All animals are multicellular organisms and their basic unit is the eukaryotic cell. It differs from the prokaryotic cell, typical of the Monera kingdom organisms, mainly due to the presence of a differentiated nucleus surrounded by a nuclear membrane. Eukaryotic cells also have the capacity to form multicellular organisms and coexist with different types of cells specialized in specific functions within complex living beings. Examples of cells with different forms and functions in the members of the Animalia kingdom are the neurons of the nervous system, the leukocytes of the immune system and the ovules and sperm of the reproductive system, among many others.
Animal cells have a diameter smaller than that of plant cells and do not have a cell wall or chloroplasts. Animal cells are distinguished from plants by lack of cell wall and chloroplasts.
The nucleus of the cell is the control center of it. In short, he is responsible for dictating instructions for the proper functioning of many biological processes. It is a very important element since it harbors the deoxyribonucleic acid (DNA) that contains the genetic information that is going to be transmitted when other cells are generated.
The DNA linked to proteins forms chromatin, which, when condensed at the time of cell division, generates structures similar to threads called chromosomes.
The nucleus is an organelle since it is found in the cytoplasm. It occupies up to 10 percent of the space inside the cell and is the largest component of the cell.
It is a thin layer that surrounds the cytoplasm and separates the cell from its environment. Its main function is to protect the cell from the outside and facilitate the exchange of materials.
This membrane has pores or protein channels that communicate the interior with the external environment, thanks to which the entry of useful substances for nutrition occurs and the exit of those that are waste. It is a semipermeable membrane.
Its composition is characterized by the presence of a double layer of phospholipids with embedded proteins.
It also has a fundamental role in other important processes such as cell adhesion and cellular communication that allows the exchange of information with other cells or tissues.
-Osmosis passive and diffusion.
-Active transport.
-Endocytosis
-Exocytosis
Finally, the cell membrane helps to fix the cytoskeleton, so it is vital to maintain the shape of the cell and allow it to be part of large arrays of cells that shape the tissues.
The cytoskeleton gives the form and maintains the structure of the cell and is fundamental in the processes of endocytosis and cell division.
In prokaryotic cells, the cytoskeleton is composed of microfilaments and microtubules.
The cytoplasm is all the cellular material with the exception of the nucleus, that is, it includes all the organelles or specialized parts of the cell and the cytosol, a colorless substance of semiliquid consistency in which numerous molecules are found and carried out. some chemical reactions.
It is in the cytoplasm that most cellular activities occur, including several metabolic pathways such as glycolysis and processes such as cell division.
The cytosol is the part of the cytoplasm that is outside the organelles delimited by membranes and is equivalent to approximately 70% of the cell volume.
Endoplasmic reticulum. It is a system of channels and flattened and interconnected sacks wrapped in a membrane. The elaboration, storage and transport of some substances takes place in this organelle. It also provides internal support. Although the endoplasmic reticulum is present in most eukaryotic cells, it is not found in red blood cells or sperm. There are two types of endoplasmic reticulum, the smooth and the rough. The latter has that appearance because it has ribosomes attached to its surface. However, these ribosomes are not a structural part of the reticulum, since they freely adhere or detach from the membrane.
Ribosomes are the organelles that synthesize the vital proteins for many cellular processes. They are complex molecular machines that are found in all living cells. Its shape is spherical and are formed by ribosomal RNA and proteins. These organelles can be found in two forms: free in the cytoplasm or associated with the membranes of the rough endoplasmic reticulum and perform their function of making protein molecules by binding amino acids. However, the ribosomes follow the order specified by the messenger RNA that transfers the genetic code of the nuclear DNA to indicate the order in which the amino acids must be linked. The ribosomes have two parts, the minor subunit that is responsible for reading the RNA and the larger subunit whose function is to join the amino acids to create a peptide chain.
Mitochondria are the producers of energy in the cell. They produce it by means of the process known as cellular respiration and it is where the Adenosine Triphosphate (ATP) is made, a molecule that constitutes the main source of energy usable by the cell to perform its functions. Mitochondria synthesize ATP from glucose, fatty acids and amino acids. They do not have a defined structure since they deform easily but are usually elongated. Apart from the production of energy, mitochondria are related to the processes of cellular communication, cell differentiation and apoptosis or programmed cell death, but also have control over the cell cycle and cell growth. The number of mitochondria in a cell varies widely. For example, erythrocytes or red blood cells do not contain mitochondria but liver cells have around 2,000.
-External mitochondrial membrane.
-Internal mitochondrial membrane.
-Intermembranous space.
-Matrix.
-Crests.
It is the organelle that receives proteins and lipids from the endoplasmic reticulum and where the collection of all the substances that the cell expels to the lysosomes or through the plasma membrane is carried out. The Golgi apparatus completes the manufacture of some proteins and packages others by coating them with a membrane before being sent to its destination, "labeling" these proteins to send them to where it belongs both inside and outside the cell.
-Modification of proteins.
-Cellular secretion.
-Production of plasma membrane.
As part of the administration of traffic, the Golgi apparatus is fundamental in the secretion of substances that are expelled from the cell.
Regió cis-Golgi.
Medial region.
Trans-Golgi Region
Lysosomes are spherical vesicles that contain hydrolytic enzymes that facilitate the assimilation of substances by making them smaller. Additionally, they are responsible for eliminating waste through the digestion of unwanted substances through the cytoplasm. Lysosomes protect the cell from foreign bodies such as viruses and bacteria and digest even parts of the cell that are discarded as organelles that are replaced. These organelles contain more than 60 different enzymes that come from the Rough Endoplasmic Reticulum and serve to perform their functions of decomposing and digesting biomolecules.
They are organelles that house a large amount of enzymes necessary for various metabolic reactions that aims to dispose of toxic peroxides for the cell. Its main function is to break down long chain fatty acids. In animal cells, these acids are converted to medium-chain fatty acids before being sent to the mitochondria to be converted into carbon dioxide and water.
It is a pair of cylindrical structures coordinated and composed mainly of a protein called tubulin, which are called Centriolos. The centrioles intervenes in two processes: division and cellular locomotion (movement). They are also related to the organization of the cytoskeleton. The centrosome is only found in the animal cell.
