PCR is used every day to diagnose diseases, identify bacteria and viruses, match criminals to crime scenes, and in many other ways.
How does the body fight off a virus? The rhinovirus is one of the many viruses that can cause the common cold Viruses are infectious micro-organisms that require a living host to survive and multiply. When one enters your body, it invades and takes over cells, redirecting them to produce more of the virus.
How do our bodies defend us from viruses? When our bodies come under attack from a viral infection they launch a sophisticated defence known as 'the immune response'.
Our immune system is designed to recognise the cells that make up our bodies and repel any foreign invaders such as viruses.
They do this by using a huge army of defender cells which consist of different types of white blood cell. We make around a billion of them every day in our bone marrow. These T cells are crucial for killing other cells in the body that have been infected with germs.
Without T cells, other immune system cells, such as antibody-making B cells, can't work properly. If HIV is not treated the number of T cells drops steadily. Eventually, numbers fall to the point that the risk of infection greatly increases.
This end-stage is known as AIDS. White blood cells called macrophages destroy germs as soon as they detect them. However, if a viral infection begins to take hold we fight back using a more powerful defence of white cells called T and B lymphocytes. Antibodies are a special protein made by B cells.
They bind to a virus to stop it from replicating, and also tag viruses so that other blood cells know to destroy them. T cells have different roles to play.
Some act as guard dogs that raise the alarm when they detect invading viruses; others kill virus-infected cells directly, or help B cells to produce antibodies.
Once the virus has been cleared, a small number of these specialist B and T cells persist and retain an accurate memory of the destroyed virus. This means our immune systems are primed to prevent another infection from the same virus, without attacking the body's own cells by accident. This is known as 'acquired immunity'.Jul 22, · Earlier this year, the realms of law and new media collided when Lori Drew was hit with federal charges for creating a fake MySpace page and harassing a neighboring teenager, who then committed.
The Nucleic Acids The nucleic acids are the building blocks of living organisms. You may have heard of DNA described the same way. Guess what?
DNA is just one type of nucleic leslutinsduphoenix.com other types are RNA, mRNA, and tRNA. Pneumonia is a lung infection that can be caused by different types of germs, most commonly viruses.
Read about symptoms and treatment. The smallest objects that the unaided human eye can see are about mm long. That means that under the right conditions, you might be able to see an ameoba proteus, a human egg, and a paramecium without using magnification.
A magnifying glass can help you to see them more clearly, but they will. Learn the relative sizes of a human hair, dust mites, pollen, red cells, bacteria, ebola, and the rhinovirus (common cold) as they rest upon the head of a pin.
Jul 22, · Earlier this year, the realms of law and new media collided when Lori Drew was hit with federal charges for creating a fake MySpace page and harassing a .