Eukaryotes vs. Prokaryotes
Difference Between Eukaryotes And Prokaryotes
Eukaryotes are bigger because of the all intracellular structures which are rather large. The size of eukaryotic cells typically have a diameter of anywhere between 50-20 microns.
Prokaryotes are generally much smaller than eukaryotes, and the diameter of their cells is about 0.1 to 10 microns.
Eukaryotes are quite slow to divide because of their greater size and complexity. Mitosis often takes more than an hour per step, which limits the speed at which cells can divide within. There are some single-celled eukaryotes that have a generation time of about two hours if you give them the right conditions.
Prokaryotes have a simpler design and smaller size, much more capable of reproducing itself. E-coli is subject to the same conditions, the ability to share in each quarter.
All eukaryotic cells can reproduce by normal mitosis (cell division), and some more complex organisms use meiosis to sexually reproduce and create daughter cells with mixed properties from the two cells it comes from.
Prokaryotes reproduce by binary fission only. However, there is the possibility of gene transfer within and between species by transformation, transduction and conjugation.
Eukaryotes always have a cell membrane, and sometimes a cell wall.
In prokaryotes, the gram-negative bacterium has two cell membranes, with a cell wall between them. The remaining prokaryotes have a cell membrane and often cell wall too.
Many eukaryotes have no cell wall. The eukaryotes that have cell walls based on materials like cellulose, lignin or chitin.
In prokaryotes based bacteria usually their cell walls consist of peptidoglycan, tekoinsyra and lipotekoinsyra. Archean, often lack a cell wall, but when they have so often consists of pseudopeptidoglykan, polysaccharides or glycoprotein.
Eukaryotes have a nucleus that protects DNA. DNA in eukaryotes are linear, meaning that there is a linear chain with two ends. Genome is compressed using histone (a protein) to the so-called nucleosomes to save space. In some eukaryotes, there are also plasmids that contain DNA, but it is very rare in the group as a whole.
Prokaryotes have a circular DNA structure, which basically means that you have taken a linear DNA and coupled it to a ring. However, there are a few prokaryotes with linear DNA. The genomes (chromosome) in prokaryotes are not protected by a nucleus, but are free in the cell (known as super coiling). It is quite common to plasmids in prokaryotes.
Eukaryotes contain many organelles, which are present within the membrane enclosed space on the inside of the cell.
Prokaryotes relatively have fewer organelles, and they are quite poorly studied.
Eukaryotic cells have a nucleus. The core is protected by a nuclear membrane, which regulates as an in and out-passage.
Prokaryotes have that lying freely in the cell.
Mitochondria / chloroplasts
The eukaryotic cells have access to intracellular symbiotic in the form of mitochondria and chloroplasts, which handles many important functions that require energy.
Prokaryotes manage their energy all by themselves.
Eukaryotes have a fairly sophisticated protein synthesis, where they “splice” together several different variants of a protein from the same original code of DNA. This is due to the presence of introns (noncoding regions) of DNA, which is cut away from the mRNA, it is overwritten, so that you can combine the exons (coding regions) in a variety of ways depending on what the cell needs for protein.
Prokaryotes have only exons, indicating that the mRNA transcribed from DNA are exactly the mRNAs that goes to the translation.
Eukaryotes have access to a large arsenal of things you can do with the proteins after they are synthesized in the translation. One can for example add the functional groups of the protein, such as fatty acids, acetylation, alkylation, hydroxylation, jodering, and glycosylation. You can also change the amino acid sequence, for example, cleaving the protein at a specific sequence, or changing the existing amino acids.
Prokaryotes have also access to posttranslational modification, but this is fundamentally different from what the eukaryotes have. Prokaryotes, for example, are not glycosylated proteins which mean that one cannot produce many eukaryotic proteins in prokaryotes. Posttranslational modification in prokaryotes is not well explored.
Many genes can be controlled under the same promoter on the DNA. When a “start signal” is released from a promoter than many genes can be expressed simultaneously. Operant is the cluster of genes that respond to the promoter. If stimulation via promoter decreases then it results in the end of expressed genes.
Operons are poorly studied especially those that exist in the eukaryotes.
Prokaryotes regularly use operons to regulate gene expression. Examples are lac-operons responsible for energy supply in the form of glucose and lactose, and trp-operons that respond to the availability of the amino acid tryptophan (and down-regulates the enzymes that produce it when the concentration is high in the cell).