The eukaryotic meaning or Eukaryotes are species that carry a nucleus contained within a nuclear envelope. They belong to the Eukarya Domain. One of the domains of life in the three-domain structure is the domain Eukaryota; Bacteria and Archaea are the other two domains. The Eukaryote is now commonly believed to have originated in the Archaea in or as the twin of the now developed Asgard Archaea.
Eukaryotes constitute a small percentage of the total number of living species, but their aggregate global biomass is predicted to have been equal to that of prokaryotes due to their comparatively much larger scale. Approximately 2.1-1.6 billion years ago, during the Proterozoic eon, eukaryotes appeared, presumably as flagellated phagotrophs.
Single-celled eukaryotes are the one that has established mitochondria, nucleus, and other organelles and are also termed as unicellular eukaryotes. Phytoplankton, or algae, and zooplankton or protozoa are the examples. single-celled eukaryotes emerged somewhere around billions of years ago.
The below-given picture represents the Eukaryotic cell diagram:
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Eukaryotic cells are the one that contains the organelles which are membrane-such, such as Golgi apparatus and mitochondria, and chloroplasts can be observed in algae and plants; while primitive organelles can be found in prokaryotes.
In addition to being unicellular, eukaryotes can also be multicellular and have several types of cells that form various tissue types; prokaryotes are usually unicellular in contrast. Insects, animals and fungi are the most common eukaryotes. Protists can be another example of eukaryotes.
Eukaryotic organisms are observed to undergo the process of reproduction both by asexually and sexually. The asexual reproduction is carried out via meiosis wherein, two rounds of cell division are followed by DNA replication to produce four haploid daughter cells. The sexual reproduction is carried out via mitosis wherein a single cell tends to undergo division to form two genetically identical cells.
These function as sex cells also called gametes. There is only one set of chromosomes for each gamete and each is made up of the appropriate pair of parental chromosomes which was a result of genetic recombination during the process of meiosis.
The eukaryotic cell structure is mainly comprised of below mentioned eukaryotic cell parts:
The plasma membrane divides the cell from the world outside.
It contains unique inserted proteins that assist in the movement of substances inside and outside of the cell.
A cell wall can be defined as a rigid structure that is found on the exterior of the cell of the plant. However, in animal cells, it is absent.
It helps in providing the cell with structure and assists in cell-to-cell interaction.
It is a defensive layer that is responsible for protecting the cell from any attacks by pathogens or any sort of injury.
The cell wall is observed to be majorly composed of Cellulose, hemicellulose, pectin, protein, etc.
These can also be termed as the "powerhouse of cells" because they generate energy.
It is made up of an external membrane and an internal membrane. It divides the inner membrane into folds which are called cristae.
They assist in the control of the metabolism of cells.
It can be seen as a network of tiny, tubular structures separating the surface of the cell into two components: luminal and extraluminal.
There are two types of Endoplasmic Reticulum:
There are ribosomes in Rough Endoplasmic Reticulum.
Smooth Endoplasmic Reticulum which does not have any ribosomes and is thus smooth.
The nucleus is made up of nucleoplasm which apparently contains DNA and proteins.
Two membranes, the outer membrane and the inner membrane, together form the nuclear envelope. These two membranes are permeable to molecules, ions, and the substance of RNA.
Within the nucleus, ribosome development also takes place.
It is mainly composed of flat structures called cisternae which are disc-shaped.
They lack in sieve cells of plants and red blood cells of humans.
Golgi apparatus are arranged close to the nucleus, parallel and concentrically.
It is an excellent spot for glycoprotein and glycolipid formation.
In plants, animals, fungi, protozoa, and other complex species, eukaryotic cells are exclusively present. The eukaryotes examples of eukaryotic organisms are described below:
Plant cells: The cell wall is composed of cellulose, which gives the plant support. cIt has a wide vacuole that retains the turgor pressure. The photosynthesis is carried out in the plant cells as they contain chloroplasts.
Animal cells: They have a cell membrane and thus lack a cell wall. And that is because animals have shapes that differ. They have the potential for phagocytosis and pinocytosis is to be carried out.
Protozoa: Protozoans are species which are unicellular. For locomotion, some protozoa have cilia. The cell receives protection from a thin layer called a pellicle.
Fungal cells: The cell wall of the fungal cells is found to be made up of Chitin. Many fungi contain openings, called septa, that permit the passage of cytoplasm and organelles through them.
1. Which Organelle Can Be Said to Be the Cell Powerhouse or Powerhouse of the Cell?
Ans. Mitochondria are found to be small organelles present inside the cells and are involved in generating energy from food. This extraction of energy is carried out by a process called cellular respiration. And so mitochondria are called to be the powerhouses of the cell.
2. Why are Lysosomes Termed as the Suicidal Bags?
Ans. Lysosomes are sphere-shaped sacs found to be filled with some hydrolytic enzymes which are involved in the digestion of lipids, protein, nucleic acids, and carbohydrates. They are also involved in the breaking down of all the unwanted materials and thus they are termed as ' the suicidal bags.'