Biodiversity and classification of microorganisms Grade 11 IEB Life science Basic structure and general characteristics VIRUSES BACTERIA PROTISTA FUNGI Small Have genetic material (DNA or RNA) Obligate intracellular parasites (need host to reproduce) Have capsid Prokaryotes Don’t have well defined membrane bound organelles Circular DNA Cell membrane made of phospholipid and protein Cell wall made of peptidoglycan Eukaryotic Have membrane bound organelles Most are aquatic Most are unicellular Eukaryotic Unicellular or multicellular Have long thread-like hyphae (together make the mycelium) Cell wall made of chitin and polysaccharides 2 How viruses play a role in their environment Viruses cause diseases and are said to be pathogenic. In humans, viruses are responsible for diseases such as HIV/AIDS, Covid-19, poliomyelitis, chickenpox, herpes and influenza. Viruses are useful in the study of genes. Viruses have either DNA or RNA which is surrounded and protected by an outer protein coat or capsid. All other living organisms have both DNA and RNA. Viruses affect the evolution process of the organism they use as a host. Viruses play an important global role in the recycling of nutrients through food webs How protists play a role in their environment Protists are primary producers, direct food sources and can act as decomposers Many protists are also parasites and can cause harm to humans, animals How bacteria play a role in their environment Bacteria are used to make certain foods such as cheese, yoghurt and alcohol (fermentation) Certain bacteria can be used to make medicines such as insulin to treat people with diabetes Bacteria help you to digest your food Bacteria are very important in ecosystems and food webs because they are a main decomposer, so they can put nutrients and minerals back into the earth. How fungi play a role in their environment Fungi are very important in soil diversity Fungi can transform nutrients to make them available for plants to use Some fungi are also decomposers Fungi are important contributors to cycling carbon through the food web Symbiotic relationships The relationship between two organisms Nitrogen fixing bacteria symbiotic relationship with plants Some plants such as legumes are able to form symbiotic relationships with nitrogen-fixing bacteria called Rhizobia. The bacteria forms nodules on the plant’s roots. This way, the plant can supply the bacteria with certain nutrients that the bacteria would otherwise struggle to obtain, and the bacteria can fix atmospheric nitrogen gas into ammonia that the plant can use. E. Coli symbiotic relationship with the human digestive system E.coli relies on the intestinal contents for nutrients and humans can derive certain vitamins from E.coli, particularly vitamin k, which is required for the formation of blood clotting factors. 4 HIV/AIDS HIV (human immunodeficiency virus) is a virus that attacks the body’s immune system. If HIV is not treated, it can lead to AIDS (acquired immunodeficiency syndrome). There is currently no effective cure. Once people get HIV, they have it for life. But with proper medical care, HIV can be controlled. People with HIV who get effective HIV treatment can live long, healthy lives and protect their partners. Treatment: HIV treatment (antiretroviral therapy or ART) involves taking medicine as prescribed by a health care provider. HIV treatment reduces the amount of HIV in your body and helps you stay healthy. There is no cure for HIV, but you can control it with HIV treatment. Most people can get the virus under control within six months. HIV treatment does not prevent transmission of other sexually transmitted diseases. 5 TUBERCULOSIS Tuberculosis (TB) is a potentially serious infectious disease that mainly affects the lungs. The bacteria that cause tuberculosis are spread from person to person through tiny droplets released into the air via coughs and sneezes. Treatment: As TB is caused by a bacterium, it can be treated with antibiotics, however, some strains of mycobacterium tuberculosis can become resistant to certain antibiotics, so a combination of many different type of antibiotics must be used as effective treatment. The courses of antibiotics must ALWAYS be completed. There is also a TB vaccine that is given to children in areas where TB is endemic. 20XX presentation title 6 Malaria Malaria is a serious disease that spreads when you’re bitten by a mosquito infected by tiny parasites. When it bites, the mosquito injects malaria parasites into your bloodstream. Malaria is caused by the parasitic protists, not by a virus or by a type of bacterium. Treatment: It’s important to start treating malaria as soon as possible. Your provider will prescribe medications to kill the malaria parasite. Some parasites are resistant to malaria drugs. Some drugs are given in combination with other drugs. The type of parasite will determine what type of medication you take and how long you take it. 7 Athlete’s foot Athlete’s foot, or tinea pedis, is an infection of the skin and feet that can be caused by a variety of different fungi. Although tinea pedis can affect any portion of the foot, the infection most often affects the space between the toes. Athlete’s foot is typically characterized by skin fissures or scales that can be red and itchy. Treatment: Antifungal creams are generally prescribed to help treat athlete’s foot.
