At the present time we do not know by what biochemical mechanism TSH acts on the thyroid, but for bio-assay of the hormone there are a number of properties by which its activity may be estimated, including release of iodine from the thyroid, increase in thyroid weight, increase in mean height of the follicular cells and increase in the thyroidal uptake of Af.

Empty cells represent subshells that do not exist.

As they do not have bone marrow, red blood cells are produced in the spleen and the epigonal organ ( special tissue around the gonads, which is also thought to play a role in the immune system ).

Cancer is a disease in which damaged cells do not undergo programmed cell death.

There are, however, many cells which do not follow this organisation.

For example spermatozoa and avian red blood cells have more tightly packed chromatin than most eukaryotic cells and trypanosomatid protazoa do not condense their chromatin into visible chromosomes for mitosis.

Peter Duesberg argues that retroviruses like HIV must be harmless to survive: they do not kill cells and they do not cause cancer, he maintains.

Duesberg writes, " retroviruses do not kill cells because they depend on viable cells for the replication of their RNA from viral DNA integrated into cellular DNA.

Since the valves of the heart do not receive any dedicated blood supply, defensive immune mechanisms ( such as white blood cells ) cannot directly reach the valves via the bloodstream.

On one hand they act as immunodepressors, and protect the embryo from the immune system of the mother and on the other hand viral fusion proteins cause the formation of the placental syncytium in order to limit the exchange of migratory cells between the developing embryo and the body of the mother, where an epithelium won't do because certain blood cells are specialized to be able to insert themselves between adjacent epithelial cells.

Flowering plants do not produce flagellate cells, but ferns, mosses, green algae, some gymnosperms and other closely related plants do.

Likewise, most fungi do not produce cells with flagellae, but the primitive fungal chytrids do.

The many blind people who do entrain to the 24-hour light / dark cycle have eyes with functioning retinas including operative non-visual light-sensitive cells.

Also, molecular nanotechnology might permit weapons of mass destruction that could self-replicate, as viruses and cancer cells do when attacking the human body.

The ability of cells to do this has been proposed to arise from differential cell adhesion by Malcolm Steinberg through his Differential Adhesion Hypothesis.

These two cells are identical and do not differ in any way from the original parent cell.

Some cell types, such as plant cells, do not contain MTOCs.

MPLS recognizes that small ATM cells are not needed in the core of modern networks, since modern optical networks () are so fast ( at 40 Gbit / s and beyond ) that even full-length 1500 byte packets do not incur significant real-time queuing delays ( the need to reduce such delays — e. g., to support voice traffic — was the motivation for the cell nature of ATM ).

4-Both cells synthesize a complementary strand to produce a double stranded circular plasmid and also reproduce pili ; both cells are now viable donors.

Y. pestis can reproduce inside cells, so even if phagocytosed, they can still survive.

Much research has focused on the use of adenoviruses that cannot reproduce, or reproduce only to a limited extent, within the patient to ensure safety via the avoidance of cytolytic destruction of noncancerous cells infected with the vector.

However, new studies focus on adenoviruses that can be permitted to reproduce, and destroy cancerous cells in the process, since the adenoviruses ' ability to infect normal cells is substantially impaired, potentially resulting in a far more effective treatment.

They lack membrane-bound organelles, and can function and reproduce as individual cells, but often aggregate in multicellular colonies.

4-Both cells recircularize their plasmids, synthesize second strands, and reproduce pili ; both cells are now viable donors.

Bacteria divide asexually via binary fission ; viruses take control of host cells to produce more viruses ; Hydras ( invertebrates of the order Hydroidea ) and yeasts are able to reproduce by budding.

Biological cells, given suitable environments, reproduce by cell division.

Biological viruses can reproduce, but only by commandeering the reproductive machinery of cells through a process of infection.

An asexual colony includes both somatic ( vegetative ) cells, which do not reproduce, and gonidia near the posterior, which produce new colonies through repeated division.

