Biology - Infetion and response Flashcards
How are infections caused
When a foreign pathogen invades an organism
How do viruses make us feel ill
Viruses are tiny non-living particles that can reproduce rapidly within the body. They invade host cells and use them to make new virus particles. Once the new virus particles are made, they cause the cell to burst. The cell damage makes us feel ill.
How does bacteria make us feel ill.
Bacteria are small living cells that either damage cells directly or by producing toxins. The toxins released by bacteria can damage the cells and tissues, making us feel ill.
What is fungi
Some fungi are single celled organisms that have a body made up of hyphae. the hyphae are able to grow and penetrate tissue, such as human skin or the surface of plants. The hyphae produce spores that can spread to other plants and animals.
How do protists make us feel ill
protists are single celled eukaryotes. Many are parasites, meaning they live on or inside other organisms. They are often transferred to the host organism by a vector such as insects or mosquitos. They make us feel ill by damaging our tissue.
4 ways to stop a disease from spreading
Vaccination
Isolation
Disease vectors
Hygiene
What is tobacco mosaic virus
Pathogen that affects plants such as tomatoes. They cause discolouration and stunt growth in plant as photosynthesis cannot take place.
What is HIV
HIV is spread through sexual contact or exchange of bodily fluids. It causes flu-like symptoms however unless antiretroviral drugs are taken successfully, HIV virus enters the lymph nodes and attacks the body’s immune system.
What is measles
Virus that can be spread by inhaling droplets. It causes a fever and red skin and can be fatal therefore most young children are vaccinated against it.
What is gonorrhoea
Sexually transmitted disease that causes pain when urinating and a thick yellow or green discharge from vagina or penis. Barrier methods include contraception such as condoms which can stop the bacteria spreading from person to person.
What is salmonella
disease we may get from food that has not been cooked properly or has been prepared in unhygienic conditions. Causes stomach pain, fever, vomiting and diarrhoea
What is rose black spot
Can be spread through water or air (wind). Causes purple or black spots on leaf of rose plants and eventually the leaves discolour and fall off. Makes it harder for the leaves to photosynthesise and so plant growth is slower. Must destroy and remove the discoloured leaves and use fungicides.
Examples of non-specific defenses of the body
Skin
Stomach acid
Mucus
Tears
How does skin fulfill its purpose of a non-specific defense
-waterproof barrier that pathogons cannot pass through
-good bacteria permanently live on the skin which covering the surface and preventing pathogens from growing on our skin.
How does the stomach fulfil its purpose of a non-specific defense
-glands in stomach wall produce hydrochloric acid, which destroys any pathogens in the stomach
How does mucus fulfil its purpose of a non-specific defense
Produced in the respiratory system and traps particles and bacteria from entering our airways
How do tears fulfil its purpose of a non-specific defense
contain enzymes that destroy any pathogens that make contact with our eye
what do anti toxins do
the immune system responds to toxins from bacteria by producing anti-toxins which neutralize the toxins and prevent them from causing harm
What are antibodies
White blood cells recognize foreign antigens (proteins) on the surface of pathogens and produce protein molecules called antibodies. antibodies are specific to particular pathogens
what is phagocytosis
White blood cells find the pathogen and engulf it by changing shape. The white blood cell ingests and digests the pathogen, destroying it.
How do memory cells work
Some white blood cells remain in the blood as memory cells from. If the same pathogen was to invade the body again the memory cells are able to produce antibodies faster , produce more antibodies, meaning that the antibody concentration remains in the body for longer
Why do antibiotics not work on viruses
viruses stay inside host cells and are not living cells