Virus gondong wikipedia

Viruses are submicroscopic, which means that you cannot see them in the microscope. What's interesting about viruses is that they have two or three components. Starting from the inside, you will have a nucleic acid, which can be either RNA or DNA, and in both cases the nucleic acid can be either single-stranded or double-stranded.

Then surrounding the nucleic acid will be a protein coat that's in the form of capsid, or little small units that are assembled in a certain way. That is what all viruses have.

Now, some viruses will also have an envelope which they obtain as they emerge from the cell. Being diagnosed with cancer is a shock that hits you hard. And yet almost half of all cancer cases could be prevented.

Smoking alone triggers about every fifth tumor. The toxic cigarette smoke does not only cause lung cancer but many other kinds of tumors as well. Smoking is the most frequent self-imposed cause for cancer, but not the only one. In second place of cancer-causing agents: obesity. Why it causes cancer? Enhanced insulin levels increase the risk of almost all sorts of cancer, especially when it comes to kidney, gall bladder, and oesophagus cancer. Overweight women produce increasing amounts of female sex hormones in their fat tissue and hence have a higher risk for uterine or breast cancer.

People who don't move enough are especially likely to get cancer. Long-term studies show that exercising prevents tumors. After all, working out lowers the insulin levels while preventing you from gaining weight. Even just going for a walk or a bike ride makes a big difference. Alcohol promotes tumors in the oral cavity, the throat and the oesophagus. The combination of smoking and drinking is especially dangerous and increases the risk of cancer up to a hundredfold.

Red meat can cause intestinal cancer. The exact cause has not yet been determined, but long-term studies show a significant correlation between the consumption of red meat and intestinal cancer. Beef is especially dangerous, but even pork can cause cancer to a minor degree. Meat consumption increases the risk of cancer one and a half times.

Fish, however, prevents cancer. When barbecuing meat, carcinogenic substances are released, such as polycyclical aromatic hydrocarbons. It has been proven in animal experiments that these chemical compounds can cause tumors. However, long-term studies with humans have not yet unambiguously proven the same.

A good diet consisting of vegetables, fruits and dietary fibers can prevent cancer. However, when conducting long-term studies researchers found that a healthy diet has less impact on cancer prevention than previously assumed.

It only decreases the risk of getting cancer by a maximum of 10 percent. While sunscreen protects the skin from sunburn, the skin absorbs too much radiation as soon as it starts getting tanned. X-rays harm genomes. With an ordinary radiogram the exposure is only minor. Magnetic resonance imaging is harmless. Human papillomaviruses can cause cervical cancer. Hepatitis B and C can cause hepatocytes to degenerate. The bacterium helicobacter pylori pictured above settles in your stomach and can cause stomach cancer.

But not all hope is lost. You can get vaccinated against many of these pathogens and antibiotics help fight helicobacter pylori. The oral contraceptive pill slightly increases the risk of getting breast cancer, but at the same time it strongly decreases the risk of getting ovarian cancer.

All in all the pill is more protective than harmful, at least when it comes to cancer. Half of all cancer cases are caused by the wrong genes or simply age. Brain cancer is particularly likely to be inherited. The immune system needs many different types of fuel. Fruit and vegetables provide them. Your diet should be healthy and colorful: Oranges, red peppers, green leafy vegetables and red cabbage provide a potpourri of vitamins, and are especially rich in natural vitamin C.

In order to ensure your immune system is top-top, make sure you have all the necessary immunizations. A virus that is outside of a host cell is known as a virion.

Not only are viruses microscopic, they are smaller than many other microbes, such as bacteria. Most viruses are only 20— nanometers in diameter, whereas human egg cells, for example, are about micrometers in diameter, and the E. Viruses are so small that they are best viewed using an electron microscope , which is how they were first visualized in the s. Viruses generally come in two forms: rods or spheres. However, bacteriophages viruses that infect bacteria have a unique shape, with a geometric head and filamentous tail fibers.

No matter the shape, all viruses consist of genetic material DNA or RNA and have an outer protein shell, known as a capsid. There are two processes used by viruses to replicate: the lytic cycle and lysogenic cycle. Some viruses reproduce using both methods, while others only use the lytic cycle. In the lytic cycle, the virus attaches to the host cell and injects its DNA.

Then fully formed viruses assemble. These viruses break, or lyse, the cell and spread to other cells to continue the cycle. Like the lytic cycle, in the lysogenic cycle the virus attaches to the host cell and injects its DNA. In humans, viruses can cause many diseases. For example, the flu is caused by the influenza virus.

Typically, viruses cause an immune response in the host, and this kills the virus. However, some viruses are not successfully treated by the immune system, such as human immunodeficiency virus, or HIV.

This leads to a more chronic infection that is difficult or impossible to cure; often only the symptoms can be treated. Unlike bacterial infections, antibiotics are ineffective at treating viral infections. Viral infections are best prevented by vaccines, though antiviral drugs can treat some viral infections. Most antiviral drugs work by interfering with viral replication. Some of these drugs stop DNA synthesis, preventing the virus from replicating.

Although viruses can have devastating health consequences, they also have important technological applications. Viruses are particularly vital to gene therapy.