POLIO

Polio (also called poliomyelitis) is a contagious, historically devastating disease that was virtually eliminated from the Western hemisphere in the second half of the 20th century. Although polio has plagued humans since ancient times, its most extensive outbreak occurred in the first half of the 1900s before the vaccination created widely available in 1955.

Polio is a highly infectious disease caused by a virus. It invades the nervous system, and can cause total paralysis in a matter of hours. The virus enters the body through the mouth and multiplies in the intestine.

Cell Membrane

Cell Membrane

The cell membrane is a biological membrane that separates the interior of all cells from the outside environment. The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells.

It consists of the phospholipid bilayer with embedded proteins. Cell membranes are involved in a variety of cellular processes such as cell adhesion, ion conductivity and cell signaling and serve as the attachment surface for the extracellular glycocalyx and cell wall and intracellular cytoskeleton.

Amniocentesis

Amniocentesis (also referred to as amniotic fluid test or AFT), is a medical procedure used in prenatal diagnosis of chromosomal abnormalities and fetal infections, in which a small amount of amniotic fluid, which contains fetal tissues, is extracted from the amnion or amniotic sac surrounding a developing fetus, and the fetal DNA is examined for genetic abnormalities.

Before the start of the procedure, a local anesthetic can be given to the mother in order to relieve the pain felt during the insertion of the needle used to withdraw the fluid. After the local is in effect, a needle is usually inserted through the mother's abdominal wall, then through the wall of the uterus, and finally into the amniotic sac.

Antibody

An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen.

Each tip of the "Y" of an antibody contains a paratope (a structure analogous to a lock) that is specific for one particular epitope (similarly analogous to a key) on an antigen, allowing these two structures to bind together with precision. Using this binding mechanism, an antibody can tag a microbe or an infected cell for attack by other parts of the immune system, or can neutralize its target directly.

Vaccine

A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins.

The agent stimulates the body's immune system to recognize the agent as foreign, destroy it, and "remember" it, so that the immune system can more easily recognize and destroy any of these microorganisms that it later encounters.

Molusca

Molluscs are soft-bodied animals protected by a layer of mantle. Many species of mollusks that have a protective shell lime blend with the coat. Shells can be outside the body or inside the body. Octopuses are mollusks that have no shells at all.

There are more than 100,000 species of mollusks animals, ranging from tiny snails to giant squids. Most of these animals living waters, and only a few are living on land. Several types of mollusks such as mussels are almost never move at all. Mussels attach themselves somewhere and looking for food just by opening their shells. There is also a single-legged molluscs.

Parasitism

Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with life stages that went beyond one host, which are now called macro parasites.

Parasites can now also refer to micro parasites, which are typically smaller, such as viruses and bacteria and can be directly transmitted between hosts of one species.

Not like predators, parasites are usually much smaller than their host, even though both are special cases of consumer-resource interactions. Parasites show a high degree of specialization for their mode of life, and reproduce at a faster rate than their hosts.

Infection

An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease. Colloquially, infections are usually considered to be caused by microscopic organisms or micro parasites like viruses, prions, bacteria, and viroids, though larger organisms like macro parasites and fungi can also infect.

Hosts normally fight infections themselves via their immune system. Mammalian hosts react to infections with an innate response, often involving inflammation, followed by an adaptive response. Pharmaceuticals can also help fight infections. The branch of medicine that focuses on infections and pathogens is infectious disease medicine.

Transduction

Transduction is the process by which DNA is transferred from one bacterium to another by a virus. It also refers to the process whereby foreign DNA is introduced into another cell via a viral vector. This is a common tool used by molecular biologists to stably introduce a foreign gene into a host cell's genome.

When bacteriophages (viruses that infect bacteria) infect a bacterial cell, their normal mode of reproduction is to harness the replicational, transcriptional, and translation machinery of the host bacterial cell to make numerous virions, or complete viral particles, including the viral DNA or RNA and the protein coat. Transduction and specialized transduction is especially important because they explain how anti-biotic drugs become ineffective due to the transfer of resistant genes between bacteria.

Transformation

In molecular biology transformation is the genetic alteration of a cell resulting from the direct uptake, incorporation and expression of exogenous genetic material (exogenous DNA) from its surrounding and taken up through the cell membrane. Transformation occurs most commonly in bacteria and in some species occurs naturally. Transformation can also be effected by artificial means. Bacteria that are capable of being transformed, whether naturally or artificially, are called competent.

Transformation is one of three processes by which exogenous genetic material may be introduced into a bacterial cell, the other two being conjugation (transfer of genetic material between two bacterial cells in direct contact), and transduction (injection of foreign DNA by a bacteriophage virus into the host bacterium).