UNIT 2 – BIOLOGICAL WORLD Fungi


Fungi cannot produce their own food, as they do not contain chlorophyll. Instead, they must feed on dead plant and animal material or on parts of other organisms, e.g. dead human skin cells.


Diseases caused by fungi include: • athlete’s foot • ringworm


? TEST TUBE


14. Are disease-causing fungi parasites? Explain your answer.


:Fig. 10.15 Athlete’s foot is a fungal infection Prevention and treatment


Most disease-causing micro-organisms are present in the air we breathe or on surfaces we touch. Some pathogens enter the body in undercooked food or contaminated water. To reduce the chances of becoming ill:


• Practise good hygiene. Wash your hands with warm water and soap for at least 20 seconds or use hand sanitiser.


• Practise good coughing etiquette. Use a tissue and dispose of it safely.


• Social distance when necessary. Do not go to school, college or work if you are displaying symptoms.


• Cook food properly. • Make sure drinking water is clean.


• Get adequate sleep and exercise and reduce stress and anxiety.


:Fig. 10.16 Wash your hands with warm water and soap


EXPERIMENTAL INVESTIGATION 10.4 How can we investigate if micro-organisms are present on the laboratory bench?


Equipment Disinfectant


Chopping board Sterile gloves


Method


1. Disinfect a chopping board using alcohol or disinfectant.


2. Wearing sterile gloves, place a slice of bread on the chopping board.


3. Drop 5–10 cm3 of sterilised water onto the upper surface of the slice of bread.


4. Carefully pick up the slice of bread and place the moist upper surface in contact with the non-sterilised laboratory bench for 5–10 seconds.


102 Elements of Science 


SAFETY • Keep the bags containing the micro-organisms sealed.


• Your teacher will sterilise the bags before disposing of them.


Fresh wholegrain bread Plastic droppers


Sterilised water (boiled in a pressure cooker and then stored in a sterile bottle)


Sandwich bag Incubator


Magnifying glass


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