What is a Eukaryote?

Eukaryotes are organisms composed of eukaryotic cells. Including the protozoa, fungal, plant and animal kingdoms. Eukaryotes are the collective name for all single-celled or multicellular organisms whose cells have a nucleus. It includes all animals, plants, fungi, and other organisms with complex subcellular structures surrounded by membranes. The fundamental difference between eukaryotes and prokaryotes is that the former's cells have a nucleus with a nuclear membrane as a boundary, so this type of cell is named after eukaryotes. Many eukaryotic cells also contain other organelles, such as mitochondria, chloroplasts, and Golgi.

Eukaryotes ( eukaryotes ) are a large class of organisms with nuclear membranes that can undergo mitosis, and mitochondria or chloroplasts in the cells. include

Eukaryotes are all

The direct ancestor of the most primitive eukaryote is likely to be an abnormally large prokaryote, with an endoplasmic reticulum formed from the plasma membrane in the body.

In the form of mitosis, the division of the nucleus is usually coordinated with the division of the cell. This process allows each nucleus to obtain a copy of the parent's chromosome. In most eukaryotic cells, there is another sexual reproduction process, namely meiosis. In this process, the diploid parent cell divides into a haploid through two divisions, and the amount of DNA is halved. However, meiosis itself is divided into many types.

Compared with prokaryotic cells, eukaryotic cells have a smaller surface area-to-volume ratio, so they have a slower metabolic rate and a longer cell cycle. In some multicellular organisms, some cells dedicated to metabolism increase the surface area, such as small intestinal villi.

Sexual reproduction

Eukaryotes use sexual reproduction extensively, and there is evidence that this is the original and fundamental characteristic of eukaryotes. Based on phylogenetic analysis, biologists Dax and Roger proposed that ancestors shared by eukaryotic cells perform random behaviors. A core group of genes in meiosis is found in Trichomonas vaginalis and Giardia intestine, two organisms that were previously considered asexual. In the eukaryotic cell evolution tree, the two species were separated very early, so it can be concluded that the core gene of meiosis exists in the common ancestor of all eukaryotes, and therefore this ancestor is sexual. Other studies of eukaryotic species have also revealed evidence of the reproductive cycle. For example, the parasitic protozoan Leishmania recently showed the existence of a reproductive cycle. Evidence shows that the amoeba, which was previously considered asexual, was also sexual in ancient times, and most of the asexual organisms have only recently evolved independently asexually.