haploid cells - is one in which the core contains single set of chromosomes.This mainly gametes - i.e. cells intended for reproduction.Also, have a haploid set of chromosomes, most prokaryotic organisms.Somatic cells of eukaryotes (all except sex) - diploid plants may be polyploid.
structure of prokaryotic cells
Prokaryotes are organisms consisting of a single cell in which there is no core.These are only bacteria.Most of them have a single set of chromosomes.
structure of eukaryotic cells is different from the fact that it lacks some of the organelles.For example, they do not have mitochondria, lysosomes, Golgi apparatus, vacuole, endoplasmic reticulum.However, as eukaryotic haploid cell plasma membrane in prokaryotes has consisting of proteins and phospholipids;ribosomes, which are involved in the production of proteins;cell wall, which in most cases is constructed from murein.Also in the structure of such a cell may be present capsule composed of substances such as proteins and glucose.Their chromosomes float freely in the cytoplasm, the nucleus or are not protected by any other structure.Most often, the hereditary material of the bacteria represented by only one chromosome, which contain information about the proteins that have to be produced by the cell.The method of reproduction of organisms - a simple division of the haploid cells.This allows them to promptly significantly increase their numbers.
eukaryotic cells having single set of chromosomes
have this kind of organism haploid nuclei contain cells called gametes.They may be quite different from the physical.Reproduction of haploid cells are sex, and the new body can start to develop only at the confluence of two gametes, synthesized by different individuals of the same species.
formed by the merger of two haploid cell called a zygote, it already has a double set of chromosomes.Although the sex of somatic cells differ from diploid, they may still have some organelles inherent eukaryotes.
animal gametes
sex cells of organisms belonging to the kingdom, called sperm and egg.First produced in the body of the male, the second - female.The eggs are produced in the ovaries and sperm - in the testicles.And those and others - specialized haploid cells, which have different functions.
Structure eggs
female germ cells have a much larger size than the male.They are fixed.Their main task - to provide a zygote initially nutrients needed for division.The egg consists of a cytoplasmic membrane, a gelatinous shell, polar body and nucleus, which contains chromosomes that carry genetic information.Also, in its present structure of the cortical granules that contain enzymes that prevents other sperm into the cell after fertilization, or could be formed polyploid the zygote (a triple and a set of chromosomes), which would entail all sorts of mutations.
egg bird egg can also be considered, but it contains much more nutrients to be enough for the full development of the embryo.Female germ cells of mammals contains many organic chemicals, as in the later stages of the development of the embryo through the placenta, he gets all the necessary from the mother's body.
In the case of birds this does not happen, so the entire supply of nutrients must be present in the original egg.The egg has a more complex structure.On top of the yolk sac and the protein shell is covered with a shell that plays a protective function, as in the present structure of the airbag, which is necessary for the fetus of oxygen.
structure of sperm
It is also haploid cells intended for breeding.Its main function is the preservation and transmission of paternal genetic material.This haploid cell the mobile has a much smaller size than the egg, due to the fact it does not contain nutrients.
Sperm consists of several parts: the tail, the head and the intermediate division between them.The tail (flagellum) is composed of microtubules - structures built out of proteins.Thanks to him, the sperm can move towards its goal - the egg, which he must fertilize.
intermediate section between the head and tail contains mitochondria, which are arranged helically around the middle part of the flagellum, and a pair of centrioles lying perpendicularly to each other.
first - it organelles that produce energy, which is necessary for the movement of gametes.The sperm head is the core of which has a haploid set of chromosomes (23 in humans).On the outside of this part of the male reproductive cells is autosome.In fact, it is slightly modified, enlarged lysosome.It contains enzymes that are needed to sperm could dissolve the outer shell of the egg and fertilize it.After the male gamete fuses with the female, the zygote is formed, which has a diploid set of chromosomes (46 in humans).She has the ability to share, because it is formed and the fetus.
haploid plant cells
Organisms of the "kingdom" produced similar germ cells.Women, too, are called eggs, and men - sperm.The first is in a pestle, and the second - on the stamen, pollen.If you get it on the pistil fertilization occurs, and then formed the fruit with seeds inside.
In lower plants (spore) - mosses, ferns - the alternation of generations.One reproduce asexually (disputes), and the other - sexually.The first is called the sporophyte, and the second - gametophyte.In sporophyte fern plant is presented with large sheets, while the gametophyte - small green structure in the shape of a heart on it and the sex cells are formed.