Some yeasts, including Schizosaccharomyces pombe, reproduce by fission instead of budding, thereby creating two identically sized daughter cells.

In 1898, Martinus Beijerinck independently replicated Ivanovsky's filtration experiments and then showed that the infectious agent was able to reproduce and multiply in the host cells of the tobacco plant.

4-Both cells recircularize their plasmids, synthesize second strands, and reproduce pili ; both cells are now viable donors.

Many lichens reproduce asexually, either by vegetative reproduction or through the dispersal of diaspores containing algal and fungal cells.

True memory effect is specific to sintered-plate nickel-cadmium cells, and is exceedingly difficult to reproduce, especially in lower ampere-hour cells.

By contrast, gametes are cells that fuse during sexual reproduction, for organisms that reproduce sexually ; Germ cells are cells that give rise to gametes ; Stem cells are cells that can divide through mitosis and differentiate into diverse specialized cell types.

The earliest known Christian monastic communities ( see Monasticism ) consisted of groups of cells or huts collected about a common center, which was usually the house of some hermit or anchorite famous for holiness or singular asceticism, but without any attempt at orderly arrangement.

The removal of dying cells by phagocytes occurs in an orderly manner without eliciting an inflammatory response.

Using these inhibitors it was discovered that cells can die while displaying a morphology similar to apoptosis without caspase activation.

According to bundle theory, an object consists of its properties and nothing more: thus neither can there be an object without properties nor can one even conceive of such an object ; for example, bundle theory claims that thinking of an apple compels one also to think of its color, its shape, the fact that it is a kind of fruit, its cells, its taste, or at least one other of its properties.

In January 2007, she and her colleagues published an article in the Proceedings of the National Academy of Science and reported that they have found a virus-like particle ( but without finding nucleic acids so far ) in less than 10 % of the cells a scrapie-infected cell line and in a mouse cell line infected by a human CJD agent.

Typically, eukaryotic cells ( cells with nuclei ) have large linear chromosomes and prokaryotic cells ( cells without defined nuclei ) have smaller circular chromosomes, although there are many exceptions to this rule.

Chromatin is only found in eukaryotic cells: prokaryotic cells have a very different organization of their DNA which is referred to as a genophore ( a chromosome without chromatin ).

In addition, some drugs that modulate tumor cell behaviour without directly attacking those cells may be used.

In cells without a nucleus ( prokaryotic ), the cell cycle occurs a process termed binary fission.

This protective function of p53 is disabled in most cancer cells, allowing them to multiply without check.

In this way, the laser light can pass through the system without harming healthy tissue, and only diseased cells, where the nanoparticles reside, get hot and are killed.

Decrease of hemoglobin, with or without an absolute decrease of red blood cells, leads to symptoms of anemia.

A modern application is the use of relatively large lenses to concentrate solar energy on relatively small photovoltaic cells, harvesting more energy without the need to use larger and more expensive cells.

ADE technology is a very gentle process, and it can be used to transfer proteins, high molecular weight DNA and live cells without damage or loss of viability.

Microfluidic fuel cells can use laminar flow to separate the fuel and its oxidant to control the interaction of the two fluids without a physical barrier as would be required in conventional fuel cells.

In all plants and in many protists meiosis results in the formation of spores: haploid cells that can divide vegetatively without undergoing fertilization.

Cessation of dosing with morphine creates the prototypical opioid withdrawal syndrome, which, unlike that of barbiturates, benzodiazepines, alcohol, or sedative-hypnotics, is not fatal by itself in neurologically healthy patients without heart or lung problems ; it is in theory self-limiting in length and overall impact in that a rapid increase in metabolism and other bodily processes takes place, including shedding and replacement of the cells of many organs.

The silver impregnation stains are an extremely useful method for neuroanatomical investigations because, for reasons unknown, it stains a very small percentage of cells in a tissue, so one is able to see the complete micro structure of individual neurons without much overlap from other cells in the densely packed brain.