From the single bacterial cell to the trillions in humans, cells often referred to as the “building blocks of life” make up all living things. Each of these cells is a discrete structure surrounded by a cell membrane and filled with a thick solution called the cytoplasm. In human cells, most of the DNA is found in a compartment within the cell called the nucleus. It is called nuclear DNA.
In eukaryotes, the cell’s genetic material, or DNA, is contained within an organelle called the nucleus, where it is organized in long molecules called chromosomes. However, DNA is not only located in the Nucleus but also Present in the Mitochondria in Eukaryotic cells. In the case of the plant cell, one more organelle contained DNA which is chloroplasts.
Where Is DNA Located in a Eukaryotic Cell?
Eukaryotes can be unicellular or multicellular. Unlike prokaryotic cells, eukaryotic cells have a nucleus and other organelles. Eukaryotes encompass a wide range of organisms, from fungi to plants and animals.
In eukaryotic cells, most of the DNA is found in the nucleus (although some DNA is also found in other organelles, such as the mitochondria and chloroplasts in plants). Nuclear DNA is organized into linear molecules called chromosomes
The size and number of chromosomes vary significantly between species. For example, the fruit fly (Drosophila) has 4 chromosomes, while a toad (Xenopus laevis) has 18 chromosomes. In humans, most cells typically have 46 chromosomes or 23 pairs. Exceptions to this are mature red blood cells, which contain no DNA, and sperm and egg cells, which have 23 unpaired chromosomes.
Chromosomes are made up of a single molecule of DNA wrapped around a small, spool-like protein called histone. The wrapping of DNA around a histone is important, otherwise, most DNA molecules would not fit into cells.
In humans, for example, if you unrolled and stretched out the DNA molecules from end to end, the total length of DNA in a cell would be over six feet (or about two meters). But this amount of DNA has to fit into the nucleus, which is only five to ten microns in diameter. This means that fitting all of the DNA into the nucleus of a human cell is equivalent to packing 24 miles (about 40 km) of very thin thread into a tennis ball!
What Is the Function of DNA in a Cell?
The key function of DNA in a cell is to store the genetic information that enables an organism to develop, function, and reproduce. The information encoded in DNA can be passed from one generation to the next, serving as a biological manual that makes each organism unique.
In order to follow the instructions in DNA, a cell must first copy a gene into a form of RNA called messenger RNA (mRNA). This process is called transcription. In many cases, the information contained in DNA must be translated into a protein in order for the instructions to be carried out since proteins do most of the work in cells and perform a variety of critical functions