Differences Between Plasmid and Chromosomal Dna in Bacteria

DIFFERENCES BETWEEN PLASMID AND CHROMOSOMAL DNA IN BACTERIA.

Eukaryotes have two or more chromosomes, prokaryotes such as bacteria possess a single chromosome composed of double-stranded DNA in a loop. DNA is located in the nucleoid of the cell and is not associated with protein A plasmid is an extra-chromosomal DNA molecule separate from the chromosomal DNA which is capable of replicating independently of the chromosomal DNA. Plasmids usually occur naturally in bacteria.
A chromosome is an organized structure of DNA and protein that is found in cells. A chromosome is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions. 1. Plasmids are circular and double stranded. 2. Plasmids have much less base pairs than chromosomes 3. Plasmids are rarely organized by chaperone proteins 4. Plasmids are easily transferred
- Plasmids are considered transferable genetic elements, or "replicons", capable of autonomous replication within a suitable host. Plasmids can be removed from the host cell in the process of curing. Curing may occur spontaneously or may be induced by treatments such as ultraviolet light. Certain plasmids, called episomes, may be integrated into the bacterial chromosome. Others contain genes for certain types of pili and are able to transfer copies of themselves to other bacteria. Such plasmids are referred to as conjugative plasmids. 5. Plasmids usually contain non-essential genes
- Plasmids have relatively few genes (fewer than 30). The genetic information of the plasmid is usually not essential to survival of the host bacteria.
6. Plasmids function can be lost or gained without harming the organis
GENOMIC DNA VS PLASMID IN BACTERIA.

1. Genomic DNA contains genes necessary

for the survival and normal function of each organism. These genes encode proteins such as

enzymes, receptors, and structural proteins. The size of genomic DNA varies, depending on

the species. The more complex the species, the more genomic DNA it usually has.

2. Genomic DNA differs

among species not only in size, but also in shape. Most organisms, such as humans, have

linear genomic DNA. Bacterial genomic DNA is circular.

3. Genomic DNA, most bacteria contain multiple copies of a smaller circular

DNA called plasmid DNA also known as a plasmid or vector. In few bacteria,

Plasmid DNA is linear.

4. Bacteria are exposed to extreme conditions. In nature, microbes often

compete against each other for nutrients. They suppress the growth of other species, including

bacteria, by secreting antibiotics. Most bacteria have also evolved defense

mechanisms against these same antibiotics. Genes that protect bacteria against antibiotics are

located on plasmids. These genes are called antibiotic-resistance genes, and they encode

enzymes that degrade antibiotics. Plasmids may also carry genes that enable bacteria to

survive in the presence of toxic heavy metals.

5. Another difference between genomic and plasmid DNA is that plasmids can be

exchanged horizontally from one bacterial cell to another. This transfer occurs between two

individual bacterial cells and does not involve cell division. Some plasmids may even

be transferred between different bacterial species.

6. Genomic DNA, however, is only passed on from a mother cell to daughter cells during cell

division. This means that a trait carried by plasmid DNA, such as antibiotic resistance, can

quickly be spread within a bacterial population.

5. Plasmid DNA exists within a bacterial cell in multiple copies, and its replication is

independent of the replication of genomic DNA. High-copy plasmids occur within a single

bacterial cell in over 20 copies. Low-copy plasmids are present within a cell in less than 20

copies. Definitions of high- and low-copy plasmids may vary depending on the source of

information. 7. Both genomic and plasmid DNA are double-stranded.