Virus and Bacteria

A virus is a capsule of protein that contains genetic material. A virus cannot reproduce on its own; it must infect a living cell to grow. Bacteria – Bacteria are one-celled organisms that live on their own. They can multiply and reproduce by subdivision Bacteria and viruses cause many of the diseases we are familiar with and may sound synonymous; they are greatly different from each other. [pic] o They differ greatly in size.
The biggest viruses are only as large as the tiniest bacteria.Viruses are microscopic; they range in size from about 20 to 400 nanometers in diameter (1 nanometer = 10-9 meters). By contrast, the smallest bacteria are about 400 nanometres in size. o Another difference is their structure. Bacteria are complex compared to viruses. A typical bacterium has a rigid cell wall and a thin, rubbery cell membrane surrounding the fluid, or cytoplasm inside the cell. A bacterium contains all of the genetic information needed to make copies of itself—its DNA—in a structure called a chromosome.
In addition, it may have extra loose bits of DNA called plasmids floating in the cytoplasm.Bacteria also have ribosomes, tools necessary for copying DNA so bacteria can reproduce. Some have threadlike structures called flagella that they use to move. o A virus may or may not have an outermost spiky layer called the envelope. All viruses have a protein coat and a core of genetic material, either DNA or RNA. The main difference between viruses and bacteria is the way they reproduce. Bacteria, given the proper nutrients, can grow and reproduce on their own.

But viruses cannot “live” or reproduce without getting inside some living cell, whether it’s a plant, animal, or bacteria.Viral vs. Bacterial Reproduction Bacteria contain the genetic blueprint (DNA) and all the tools (ribosomes, proteins, etc. ) they need to reproduce themselves. Viruses are moochers. They contain only a limited genetic blueprint and they don’t have the necessary building tools. They have to invade other cells and hijack their cellular machinery to reproduce.
Viruses invade by attaching to a cell and injecting their genes or by being swallowed up by the cell. Here’s an example of viral infection. These are T4 bacteriophages. They are a kind of virus that infects bacteria.Here they are landing on the surface of an E. coli bacterium. The bacteriophage cuts a hole in the E.
coli’s cell wall. It then injects its genetic material into the bacterium. By taking over the E. coli’s genetic machinery, the viral genes tell the bacterium to begin making new virus parts. These parts come together to make whole new viruses inside the bacterium. Eventually so many new viruses are made that the E. coli bursts open and dies, releasing all those new viruses to infect more cells! Some diseases caused by virus and bacteria:Name of the disease |Caused by |Name of the microbes | |Polio |Virus |polio | |Pneumonia |Virus / Bacteria |influenza virus (flu) | | | |respiratory syncytial virus (RSV) | |Hepatitis |Virus |Hepatitis A Virus | | | |Hepatitis B Virus | |Mumps |Virus | | |Bronchitis |Virus |respiratory syncytial virus (RSV) | |AIDS |Virus |human immunodeficiency virus(HIV) | |Tuberculosis |Bacteria |Mycobacterium tuberculosis | |Tetanus |Bacteria |Clostridium tetani | |Anthrax |Bacteria | | |Diphtheria |Bacteria | | |Chicken Pox |Virus |varicella-zoster (VZV) |How bacteria and viruses enter the body To cause disease bacteria have to gain access to the body.
The ways in which a bacteria can get access to an animal body are:• Cuts• Contaminated food or water• Close contact with an infected person• Contact with the faces of an infected person• Breathing in the exhaled droplets when an infected person coughs or sneezes• Indirectly, by touching contaminated surfaces – such as taps, toilet handles, toys and nappies.Viruses are spread from one person to another by:• Coughs• Sneezes• Vomits• Bites from infected animals or insects• Exposure to infected bodily fluidsCuring a bacterial infection The body reacts to pathogenic bacteria by increasing local blood flow (inflammation) and sending in cells from the immune system to attack and destroy the bacteria.Antibodies produced by the immune system attach to the bacteria and help in their destruction. Serious infections can be treated with antibiotics, which work by disrupting the bacterium’s metabolic processes. The body’s response to viral infection Viruses pose a considerable challenge to the body’s immune system because they hide inside cells. This makes it difficult for antibodies to reach them. However, special immune system cells, called T-lymphocytes, can recognize and kill cells containing viruses.
Many viruses, when released from infected cells, will be effectively knocked out by antibodies, produced in response to infection or previous immunization.Antibiotics are useless against viral infections. Antiviral drugs are available only for few viral diseases, such as influenza, herpes, hepatitis B and C and HIV, but research is ongoing. However, immunization is helpful in fighting viral infection. The large scale immunization has led to the eradication of small pox once one of the most feared viral disease. How to Know When You Need Antibiotics Don’t expect antibiotics to cure every illness. Antibiotics are only effective against bacterial infections.
In the past antibiotics were prescribed “just in case” the infection was bacterial rather than viral because it was thought that taking them “couldn’t do any harm”. Wrong.This very practice has contributed to the development of antibiotic resistant strains of bacteria. While the use of antibiotics depends on the specific diagnosis, basic guidelines include: Colds and flu are caused by viruses. They can’t’ be cured with antibiotics. Symptoms can last two weeks or more and should be allowed to run their course.

Cough and bronchitis are almost always caused by viruses.