Year 9 Biology Micro-organisms and Disease

Year 9 Biology Task 1: Notes A disease is anything that causes your body to stop working properly One cause of disease is bacterial infection. Bacteria are a type of micro-organism

Year 9 Biology Micro-organisms Micro organisms are the tiny living things that can only be seen using a microscope. They are everywhere, including the food you eat and you!

Year 9 Biology Ignaz Semmelweiss Ignaz Semmelweiss was a doctor in the mid 1800s He wondered why so many women died of ‘childbed fever’ soon after giving birth. He also noticed that student doctors carrying out work on dead bodies did not wash their hands before delivering a baby. When he got them to wash their hands in calcium chloride solution before delivering babies, fewer women died. He concluded that something was carried by the doctors from the dead bodies to the women.

Year 9 Biology Doctors / Scientists Pasteur and Lister Pasteur proved that there were ‘germs’ in the air and that they carried infection and disease. Lister developed a special soap called carbolic soap. He insisted that all medical instruments, dressings and even surgeons should be cleaned with it before any operation. Lister’s patients stayed healthy. Chemicals that are used to clean wounds or get rid of sores are called antiseptics.

Year 9 Biology Why is it important to keep them clean? What is an antiseptic / disinfectant? What is now used on wards for visitors? Why? Task 2: Hospitals

Year 9 Biology Bacteria Bacteria are examples of decomposers that convert dead plant and animal matter into nutrients that make plants grow In some animals bacteria can help with digestion Bacteria that cause disease are called pathogens Infectious diseases are diseases that can spread.

Year 9 Biology Task 3: microbes List the 3 main types of microbe and a disease they cause Bacteria (cause cholera, boils, MRSA, typhoid, tuberculosis) Viruses (cause warts, herpes, polio, flu, mumps, measles, smallpox) Fungi (cause athlete’s foot, ringworm) A disease causing organism is called a pathogen

Year 9 Biology Questions 1.What is a disease? 2.What are the main causes of disease? 3.What is a decomposer? 4.What is a pathogen? 5.What does infectious mean?

Year 9 Biology First line of defence skin fluids hairs in nose Acid in stomach vomiting/diarhoea

Year 9 Biology Second line of defence Neutrophils (large WBC) consuming bacteria causing pus Lymphocytes and macrophages (other WBC) are release from lymph nodes Macrophages engulf/destroy bacteria Lymphocytes make antibodies that provide future protection.

Year 9 Biology

Micro-organisms also have enzymes Temperature is increased during an infection so pathogens cannot function as efficiently

Year 9 Biology Summary task The _______ which cause infectious diseases are known as ________ Once __________ and __________ get inside your body they _________ rapidly. They ________ your tissues and may produce _______ of disease. Bodys first line of defence include _________ Lymphocytes produce _________. Macrophages _______ pathogens. A __________ can also reduce the activity of a pathogen. Skin Toxinstemperature viruses acid engulf micro organisms reproducepathogensAntibodies damagesymptomsbacteria