Collegedunia Team Content Curator
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The most significant differences between DNA in chromosomes and DNA in plasmids are the replication sites and mobility of the genetic material. Plasmid genes are easier to transfer between bacteria than chromosomal DNA.
Between bacteria and other types of cells, there are a number of fascinating differences. Plasmids in bacteria are one of them. Separate from bacterial chromosomes, these tiny, rubber-band-like loops of DNA exist. Plasmids, as far as we know, are only found in bacteria and not in other living things. In modern biotechnology, they also play a significant role.
Key Terms: Plasmid DNA, Chromosomal DNA, DNA, Gene Therapy, Cell Division, Gene, Plasmids, Prokaryotic Cells, Bacteria
Plasmid DNA
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Plasmid DNA is a tiny, circular, extrachromosomal DNA found in bacteria that replicates autonomously and is used in genetic engineering and recombinant DNA technologies." Self-replication is unique in that it can be used in a variety of molecular genetic studies, including gene therapy, gene transfer, and recombinant DNA technologies.
Most bacteria have a single circular chromosome, with a few exceptions. This chromosome contains the majority of a bacterium's genetic material, and it is only duplicated or copied when the cell splits. The bacterium, on the other hand, could have one or several plasmids. Some plasmids only replicate when the cell divides, while others are duplicated at different periods.
Plasmid DNA
It's possible that a cell contains many copies of the same plasmid, especially if the plasmid replicates independently of cell division. When a cell divides, a bigger number of plasmids consumes more energy because DNA replication costs energy. However, if these plasmids give a benefit such as antibiotic resistance, the benefits they provide may more than compensate for the burden.
- For the purpose of researching the function or expression of a gene, a gene of interest or a therapeutic gene is integrated into plasmid DNA and delivered to the target cell.
- Understanding what plasmid DNA is and how scientists use it is critical for a molecular geneticist.
- Plasmid DNA, which is generated artificially, is a critical component in the synthesis of GMO plants, medicinal medicines, and proteins.
Read More: Genetically Modified Organisms (GMOs)
Functions of Plasmid DNA
- Plasmid DNA plays an important role in the organism's survival.
- It kills other host cells by generating poisonous proteins, and it defends its own cells by growing resistant to the invading organism or killing it.
- In some severe conditions, the plasmid also aids in the replication of bacterial DNA.
| Relevant Concepts | |
|---|---|
| Gene Regulation | Genetics |
| Genetic Disorders | Genetic Drift |
Chromosomal DNA
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Chromosomal DNA is a DNA molecule that contains all of an organism's genetic information. The carrying of the gene, which is the functional unit of heredity, is a crucial function of chromosomal DNA. A gene, as we all know, is a fragment of DNA that contains instructions for making a certain protein or related proteins, and it is carried by chromosomes. Many genes are found on chromosomes, which are found in the nucleus and mitochondria of cells.
- The genomic DNA found in prokaryotic and eukaryotic organisms is referred to as chromosomal DNA.
- The majority of eukaryotic chromosomal DNA is made up of packaging and chaperone proteins that bind to the DNA molecule and condense it to keep it from tangling and creating an unstructured structure.
Chromosomal DNA
Read More: Chromosomal Theory of Inheritance
Difference between Plasmid DNA and Chromosomal DNA
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The difference between Plasmid DNA and Chromosomal DNA is as follows:
| Plasmid DNA | Chromosomal DNA |
|---|---|
| It is circular in shape. | It is linear or circular in shape. |
| Found only in prokaryotic cells. | Found in both prokaryotic and eukaryotic cells. |
| Helps in recombinant DNA technology. | Helps in the reading of genetic information |
| The rate of replication is high. | The rate of replication is comparatively lower. |
| Double-stranded. | Single-stranded or double-stranded. |
Things to Remember
- Plasmid DNA is extrachromosomal DNA that has been isolated from genomic DNA.
- It is circular in form and usually occurs inside bacterial cells.
- It has an antibiotic resistance gene for bacterial survival, which aids in the development of resistance to several natural antibiotics.
- Chromosomal DNA is a DNA molecule that contains all of the genetic information in an organism's genome.
- The majority of eukaryotic chromosomal DNA is made up of packaging and chaperone proteins, which bind to the DNA molecule and compress it to prevent it from tangling and creating an unstructured structure.
Sample Questions
Ques. What is the function of plasmid DNA? (2 Marks)
Ans. Only a few genes are carried by plasmids, which exist independently of chromosomes, the basic structures in cells that contain DNA. Plasmids can be picked up from the environment and transported between bacteria since they can self-replicate. Plasmids assist their host organism in dealing with stressful situations.
Ques. Are plasmids made up of RNA or DNA? (2 Marks)
Ans. Plasmids are usually circular DNA molecules, though linear or RNA-based plasmids do arise on occasion. They can be single or numerous copies, and they can include anything from a few dozen to several hundred genes. Plasmids can only replicate within the confines of their host cell.
Ques. What is the purpose of using plasmid as a vector? (2 Marks)
Ans. Plasmids are non-chromosomal, self-replicating, double-stranded, closed, and circular DNA molecules found in bacteria. Plasmids have enough genetic information to replicate themselves. Plasmids are utilized as vectors because when introduced into them, they can carry a foreign DNA fragment.
Ques. How many DNA strands are there in a chromosome? (2 Marks)
Ans. In a double helix, one chromosome has two DNA strands. The two DNA strands in chromosomes, on the other hand, are extremely lengthy. A single strand of DNA can be extremely short, even shorter than a tiny chromosome. Strands of DNA are formed by stringing together the four DNA bases.
Ques. Are chromosomes made up of 40% DNA? (2 Marks)
Ans. Chromosomes are made up of lengthy chromatin threads. A central core of DNA (which makes up roughly 40% of the chromosome) and packaging proteins make up this material (about 60 percent ). The DNA thread is twisted around a complex of eight proteins called histones every 200 nucleotides along its length.
Ques. What are the various properties of Plasmid DNA? (5 Marks)
Ans. Plasmid DNA has a number of characteristics that set it apart from other forms of DNA:
- Plasmid DNA is a double-stranded DNA molecule that is circular.
- It's classified as a replicon since it has a replication origin and is hence self-replicating.
- Depending on the type of plasmid, the size of the plasmid can range from a few Kelo base pairs to a few megabase pairs.
- The horizontal gene transfer through the conjugation process is one of the most essential features of plasmid DNA.
- Each bacterium inherits a plasmid, which is a self-replicating material.
- Plasmid DNA is typically 1 to 2 kb in size (used in genetic research), and because of its small size, it is simple to manufacture and manipulate for genetic engineering.
- For gene transfer and gene therapy investigations, the plasmid can be employed in a variety of different species.
Ques. Identify the difference between plasmid DNA and chromosomal DNA. (3 Marks)
Ans.
- Although both plasmid DNA and chromosomal DNA contain genetic material, there are major differences between the two. The former is found only in bacterial cells, whereas the latter is found in both bacterial and eukaryotic cells.
- Plasmid DNA is also known as extrachromosomal DNA, and its genetic material is not as important for hereditary purposes as that of chromosomal DNA, which is crucial for passing genetic information from one generation to the next.
- Plasmid DNA is a type of DNA that is employed as a vector in biotechnological research and is important in molecular biology. It also protects bacterial cells from pesticides, insecticides, and herbicides. Plasmid DNA is self-replicating, whereas chromosomal DNA replicates through the genome.
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