Biology 2.2 Internal Assessment (3 credits) Analyse the biological validity of information presented to the public

You tube clips (What is HPV?) (HPV and Pap smear testing) feature=relmfu (HPV and genital warts) feature=relmfu (vaccination against HPV)

You tube clips (Interviewing young people about HPV and general info) (Interviewing young people about HPV and general info) tch-vrec (General info about HPV) tch-vrec (General info about HPV and cervical cancer) ated (How HPV invades epithelial cells – advanced) ated ated (How HPV invades epithelial cells – brief) ated ated (How HPV causes benign lesions and cervical cancer) ated

You tube clips - vaccination &feature=related (How does HPV vaccine work?) &feature=related &feature=related (How vaccines work) &feature=related U&list=LPA4s4FH2EJa0&index=1&feature=plcp (Gardasil pros and cons) U&list=LPA4s4FH2EJa0&index=1&feature=plcp (How HPV vaccinations work).

Biology 2.2 Internal Assessment In this achievement standard you will be learning about viruses and vaccination. We will be focusing on the Human Papilloma Virus (HPV) and you will be analysing the biological validity of information presented to the public about the vaccination for this virus. Biological validity means whether the information is accurate, inaccurate or biased.

Viruses are ultramicroscopic organisms - many times smaller than bacteria, and amongst the smallest organisms known. Basically, viruses are just a fragment of genetic material (a piece of DNA or RNA) inside a protective protein coat. What are viruses?

Viruses come in many different shapes Influenza virus Tobacco mosaic virus Bacteriophage virus Human Papilloma virus

Structure of viruses A virus consists of DNA or RNA enclosed in a protein coat.

Are viruses living? Let’s apply MRSGREN

Movement- All living things move in some way eg- animals move to find food and move away from predators. Reproduction- All living things reproduce to keep their species in existence. Sensitivity- All living things are sensitive to their surroundings due to their sense organs. Growth- All living things grow larger during their lifetime, by cell division. Respiration- All living things turn their food into energy by respiration. Excretion- All living things must excrete waste products. Nutrition- All living things obtain food in some way eg- animals by eating and plants by photosynthesis.

So, are viruses living? Viruses do NOT feed on anything! Viruses do NOT respire! Viruses do NOT produce any waste products! Viruses do NOT grow and are NOT made of cells! Viruses do NOT sense their surroundings! The only thing viruses CAN do is REPRODUCE!! They are said to be ‘on the edge of life’ because they act as a non-living chemical until they come in contact with a host cell.

In 1898, Friedrich Loeffler and Paul Frosch found evidence that the cause of foot-and- mouth disease in livestock was an infectious particle smaller than any bacteria. This was the first clue to the nature of viruses, genetic entities that lie somewhere in the grey area between living and non-living states.

How viruses reproduce Viruses can only reproduce inside living cells. The virus latches on to a host cell and penetrates its cell membrane, injecting its genetic material into the cell. Once inside, the viral DNA breaks into the nucleus and takes over the host cell's DNA. The host cell’s DNA is reprogrammed by the virus to make new viral DNA and protein coats. Eventually hundreds of new viruses fill the whole host cell and burst it open, releasing the viruses.

The Human Papilloma Virus (HPV) The human papilloma virus (HPV) is a very common virus. It is spread by skin to skin contact and most people will have it at some point in their lives. There are over 100 different strains of HPV. Strains 1 and 2 cause warts on the feet and hands. Papilloma is the medical term for wart.

HPV is also spread by sexual contact and it is estimated that 75% of people who are sexually active are infected with HPV. Most of the time, a person with HPV has no symptoms and your immune system will get rid of the infection. Some strains of HVP can cause low grade lesions and genital warts in both males and females. These strains of HVP are benign – they do not cause cancer, and will often clear up on their own over time. However, about 20 strains of HVP can cause high grade lesions and lead to cancer, particularly cancer of the cervix in women.

Cervical cancer is the second leading cause of death from cancer in women worldwide. 99% of cervical cancers are caused by HPV.

How do HPV infections occur? The human papilloma virus reproduces inside epithelial (skin) cells in the cervix. If it enters cells on the surface of the cervix, HVP will clear up when these cells are shed. If it passes through micro- abrasions (tiny cracks) in the cervix, it can enter the basal epithelial cells. When these cells reproduce, the virus is passed on to new cells. These infections take longer to clear and can lead to genital warts and cervical cancer. micro-abrasion

How HPV causes genital warts Genital warts are formed when HPV enters basal epithelial cells. DNA from the virus enters the cell’s nucleus but remains separate from the cell’s DNA. The presence of HPV causes the epithelial cells to multiply at a faster rate, producing warts. HPV spreads to new cells as they form and the virus is released when surface cells are shed.

How HPV causes cervical cancer Cervical cancer occurs when HPV DNA gets inserted into the epithelial cell’s DNA. When this happens, viral proteins called E6 and E7 are produced. These proteins disrupt normal cell division, resulting in uncontrolled growth of abnormal epithelial cells (cervical cancer).

Detecting cervical cancer HPV infection and cervical cancer can be detected by a PAP smear test. Cells are collected from the cervix and observed under a microscope to check for any abnormalities. Colposcopy is used to check for genital warts. A weak vinegar solution is placed on the cervix which makes the warts more visible and easily detected. A biopsy can also be done to check for further abnormalities. This involves taking a small sample of cervical tissue. A HPV DNA test can also be used to test whether HPV or the E6 and E7 proteins it produces are present.

Preventing HPV infection Limit sexual partners. Use a condom every time you have sex. Do not smoke. Smoking weakens your immune system so you are less able to fight viral infections. Get immunised against HPV.

Controlling Viruses Viral diseases are difficult to control because viruses have a very high mutation rate which allows them to rapidly evolve into new forms. Viruses cannot be controlled by antibiotics because antibiotics work by destroying cell walls or cell membranes and viruses do not have these structures. Once you have been exposed to a virus, your immune system will make antibodies to fight the infection. Some viral diseases can be controlled by vaccinations.

How our immune system works Our immune system consists of several types of white blood cell which are produced in our bone marrow. One type of white blood cell, called lymphocytes, produce special Y-shaped chemicals called antibodies which lock onto viruses and destroy them or prevent them from entering our cells. These antibodies stay in your blood ready to attack the virus should it enter your body again. Each type of virus has its own specific antibody.

Lymphocytes These white blood cells make special chemicals called ANTIBODIES.

How do vaccinations work? Vaccinations contain a weakened or inactive form of the virus. The vaccine is injected into your bloodstream which ‘kick-starts’ your immune system into producing antibodies to fight the virus.

The Gardasil Vaccination The Gardasil vaccine doesn’t contain the actual HPV virus, just purified, inactive proteins that come from the virus. Proteins from HPV types 6, 11, 16 and 18 are used – these are the main types of HPV that cause genital warts and cervical cancer. Gardasil is given as three injections over a six month period. You need to complete the course of injections to be fully protected from HPV. To be most effective, the vaccine should be given before a woman becomes sexually active.