A plasmid DNA is a small circular piece of DNA that can independently replicate without the host’s chromosomal DNA.
It is found in bacteria and exists naturally in eukaryotes like plants and yeast and can also be found in archaea.
Some of the functional benefits of plasmid DNA to its host include degradative functions, resistance to antibiotics and virulence.
Natural plasmid DNA has an origin of replication and a gene such as an antibiotic resistance gene. On the other hand, artificial plasmid DNA used in laboratories are designed to introduce foreign DNA into another cell. The latter kind of plasmid DNA consists of an origin of replication, cloning site and selection marker.
Scientists or bioengineers find plasmid DNA as a great tool as it is easily modifiable and has the ability to self-replicate within a cell that makes it easier to study and experiment.
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Chromosomal DNA is a DNA molecule having all of the genetic information in the genome of an organism.
Most of the eukaryotic chromosomal DNA consists of packaging proteins and chaperone proteins which bind to the DNA molecule and condense it to prevent tangling and becoming an unorganized structure.
An important function of chromosomal DNA is to carry genetic information which is the functional unit of heredity. As we know, a gene is a segment of DNA that consists of instructions to make a particular protein or related proteins, and this gene is carried by the chromosomes. Chromosomes contain many genes and are present within the cell nucleus and mitochondria.
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In the above tabular chart, we discussed the difference between plasmid and chromosomal DNA, now we shall see the existing similarities between the two.
Both plasmid DNA and chromosomal DNA are present in bacterial cells.
Both chromosomal DNA and plasmid DNA contain genes and are composed of DeoxyriboNucleic Acid (DNA).
Both are highly significant in their own terms.
1. Distinguish Between Plasmid DNA and Chromosomal DNA.
Ans. Plasmid DNA and chromosomal DNA, both, contain genetic material, however many differences exist between the two. The former kind is present only in bacterial cells whereas the other is present in bacterial cells as well as eukaryotic cells. Plasmid DNA is called extrachromosomal DNA and its genetic material is not too vital for hereditary purpose, whereas the latter has a great importance in carrying genetic information from one generation to another. Plasmid DNA is used as vectors in biotechnological studies and has importance in molecular biology. It also provides resistance from pesticides, insecticides and herbicides to the bacterial cells. Plasmid DNA are self replicative whereas the chromosomal DNA uses the genome for replication.
2. What are the Shapes of Plasmid DNA and Chromosomal DNA?
Ans. Plasmid DNA is linear in shape whereas chromosomal DNA can be linear or circular in shape. Naturally, plasmid DNA is present as a tightly supercoiled circle to allow itself to fit inside the cell. Chromosomal DNA is often observed as X-shaped structures.