What is the Difference Between Genophore and Plasmid

The main difference between genophore and plasmid is that genophore is the genetic material of prokaryotes, whereas plasmid is a small circular DNA molecule separated from the prokaryotic chromosome.

Genophores and plasmids are two types of DNA molecules that occur inside prokaryotic cells. The main function of this DNA is to store information for an organism to develop, survive, and reproduce.

Key Areas Covered

1. What is Genophore
     – Definition, Structure, Function
2. What is Plasmid
     – Definition, Structure, Function
3. Similarities Between Genophore and Plasmid
     – Outline of Common Features
4. Difference Between Genophore and Plasmid
     – Comparison of Key Differences

Key Terms

Genophore, Plasmid

What is Genophore

Genophore is the DNA of prokaryotes commonly referred to as the prokaryotic chromosome. Generally, it is circular in most prokaryotes, while it is linear in some prokaryotes. It also contains the prokaryotic chromosome that is circular and surrounded by chromatin fiber. Generally, the size of the prokaryotic chromosome is much larger in comparison to the dimensions of the prokaryotic cell. Therefore, it requires compacting through the mechanisms of supercoiling in order to fit into the cell. The size of the prokaryotic chromosome is around 5 Mb. In addition, it is a double-stranded DNA molecule encoding genetic information in a haploid form.

Figure 1: E. coli Nucleoid

Furthermore, nucleoid refers to the genophore of the model organism, E. coli which is a Gram-negative bacterium. It contains highly compact DNA that is also in a highly organized form. There are two essential aspects of nucleoid formation in E. coli. They include the condensation of a large amount of DNA into a small cellular space while functionally organizing the genome of the prokaryote in the three-dimensional space. In the meanwhile, the main function of the chromosome in the nucleoid is to store information required for the development and reproduction of the prokaryote.       

What is Plasmid

A plasmid is an extrachromosomal genetic element mainly occurring in prokaryotes. It can replicate independently of the genome. Usually, a plasmid is a small, circular, double-stranded DNA molecule. The size of a plasmid can vary from 1-200 kbp. In addition, the number of identical plasmids can range from 1-20 per prokaryotic cell. However, small plasmids occur in copy numbers as higher as 50. Apart from that, different types of plasmids can occur inside the same cell. Plasmids are also capable of replicating independently inside the prokaryotic cell.

Figure 2: Plasmids

Moreover, there are two types of plasmids according to the ability of conjugation. Generally, conjugative plasmids contain a set of transfer or TRA genes, promoting sexual conjugation. Non-conjugative plasmids, on the other hand, are unable to initiate conjugation. Moreover, there are five classes of plasmids classified by function. They include F-plasmids, which are capable of conjugation, R-plasmids containing genes for antibiotic resistance, Col plasmids, containing genes for bacteriocins and proteins and kill other bacteria, degenerative plasmids, enabling the digestion of unusual substances, and virulence plasmids, which turn bacteria into pathogens. Furthermore, the main function of plasmids is to store information for the survival of bacteria in different environmental conditions.  

Similarities Between Genophore and Plasmid

• Genophores and plasmids are two types of DNA that occur inside prokaryotic cells.
• Both are circular, double-stranded DNA.
• They do not contain histones.
• The main function of this DNA is to store information needed by cells to develop, survive, and reproduce.
• Both types of DNA are inherited from generation to generation.
• They replicate independently.
• Moreover, they contain a single open reading frame.

Difference Between Genophore and Plasmid

Definition

Genopore refers to genetic behavior and correlated DNA fibrils of bacteria, while plasmid DNA refers to a small circular DNA molecule found in bacteria and some other microscopic organisms.

Significance

Genophore is the chromosomal DNA of prokaryotes, while plasmid is extrachromosomal DNA, excluding the genomic DNA.

Structure

Moreover, a genophore is a prokaryotic chromosome surrounded by chromatin fibers, while a plasmid is a small, circular DNA.

Size

The size of the chromosomal DNA inside the genophore is less than 5 Mb, while the size of the plasmid is around 200 kbp.

Number

Genopore contains a single circular DNA molecule per prokaryotic cell, while a prokaryotic cell contains 1-20 copies of plasmid DNA.

Types

Genophore contains a single type of chromosomal DNA, while prokaryotic cell contains multiple plasmids.

Function

In addition, the genophore stores the genetic information for the development and reproduction of the prokaryote, while plasmids contain information for the survival of prokaryotes in different environmental conditions.

Transfer

The DNA in the genophore transfers during cell division while the plasmid can transfer through horizontal gene transfer.

Importance

Genophore contains a chromosome important for studying the genetic information of prokaryotes, while plasmid is important in recombinant DNA technology.

Conclusion                                                                                                         

In brief, genophores and plasmids are two types of DNA that occur inside prokaryotic cells. The main function of this DNA is to store information for the development, survival, and reproduction of the organism. Normally, the genophore is the prokaryotic chromosomal DNA surrounded by chromatin fibers. It also contains a single chromosome that transfers during cell division. In addition, the main function of the genophore is to store genetic information required for the development and reproduction of prokaryotes. In comparison, the plasmid is a small, circular DNA molecule, excluding the genetic material of prokaryotes. Usually, it occurs in numbers, and the main function of the plasmid is to store information for the survival of prokaryotes in different environmental conditions. Therefore, the transfer of plasmids occurs through horizontal gene transfer. The main difference between genophore and plasmid is the type and the structure of each DNA.                                                         

References:                

1. Genophore. Encyclopedia Biotiny. 
2. Plasmid. Genome.gov. 

Image Courtesy:

1. “Subhash nucleoid 01” By Subhash C. Verma, Zhong Qian, Sankar L. Adhya – Own work (CC BY 4.0) via Commons Wikimedia
2. “Plasmid (english)” By Spaully – Own Work (CC BY-SA 2.5) via Commons Wikimedia