Reproductive cells

Haploid A single set of chromosomes (in humans the 23 chromosomes from either father or mother or the single set of chromosomes in their reproductive cells) (see also diploid). 

Cycads pollination by insects may be one of the earliest forms of insect-pollination. Like conifers, cycads bear their reproductive cells in cones rather than flowers. Individual cycad plants are either male or female, male plants having pollen cones and female plants, seed cones. Fertilization requires transfer of pollen grains from pollen cones to seed cones. The role of insects in this process has received attention in a cycad commonly known as the cardboard palm (Zamia furfuracea). This is a handsome horticultural plant with... 

Human cells normally contain 23 pairs of chromosomes, for a total of 46 chromosomes in each cell. A change in the number of chromosomes leads to a chromosomal disorder. These changes can occur during the formation of reproductive cells (eggs and sperm) or in early fetal development. A gain or loss of chromosomes from the normal 46 is called aneuploidy. 

Some chromosomal conditions are caused by changes in the number of chromosomes. These changes are not inherited, but occur as random events during the formation of reproductive cells (eggs and sperm). An error in cell division called nondisjunction results in reproductive cells with an abnormal number of chromosomes. For example, a reproductive cell may accidentally gain or lose one copy of a chromosome. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra or missing chromosome in each of the body s cells. 

Changes in chromosome structure can also cause chromosomal disorders. Some changes in chromosome structure can be inherited, while others occur as random accidents during the formation of reproductive cells or in early fetal development. Because the inheritance of these changes can be complex, people concerned about this type of chromosomal abnormality may want to talk with a genetics professional. 

Germ Cells The reproductive cells in multicellular organisms. [NIH]... 

Germline mutation A gene change in the body s reproductive cells (egg or sperm) that becomes incorporated into the DNA of every cell in the body of offspring germline mutations are passed on from parents to offspring. Also called hereditary mutation. [NIH]... 

Cells can be divided into germ cells and somatic cells. Germ cells are reproductive cells, for example, ova or sperm. Germ cells contain genetic characteristics that are passed on to the next generation. Somatic cells do not contribute their genes to future generations they are the tissue cells such as nerve cells and muscle cells. 

Telomerase is an enzyme in eukaryotes used to maintain the telomeres. It contains a short RNA template complementary to the DNA telomere sequence, as well as telomerase reverse transcriptase activity (hTRT). Telomerase is thus able to replace telomere sequences that would otherwise be lost during replication. Normally telomerase activity is present only in embryonic cells, germ (reproductive) cells, and stem cells, but not in somatic cells. 

Somatic cells—All cells in the body, except the germ (reproductive) cells, that can divide to produce more cells like itself. 

Genotype The genetic constitution of the individual the characterization of the genes, [nih] Germ Cells The reproductive cells in multicellular organisms, [nih]... 

Pollen consists of reproductive cells released by plants (and sometimes carried by insects) at certain times of the year. Individual species of plant are identifiable by the grains of pollen they generate. Klaus Oeggl of Innsbruck University, James H. Dickson at the University of Glasgow in Scotland, and their colleagues have studied pollen samples obtained from Otzi s digestive tract. Some of this pollen may have been eaten intentionally, but Otzi probably swallowed most of it accidentally, either in the course of eating a meal or by inhalation. 

The effects of diepoxybutane on male reproductive cells were investigated by flow cytometric and histological description of testicular cell populations and alterations of chromatin packaging. Male B6C3F mice were treated with a single intraperitoneal... 

Somahc Cell One of the cells of the body of an individual which becomes differentiated and compose the tissues, organs, and parts of that individual, as opposed to the reproductive cells. 

Auxospore A form of reproductive cell in diatoms usually resulting from the union of two diatom cells. 

Free-radical-induced reproductive cell death is the basis of radiotherapy, and it is obvious that the main problem of this approach to fight cancer is to target the ionizing radiation to the tumor in order to prevent damage to healthy tissue. This is a most difficult if not impossible task. Radiation modifiers that sensitize the tumor cells and protect healthy tissue are considered for improving treatment regimes in radiotherapy, and the underlying mechanistic principles are addressed. 

It has been found that the effects of radiation on some vital tissues (bone marrow, spleen, blood and reproduction cells) are seen more quickly than on other tissues. Because these tissues grow faster than others, any type of damage in the cells can be easily and quickly transferred into new cells. All cells can be affected by this chain reaction. This can result in tumors, which explains the carcinogenic effect of radiation. 

After mutation in reproductive cells, the changes caused by radiation are transferred to new generations. 

Gosh, R.I. (1985). Energy Metabolism in Reproductive Cells and Embryos of Fish (In Russian). Naukova Dumka, Kiev, 148 pp. 

Evaluate the function of human and macaque granulosa, trophoblast and endometrial cells, and macaque embryos in response to 2,3,7,8-TCDD while being cultured in vitro, and the cellular mechanisms by which primate reproductive cells sustain toxic damage... 

Gamete A reproductive cell such as ovule or pollen. Female and male gametes unite to form a single cell called the zygote, which, through division, generates an embryo and ultimately a progeny individual. 

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