What are 4 Examples of eukaryotic cells?

The eukaryotic cell is the building block of life in protozoa, fungi, plants, and animals. It represents the fundamental biological basis of the organisms belonging to the Eukarya domain.

The word “eukaryotic” is derived from the Greek eukaryon ( eu (true) + karyon(nucleus)) which means true nucleus.

Differences between prokaryotic cell and eukaryotic cell

Within the concept of cells, we know that there are two types: prokaryotic and eukaryotic. The prokaryotic cell is a simple structure, with its genetic material and its free components in the cytoplasm. In contrast, the eukaryotic cell presents more elaborate compartments and functions. In addition, many types of eukaryotic cells can form a multicellular organism.

In the eukaryotic cell, the genetic material is sheltered in an internal membranous structure, called the nucleus. From here begin the activities aimed at cell division and protein synthesis.

Structure of the eukaryotic cell

In every eukaryotic cell, three main parts can be distinguished:

1. The plasma membrane: the envelope that contains all the cellular material, besides being the means by which cells exchange information, receive nutrients and eliminate waste.
2. The core: is the center of control and regulation of cellular functions. It is made up of the nuclear envelope and the nuclear content.
3. The cytoplasm: is the aqueous-gelatinous space in which the cellular elements float and their activities develop.

Characteristics of the eukaryotic cell

The distinctive feature of all eukaryotic cells is the presence of the nucleus. However, there are other characteristics:

• They have varied forms: from spherical and cylindrical, to flat and cubic. The shape of a cell is not fixed, it depends on the medium in which it is located. For example, the cells of the epidermis, the superficial layer of the skin, are cuboidal initially and as they age they become flat.
• They have varied sizes: they can range from 10 μm to 100 μm. In order to observe these cells, a microscope is required. However, there are some cases of cells that can be observed with the naked eye, such as frog eggs (1 mm) and eggs of birds.
• They have organelles: in addition to the nucleus, eukaryotic cells contain many other types of organelles, which may include mitochondria, chloroplast, Golgi apparatus, among others. Each organelle is separated from the rest of the cell space by a membrane as if it were the rooms inside a house.
• The functions are separate: The functions that a eukaryotic cell must carry out are separated in the organelles. For example, the chloroplast is responsible for photosynthesis, the mitochondrion is responsible for cellular respiration, the Golgi apparatus is responsible for the packaging of material.
• Internal structural framework: the cytoskeleton of the eukaryotic cell is composed of filamentous proteins that give physical support to the cell and the constituents of the cytoplasm.

Why is the nucleus of the eukaryotic cell so important?

The presence of the nucleus is distinctive of the eukaryotic cell. This structure is so important because it is the place where the DNA of the cell is lodged, that is, where the genetic information is located. It is also the place where the process of synthesis of proteins begins, which are the effectors of the different cellular activities.

For the synthesis of proteins, first, the DNA is “rewritten” in a type of RNA, called a messenger. This messenger RNA leaves the nucleus towards the ribosomes, where the genetic information is transformed into protein. By separating the DNA from the rest of the cellular components, protein production is improved.

Origin of the eukaryotic cell

The origin of the eukaryotic cell is a subject of wide discussion in biology. According to fossil records, eukaryotic beings emerged 2 billion years after the prokaryotes.

Autogenic theory

According to this model, the prokaryotic cell itself evolved creating internal structures from its own plasma membrane, which then specialized in organelles, originating the eukaryotic cell

Endosymbiotic theory

Lynn Margulis (1938-2011) suggested in 1967 that the first step in the origin of eukaryotes was the need to survive in an oxygen-rich environment. Therefore, an aerobic prokaryote (the protomitochondria) was ingested by an anaerobic prokaryote. Then the first endosymbiosis was formed on Earth, by combining the DNA of both microorganisms. This theory is known as the Endosymbiotic Theory.