A cell is a structure made up of several organelles, which are surrounded by a membrane. The organelles are responsible for a number of functions within a cell, including the production of energy, excretion and digestion. Enzymes are also present inside cells, helping with the renewal of cells.
Nucleus
The nucleus of an animal cell is the centre of the cell’s information. It stores the genetic code, which determines the amino acid sequence of proteins. The nucleus also performs transcription, which creates different kinds of RNA from DNA. The resulting molecules are then translated in the cytoplasm, where they serve as templates for protein synthesis.
The nucleus is a structure made up of several nuclear bodies, which are composed of unique RNA molecules and proteins. They also contain specific parts of chromosomes. The nucleolus is most famous for its assembly of ribosomes, which are responsible for the translation of messenger RNA. The nuclear envelope is formed of an outer ring and a nuclear pore. The nucleus is functionally connected to the cytoplasm through these pores.
Besides the nucleus, animal cells also contain the cytoplasm. The cytoplasm is a fluid-filled space within the cell. It contains dissolved nutrients, transports material within the cell, and helps break down waste products. The nucleus is the most important organelle in the cell, as it controls most of the cell’s activity. The nucleus also contains chromosomes, which contain genetic information.
The nucleus is the “brain” of the cell. It contains the genetic information and the instructions to produce proteins. It also contains DNA and histone proteins.
Mitochondria
Mitochondria are highly dynamic organelles in the cell. Their dynamics have been categorized into two major categories: morphological dynamics and motility dynamics. These two factors are interrelated in determining mitochondrial function and regulation. The mitochondrial cytoskeleton contains enzymes that perform a variety of functions including respiration.
The inner membrane of the mitochondrion contains five proteins known as the respiratory chain. These proteins transfer energy in the form of electrons from the outer membrane to the inner membrane. The energy is then converted into ATP. This process is called chemiosmosis.
Mitochondria are unique among cell organelles because they are surrounded by two membranes and contain their own genome. In addition, mitochondria can divide independently from the host cell. Because their replication is not tightly coupled with cell division, this feature is the result of evolutionary adaptation. The number of mitochondria increases in cells with increased energy demands.
Mitochondria are found inside animal cells. These organelles contain four types of fatty acids and a central protein responsible for ATP synthesis. The inner membrane is also composed of many folds known as cristae. These folds increase the surface area of the inner membrane, allowing more ATP to be produced.
The mitochondria produce energy and break down food into simpler forms. This energy is then used by the cell. As a result, mitochondria are considered to be the “powerhouse” of the cell. If their functions are reduced, the body becomes less functional. This can cause weak muscles, easy bone breaks, and even organ failure.
Lysosomes
Lysosomes are internal organelles that play a key role in digestion. They contain over 50 different enzymes and function as a waste disposal system in the cell. They have a pH between 4.5.0, which makes them acidic, making them an ideal location for the breakdown of biological polymers. Lysosomes may also play a role in metabolic homeostasis and nutrient sensing.
Lysosomes are found in all animal cells. They are particularly important for white blood cells, which must digest much more material than other cells to fight foreign invaders. They are also involved in disorders such as Tay-Sachs disease, which is caused by a genetic defect and causes mental retardation and death during early childhood. Another disorder that involves lysosome enzyme escape is arthritis inflammation.
The morphology of lysosomes varies among different cell types. In platelets, the lysosomes are spherical, whereas in melanocytes, they are rugby-ball-shaped. They are also found in endothelial cells and in pulmonary alveolar type II cells. Despite the differences between the two types of lysosomes, they are similar in composition.
Lysosomes were first discovered by Belgian biologist Christian Rene de Duve in the mid-twentieth century. He was studying the metabolism of carbohydrates in liver cells, and noticed that when cells were damaged in a centrifuge, they released more enzymes. His findings led him to hypothesize that these enzymes were encased in a membrane-bound organelle. He subsequently estimated the size of the lysosome and identified it through electron microscopy images.
Centrosome
Centrosomes play a critical role in animal cell division. Without them, the cell cannot divide. The centrosome is required for bipolar spindle assembly and cytokinesis. In some cells, centrosomes are redundant, but the bipolar spindle is still present.
The name centrosome derives from the work of biologist Theodor Boveri, who hypothesized that the centrosome could duplicate into two. He observed that the daughter centrosomes took on an ellipsoidal shape during the duplication process. However, both centrosomes grew back into spherical shapes before they separated.
The centrosome contains a large number of genes, including those responsible for regulating cell growth and development. These genes play important roles in the formation of the centrioles, as well as in microtubule stability and length regulation. The centrosome is absent in many types of animals, including protists and fungi. It is also absent in the Planaria flatworm and female oocytes. The absence of a centrosome also results in the absence of the centrioles in a mouse embryo.
Although centrosomes are not necessary for cell division in mammalian cells, their presence improves the efficiency of mitotic spindle arrangement. In humans, centrosomes that are defective can increase chromosomal instability, increasing the risk of cancer. They may also enhance cancer cells’ ability to spread through the bloodstream.
Flagella
The flagella in an animal cell are a type of motile cellular projection. These appendages are similar to those found on prokaryotic cells, but they differ significantly in length and function. The flagella, in fact, are longer and less numerous than cilia, but they both function to move cells and other materials. The two types of flagella are also related structurally, although they differ in length and beat patterns.
In animals, flagella are recognized intracellularly by receptors belonging to the NLR family. This recognition occurs through antibody recognition of the D3 domain of flagellin. These receptors are involved in triggering innate immunity in the cells. However, this recognition may not be specific to each species.
Flagella are a characteristic feature of prokaryotic cells. They are associated with the protozoan group of organisms, including algae, mosses, and slime molds. The movement of flagella causes the water currents that are needed to propel the organism. Most bacteria are motile, and their flagella help them breathe.
Flagella are also important for adhesion to plant cells. Flagella bind to phospholipids and algae polysaccharides, making them suitable for intercalating into plant plasma membranes. Flagella-mediated adherence may also involve other factors.
