants? (2 marks)
Ans. The term ‘asexual reproduction is used as far as animal reproduction is concerned, while the term ‘vegetative reproduction is used in plants’ reproduction. The small saplings birthing from the ‘buds’ or ‘eyes’ of a potato can be the best example of Binary Fission in plants. This process is completely asexual because two parents do not participate to complete the whole task.
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