cells of all living organisms have a similar structure.All of them are composed of the plasma membrane envelope around it (glycocalyx in animals or cell wall: Fungi - chitin, plants - cellulose), cytoplasm (in which are located organelles, each of which performs its functions, cell center, e.g.It participates in the division) and the core, which protects the DNA (except prokaryotes).
cell organelles
These include ribosomes, lysosomes, mitochondria, Golgi apparatus, endoplasmic reticulum and the cell center.The plant cells also contain specific organelles that are unique to them - the vacuole.They accumulate unnecessary material plastids (chromoplasts, leucoplasts, chloroplasts, in the past the process of photosynthesis).The functions of the cell center, mitochondria, ribosomes and other structures are very important.Mitochondria act as distinctive stations energy production, there is a process in which intracellular respiration.Ribosomes are responsible for the production of proteins by synthesizing them from the individual amino acids in the presence of mRNA, which contain information about the substances necessary cell.Functions are lysosomes in the degradation of chemical compounds by enzymes contained within the organelle.Golgi complex accumulates and stores certain substances.Endoplasmic reticulum is also involved in metabolism.
cell center - the structure and function
This organelle is called the centrosome.The functions of the cell center is difficult to overestimate - without this it would be impossible organelle cell division.It consists of two parts.This is similar to the cell center ribosome structure which also includes two halves.Parts of the centrosome called centrioles, each of them looks like a hollow cylinder formed from microtubules.They are perpendicular to each other.The functions of the cell center is the formation of centrioles spindle during meiosis or mitosis.
As the cell divides?
There are two main ways - meiosis and mitosis.Functions cell center manifested in both processes.And in the first and second cases, the division takes place in several stages.Allocate the following stages: prophase, metaphase, anaphase, telophase.Meiosis usually involves two consecutive cell division, while between them is called interphase.As a result of this process from the cell with a diploid set of chromosomes (double) is formed with multiple haploid (single).In the process of mitotic chromosome number does not decrease - the daughter cells also possess a diploid set.There is also a method of dividing as amitosis.In this case, the core, and then the whole cytoplasm simply divided in two.This type is not as common as the first two, it is found mainly among the simplest.Cell center in this process is not involved.
Participation cell center in the division
Prophase means preparing for the process of mitosis or meiosis, its collapse over the nuclear envelope.During metaphase cell center is disconnected into two separate centrioles.They, in turn, diverge to the opposite poles of the cell.At this stage, the chromosomes line up along the equator.Then they threaded spindle attached to the centrioles so that different chromatids of each chromosome were attached to opposite centrioles.During the metaphase chromosomes from each split into separate chromatids that centrioles the strings to the opposite poles attract.During telophase nuclear membranes are formed, and finally the cytoplasm divides forming daughter cells.
