Communicable Diseases and PathogensAQA GCSE Biology: Flashcards

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Define what a pathogen is.

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Define what a pathogen is.: A pathogen is a microorganism that causes disease. It can be a bacterium, virus, fungus, or protist that invades the body and damages cells or produces toxins.
Name the four main types of pathogens.: The four main types of pathogens are: bacteria, viruses, fungi, and protists.
Describe the two ways pathogens cause disease.: Pathogens cause disease by: (1) producing toxins that damage cells or tissues, and (2) directly damaging or destroying cells by invading them.
What is tuberculosis and what type of pathogen causes it?: Tuberculosis (TB) is a bacterial disease caused by the bacterium Mycobacterium tuberculosis. It primarily affects the lungs and is spread through the air via coughing and sneezing.
What is Salmonella and how is it spread?: Salmonella is a bacterium that causes food poisoning characterised by diarrhoea, fever, and abdominal cramps. It is spread through contaminated food and water.
What is gonorrhoea and what type of pathogen causes it?: Gonorrhoea is a sexually transmitted bacterial infection caused by the bacterium Neisseria gonorrhoeae. It is spread through direct contact during sexual intercourse.
What is measles and how is it transmitted?: Measles is a viral disease characterised by fever and a red rash. It is spread through the air by droplets when an infected person coughs or sneezes.
Describe HIV and how it is spread.: HIV is a virus that attacks the immune system and can lead to AIDS. It is spread through direct contact with blood or body fluids, including sexual contact and sharing contaminated needles.
What is tobacco mosaic virus and which organism does it infect?: Tobacco mosaic virus (TMV) is a viral pathogen that infects tobacco plants and other plants, causing mottled, discoloured leaves and stunted growth.
What is rose black spot and what type of pathogen causes it?: Rose black spot is a fungal disease of rose plants caused by the fungus Diplocarpon rosae. It causes dark blotches on leaves, leading to yellowing and defoliation.
What is malaria and what type of pathogen causes it?: Malaria is a disease caused by a protist of the genus Plasmodium. It is transmitted through the bite of an infected Anopheles mosquito and causes fever, chills, and anaemia.
Name four methods by which diseases are spread.: Diseases are spread by: (1) direct contact with an infected person, (2) water (contaminated drinking water), (3) air (respiratory droplets), and (4) vectors such as insects.
Explain what a disease vector is and give an example.: A disease vector is an organism that transmits a pathogen from one host to another without causing disease in itself. An example is the Anopheles mosquito, which transmits the malaria protist.
Describe three ways the spread of communicable diseases can be reduced or prevented.: The spread of communicable diseases can be reduced by: (1) vaccination to provide immunity, (2) hygiene measures such as handwashing and food hygiene to prevent transmission, (3) antibiotics to treat bacterial infections, (4) quarantine to isolate infected individuals, and (5) using barriers such as condoms to prevent direct contact.
Explain how vaccination prevents the spread of disease.: Vaccination introduces a weakened or inactive form of a pathogen, allowing the immune system to produce antibodies and memory cells without causing full disease. If the person later encounters the actual pathogen, they are already immune, preventing infection and transmission to others.