Science+2

=Science= = Term 1 - Disease = In this unit we learnt about Disease, pathogens, and Immune response:

//__Pathogens:__//
A pathogen is an infection agent of "Germ". They can be single celled, multicellular, alive or non-living. There are several kinds of pathogens: //**Fungi**// **-** Living single or multi cellular eukaryotic organisms who are part of the taxonimic subgroup "Rozellida". Their cell walls contain chitin instead of cellulose but other than that they have a similar cellular structure to animals. They tend to grow in damp, dark areas. Some examples are mushrooms, yeast, and molds. They are vital for decompossition because they break down biomass. Some fungi can be extremely dangerous while others, like the button mushroom (pizza mushroom) are harmless. A fungal disease is caused when a fungi begins to emit toxins inside, or on the surface of your body. Some fungi can be killed off using anti-biotics or anti-fungals



//**Bacteria** -// Bacteria are found all over the earth... In fact, there are ten times as many bacterial cells in the human body as there are cells! However, we all depend on bacteria to live, because bacteria are responsible for a lot of the important processes that go on inside our body. We have a mutualistic Symbiotic relationship with these organisms. We have over 400 healthy bacteria in our intestinal track alone. Bacteria live off their cell by consuming waste, other pathogens, or nutrients. Bacteria can begin to become a problem if they form a parasitic relationship with the host. Having too much bacteria or having bacteria in the wrong place can also case disease. Pathogenic Bacteria cause illnesses including Cholera, Syphilis, Anthrax and the infamous Black Death (bubonic plague). They can be killed using Anti-Biotics.

//**Virus's** -// Virus's are non-living infectious agents that can only reproduce inside of living organelle. They are not capable of cell devision because they have no organelles or cell membrane. They consist mostly of RNA and DNA strands, and reproduce by transforming living cells into Virus generating organisms. They use the living cells machinery and metabolism to produce copies of themselves. Because they are using the host's own cells, virus's are hard to treat without causing harm to the host's cells. One proven method of treating viral infections is through the use of vaccines. A vaccine is a weakened version of the virus that is injected into your blood stream. Once your immune system naturally fights off the infection, your body builds up an immunity to that particular virus. Some virus's are harmless like those that cause the common cold, influenza, cold sores and chickenpox. However, virus's are also responsible for HIV/AIDS, Avian influenza, Ebola and SARS. //**Parasites** -//Parasites are multi-cellular organisms who live at the expense of their host. There are four different types of parasites, ecto (living on the surface eg. fleas) and endoparasites (live inside the organism, eg. Heartworm). In both cases, the parasite reproduces faster than their host. Some examples of parasites are hookworm, ticks and roundworm. There are a vast amount of parasites, and each one has a speciality. The oddest parasite I've heard of is "Cymothoa exigua" (The tongue fish) who is a water based crustacean that eats the tongue of it's host and attaches itself to the stub, to essentially become the fish's tongue.

=//**__Bread Mold Experiment:__**//= We conducted an individual class experiment to see what conditions were required for mold growth: I knew from my textbook that mold grew best in damp dark places, so I thought that I should test for humidity. Unfortunately, due to our lack of resources, we were unable to perform our experiment and had to make due with the first half of our write ups: We followed the scientific method: Question, Research, Hypothenuse, Variables, Procedure, Data, Processing, Analysis, Conclussion, Areas for Improvement and Safety Precautions.

=**//__Disease:__//**= As previously mentioned, pathogens are usually responsible for disease, but can be caused by a deficiency (Eg: Scurvy and vitamin C), by the lifestyle choices you make or they can be genetic. Lung cancer is not caused by pathogens, the leading cause of cancer is actually cigarettes, by killing off and weakening the tissues of the lungs, the smoker, is actually increasing the chance that cancerous cells will develop. Breathing problems like Asthma can occur when you spend the majority of your time in dusty or moldy places. Working in a factory or processing plant dealing with heavy metals or toxic chemicals can increase the likelihood of cancer, and cause breathing and heart problems. Addiction is also a factor to take into account, and that in turn is affected by your environment, social standing and personality. Here's a powerpoint I made to explain how lifestyle choices can have major effects on an individual's health: Genetic diseases (disorders) are slightly different. When babies are conceived, they receive 23 chromosomes from our mother and 23 from our father. Sometimes, the process goes wrong because of a dormant hereditary condition, events during the pregnancy or because of a freak accident when the chromatids were matching with their pair. A child with down syndrome, a disorder impairing cognitive abilities and growth, are born with a third 21st chromosome in all of their cells. Sickle Cell Anemia is a disease that causes the red blood cells in a fetus's body to develop as sycle shapes (a bit like a seed but flatter). Normal red blood cells live for approximately 120 days, which means the body will always have enough blood cells to carry CO2 and Oxygen around the body. Unfortunately, these alternative red blood cells only live for about 10 to 20 days and as a result, people with Sickle Cell Anemia suffer from frequent blood clots, and have mild to severe respiratory problems.