Biology B5 - Communicable diseases

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can lower the incidence by Cooking Food thoroughly and drinking clean water. growing bacteria in the lab: they are grown in a culture medium (e.h. Agar Plate). This contains: carbohydrates for energy creleased through respiration) Proteins for growth Minerals For Vital Processes A SUPPLY OF Oxygen (For respiration) warmth (Optimum temperatures for enzymes) method: Sterilise the innoculating LOOP by heating it until it is red hot in the flame on a bunsen burner. Let it COOL (do not Put down or blow on it as it COOLS). DIP the Sterilised hoop in the bacteria you want to grow and use it to make zigzag streaks across the surface of the agar. Put lid back on dish as quickly as possible to avoid air born contamination. seal the lid of the Petri dish With tape to prevent microorganisms from the air contaminating the culture or microbes from the Culture escaping. Do not seal all the way around the edge as oxygen needs to get in the dish to Prevent harmful anerobic bacteria from growing. Label Petri dish and Store UPSide down to Stop condensation Falling onto the agars surface. Bacteria in liquid cutture medium- Stenle solid cuture medium -8 Bacteria spread on sold outure medium Adhesive tape, Preventing bacterial growth: temperature raise or lower the temperature, this prevents the bacterial enzymes from Working and Will Prevent their growth. disinfectant Chemicals used to kill bacteria in the environment. antiseptic - a type of disinfectant that is safe to use on human skin. antibiotics a Chemical that can be ingested to help kill bacteria. Ignaz semmelweis: was a doctor in the 1850s. Many women in hospitals were dying from Childbed Fever FOLLOWing Childbirth. semmelweis observed at this time that doctors were not washing their hands between dissecting dead bodies and delivering babies. semmelweis hypthesised that they were carrying the cause of the pathogen between the Corpses and the new mothers. FOLLOWIng these observations, semmelweis insisted that doctors and midwives wash their hands before and after delivering babies. This resulted in the number of deaths from Childbed Fever decreasing. hygiene- Simple Hygiene prevents the spread of Pathogens. Examples include handwashing. Using disinfectant, keeping raw meat away from cooked meat etc. isolation - Keeping a patient isolated Will help to reduce the spread. Examples include influenza FLU - Stay off work. SCHOOL. vectors destroy or control the number of vectors, these are organisms that carrya Pathogen between other organisms. For example, mosquitoes carry malaria, rats carry a bacterium that causes salmonella. vaccination - a small amount of a harmless pathogen is injected into the body, so that your immune system will be prepared. For example, babies are vaccinated against the FOLLOWIng diseases: diptheria, tetanus, Polio and meningitis B. Viral diseases: measles is spread by droplets. The symptoms include fever, red, blo+Ch Skin rash, and it can lead to blindness and brain damage. We can treat it by vaccination cat 2 months Old). Infection usuallly clears in 7-10 days. Take Paracetamol, drink water, close curtains. HIV/AIDS iS Spread by direct contact (e.g. sexual contact, exchange of body Fluids). The Symptoms of the disease include mild FLU-like symptoms at the start. Immune system badly affected so can not deal with infections. There is no cure of vaccines however antiretroviral drugs can help the onset of AIDS. tobacco mosaic Virus is spread by direct contact. vectors-insects. The symptoms include discoloured mosaic pattern on leaves. Stunted growth, both of these are due to no Photosynthesis. There is no treatment. To prevent many farmers grow Tmv-Resistant CroPS. GOOd hygiene can also reduce the spread. Bacterial diseases: salmonella is spread through infected and undercooked meat. The symptoms develop Within 8-72 hours and include fever, abdominal cramps, vomiting and diarrhoea. The treatment includes antibiotics Which is given to the young and elderly where it can be fatal due to dehydraion. In the UK Poultry (Chickens, turkeys etc.) are vaccinated against salmonella. gonorrhoea is spread through sexual contact. Symptoms include discharge and in Pain Whilst Urinating. It can lead to Pelvic pain, ectopic Pregnancies, and infertility. Babies born can have eye infections which can lead to blindness. bacterial diseases in Plants is Spread by direct contact. Symptoms include crown galls -Unspecialised cells grow on the roots and shoots. This is due to the bacteria inserting Plasmids into the Plant cells leading to cellular growth. There is no treatment. crops are genetically engineered so they are resistant to the bacterium. rose black Spot: It is a fungal disease. Purple or black spots develop on leaves. Which often turn yellow and drop early. It affects the growth of the plant as Photosynthesis is reduced. It is Spread by water or Wind. It can be treated by using Fungicides (a chemical that is SPrayed on) and/or removing and destroying the affected leaves. Malaria: caused by the Protist (single-celled organism), Plasmodium. It is spread by a vector. mosquito. Which is passed into the blood. Malaria causes recurrent episodes of Fever and can be fatal. The spread of malaria is controlled by Prevening the vectors, mosquitoes. From breeding (e.g. spraying insecticides) and by using mosquito nets to avoid being bitten. Human defence responses: eyes Produce tears that contain enzymes that digest Potential Pathogens. NOSE-contains hairs and Produces mucus that traps the pathogens. Trachea- Produces mucus and contains cilia. MUCUS is produced by cells lining the lungs and airways and then is wafted UP by the Cilia to be removed from the body either by blowing your nose or swallowing it. Stomach hydrochloric acid Kills Pathogens. Skin - covers the body and acts as a barrier. It produces antibacterial secretions Which Kill bacteria. If these break, Platelets Clot the blood to form a scab. role of White blood cell: ingesting microorganisms - this protects you against disease as some White blood cells ingest (take in) Pathogens, digesting and destroying them so they cannot make yOU ill. Produing antibodies - it protects you against disese as some white blood cells Produce Special Chemicals called antibodies. These target particular bacteria or Viruses and destroy them. You need a unique antibody for each type of pathogen. When your White blood cells have produced antibodies once against a particular pathogen, they can be made very quickly if that Pathogen gets into the body again. This S+OPS you getting the disease twice. producing antitoxins - this protects you against disease as some White blood cells Produce antitoxins. These counteract (cancel out) the toxins released by Pathogens. Bacterium Antibody White blood cell Antitoxin molecule Toxin and antitoxin joined together Antigen -White blood cell - Bacterium Antibody atta+Ched to antigen White blood cell TOXin molecule Baterium nitrate deficiency - needed to convert sugars into proteins for growth. Problem reduced growth. Symptoms = Stunted growth. magneesium deficiency- needed to make Chlorophyll for Photosynthesis. Problem reduced growth due to lack of Photosynthesis. Symptoms = yellowing of leaves. Chlorosis. = Plant defences: Physical defence response to resist invasion of microorganisms. E.9. cellulose cell walls. TOUgh Waxy Cuticle on leaves. Layers of dead cells around stems (bark on trees) and I leaves Which fall off in autumn so pathogens removed. Chemical Plant defence responses. E.g. antibacterial Chemicals. Poisons to deter herbivores. Mechanical adaptions. E.g. thorns and hairs deter animals. Leaves that drop or curl When touched, dislodges insects. Mimicry to trick animals.