Reproduction In Bacteria

Introduction

Bacteria mainly show asexual reproduction which is also determined as binary fission. The bacterium is a unicellular and microscopic organism that can also be determined as a microbe. It shows genetic transfer by recombination methods. The recombination method mainly results in the generation of non-identical daughter cells. The bacteria like microbes, or prokaryotes lack true nuclei and reproduce only by asexual methods where the fusion of gametes does not take place.

Figure 1: Binary fission in Bacteria

What is a Bacterium?

Bacteria are determined as microbes that have a simpler structure of the cell like other microorganisms, containing genetic information in a single DNA loop. Bacteria also have a circle of genetic material that is referred to as a plasmid instead of a nucleus. The plasmid consists of genes that provide the bacterium with various advantages and also helps them to reproduce. The genes also resist the microbes from certain antibiotics. The bacteria are mainly classified into 5 groups that can be identified through their size and shapes. The bacteria of different groups include rod-shaped bacteria (bacilli), comma-shaped (vibrio) or corkscrew (spirochete), spherical-shaped bacteria (cocci), and spiral bacteria (spirilla). Bacteria can also be found as single-cell microbes, in clusters, chains, or pairs.

Figure 2: Different Shapes of Bacteria

Bacteria are mainly found in different places like rocks, oceans, soil, and in arctic snow. The microbes can be found either in living plants or animals or in humans' bodies. In the human body, there are nearly 10 times of bacterial cells than human cells which are mainly found in the digestive system. Bacteria are naturally beneficial to animals or plants but can also be harmful if present as pathogens or parasites. Parasites or harmful pathogens cause serious illnesses or diseases when entering the body of organisms.

Reproduction in Bacteria

Binary fission is the common method through which bacteria reproduce. Binary fission highlights the mechanism where a unicellular bacterium gradually divides into two identical daughter cells. The process starts when the bacterium’s DNA is replicated in two DNAs and its cell elongates to get split into two daughter cells. One of the bacteria cells consists of identical DNA to the cells of its parent. The daughter cell of bacteria is the clone of its parent cell. The DNA exchange in bacteria takes place through processes including transformation, transduction, and conjugation.

Figure 3: Bacterial Conjugation

Bacteria like E.coli (Escherichia coli) divide every twenty minutes when they find a favourable temperature and proper rate of nutrients in their habitat. In 7 hours a bacterium can divide and produce about 2,097,152 bacteria. After an hour this number of bacteria will rise to nearly 16,777,216 colossal. The mechanism of quick generation or reproduction of pathogenic bacterium hints that when a bacterium invades an animal’s body it makes the body prone to illness faster.

Types of Reproduction in Bacteria

Bacteria reproduces through various modes. The main mode of reproduction in bacteria is binary fission which can also be determined as asexual reproduction. Bacteria can also reproduce through other asexual reproduction modes as mentioned below.

Reproduction through Conidia

The filamentous bacteria mainly show reproduction through the mode of conidia formation. Streptomyces is the bacteria that reproduce through transverse septum formation at the filament apex. The part where conidia are present gets detached from the mother cell and starts germinating to produce new bacteria.

Budding

Budding is determined as the asexual mode of reproduction through the cell of bacteria that generates a tiny bud or protrusion which gradually results in cell division at one location. The bud becomes matured and the partition of the wall separates it from its mother cell.

Cyst Formation

Reproduction in bacteria can also take place by the formation of cysts. Here, cysts are produced through the deposition of additional layers surrounding the parent cell during unfavourable conditions. The mother cells become normal again when the condition becomes favourable and starts generating extra layers. Through the metabolic process which is denoted as excystation breakdown and germination of the wall of cysts takes place. Excystation is the process that helps in the formation of a new bacterium.

Endospore Formation

Reproduction in bacteria can take place by the formation of an endospore where the bacterial cells are produced at the time of stressful conditions like starvation and desiccation. The bacteria consist of a core and a central protoplast including DNA, enzymes, ribosome, t-RNA, and other essential nutrients. A bacterium like E. coli reproduces through this process.

Conclusion

Bacteria mainly reproduce through binary fission and can form endospores. Endospores are dormant structures which are usually resistant to hostile chemical and physical conditions like temperature, heat, radiation of ultraviolet rays and disinfectants. Disinfectants and other physical and chemical conditions make the process of destroying the pathogenic bacteria very difficult. The bacteria which are producing endospores are harmful pathogens that cause severe illness and disease on entering the animal's or plants' bodies. The harmful pathogens that quickly reproduce and spread diseases include Escherichia coli and Bacillus anthracis.

FAQs

Q1. How does the exchange of DNA take place in bacteria?

Ans. Bacteria mainly reproduce through the asexual mode of reproduction that can also be denoted as binary fission. In bacteria, the DNA exchange takes place through various effective processes including transformation, transduction, and conjugation.

Q2. What is binary fission?

Ans. Binary fission is the common mode through which bacteria reproduce. Binary fission is also determined as the asexual mode of reproduction where a bacterial cell divides into 2 identical daughter cells. Bacteria that show binary fission include E. coli and Salmonella.

Q3. How do bacteria die?

Ans. A proper lifespan cannot be seen in bacteria as they do not grow old technically. Bacteria that live in animal or plants body is mainly denoted as the eukaryotic cell that generates and gradually dies after a set lifespan. Bacteria mainly die due to lack of nutrients, high temperature, and presence of antibiotics.