[Biology Class Notes] on Difference Between Plasmid DNA and Chromosomal DNA Pdf

Characteristics/ Features

Plasmid DNA

Chromosomal DNA

Single-stranded/

Double-stranded

It is always double-stranded.

It is single-stranded or double-stranded.

Shape

It is circular in shape.

It may be linear or circular in shape.

Histone proteins

Plasmid DNA is naked without the presence of histone proteins.

It is coated with histone proteins.

Presence

Plasmids are separated from bacterial genomic DNA.

Chromosomal DNA freely floats in the cytoplasm of bacterial cells while in eukaryotic organisms, they are found inside the nucleus.

Vital genes

It doesn’t carry any vital gene which is necessary for the cells. However, plasmids contain genes that provide benefits to bacteria including antibiotic/herbicide/ pesticide resistance, drought tolerance, etc.

It carries multiple genes which are vital for cells to carry genetic information and hereditary properties. These are important for the well-being and survival of organisms.

Self-replication

It has self-replicating properties without the main genome help. 

It replicates with the genome only.

Genetic factor

It doesn’t act as a genetic factor and is often termed as extrachromosomal DNA.

Chromosomal DNA acts as a genetic factor.

Introns/Exons

Introns are absent in plasmid DNA, only exons are present.

It comprises both introns and exons. 

Size

It is smaller than chromosomal DNA.

It is larger in size as compared to the plasmid DNA. 

Quantity

Their number in a cell varied from 1-1000.

Their number varies depending upon the species. 

Transfer

It is transferred by horizontal gene transfer.

It is transferred by cell division. 

Rate of Replication

It has a higher rate of replication.

It has a comparatively lower rate of replication.

Importance

• It is important for recombinant DNA technology.

• A crucial technique used in molecular biology is the isolation of plasmid DNA which is an essential step for varied procedures like cloning, transfection, DNA sequencing, and gene therapy. Here, isolation of plasmid DNA of the highest purity is required.

• It has great importance to be used as a vector in biotechnology.

• Vital for all living beings, chromosomal DNA is essential for an inheritance, coding for proteins and genetic information for life and all processes helping in cell development and reproduction too.