Infection and response (1) Flashcards
(15 cards)
Virus-
Bacteria-
Fungi-
Protists-
How are they spread?
Virus- small microorganism (not a cell) that invades cells and rapidly reproduces, causing the cell to burst
Bacteria- small cells that release harmful toxins that cause pain
Fungi- small cells that grow and penetrate the skin, causing disease, and producing spores
Protists- single-cell eukaryotes carried by vectors and cause disease
-Air, water, direct contact
Examples of Viruses (3)
Measles- spread by droplets of infected mucus, causes a red rash and disease
HIV- spread by unprotected sex, attacks white blood cells, causes illness
TMV- causes a mottled effect on leaves so they can’t photosynthesise
Examples of Bacterial Infections-
Salmonella- caused by contaminated poultry, causes food poisoning
Gonorrhoea- spread by sexual contact, causes pain while urinating and thick, coloured discharge
Example of fungal and protist spread disease-
fungal- rose black spot causes spots on leaves and limits photosynthesis
Malaria- spread by mosquitos, causes a deadly fever
What does a lack of magnesium and nitrates do to a plant-
signs of plant disease-
magnesium- makes chlorophyll for photosynthesis. A lack of it causes yellowed leaves
Nitrates- make proteins for plant growth
Stunted growth, spots on leaves, rotting, discolouration
Plant defences:
Physical-
Chemical-
Mechanical-
Physical- waxy cuticle and layer of dead cells (eg tree bark) prevents pathogens from entering the plant
Chemical- some plants produce toxins to kill pathogens that come into contact with them
Mechanical- Features like thorns to deter predators
Mimicry to deter predation
non specific defences:
Skin-
Hairs and mucus-
Trachea and bronchi-
Stomach-
Tears-
Eyelashes-
Skin- acts as a barrier against pathogens entering the body, and secretes an antimicrobial substance
Hairs and mucus- trap inhaled pathogens in the nose
The trachea and bronchi- secrete mucus and are lined with cilia which are hair-like structures that move mucus to the back of the throat so it can be swallowed
Stomach- produces hydrochloric acid that kills pathogens
Tears- clear pathogens from eyes
Eyelashes-prevent pathogens irritating eyes
Immune system
Lymphocytes create antibodies and antitoxins, remember how to recreate them with memory cells and signal phagocytes to destroy the pathogen using enzymes
Phagocytes engulf and destroy the pathogen
Natural drugs (3)-
Aspirin- a painkiller found in willow branches
Digitalis- a drug that treats heart conditions, found in foxgloves
Penicillin- a mould with antibiotic properties
Painkillers-
Antibiotics-
Vaccines-
Painkillers- block the brain’s ability to register pain
Antibiotics- kill bacteria (however bacteria can mutate and become resistant)
Vaccines- a weakened pathogen injected into the bloodstream, so lymphocytes can develop antibodies to fight it without the risk of the person becoming ill
White blood cells remember how to create antibodies for the future
If you contract the real disease, the white blood cells can rapidly produce antibodies to neutralise it and prevent the person from becoming ill
pros and cons of vaccines
pros- creates herd immunity, reduces severity of being ill
cons- virus can mutate, expensive to create, side effects, not guaranteed results, ethical issues
How are monoclonal antibodies produced?
What are their uses?
- mouse injected with the target antigen
- B-lymphocyte cell removed from mouse
- B-lymphocyte fused with rapidly dividing tumour cell to create a hybridoma
- The hybridoma rapidly divides to form many clones of the white blood cell that produce the desired antibody
Uses- drug tests for sports, pregnancy tests, curing disease
How do pregnancy tests work
woman pees on test stick
Pregnant women have HCG hormone in urine
The test has mobile antibodies that bind to the hormone and move some blue beads
Two coloured strips form in a positive result, one being a control strip
Stages of drug development
- preclinical testing on human cells and tissues to determine efficacy, toxicity and dosage
- tests on live animals
- Clinical trials - tests on healthy humans with a low dosage
Test on ill people to find the optimal dosage
Implement a placebo drug to ensure patients’ feedback is legitimate
Tests are double blind so the patient and doctor don’t know if they have the drug or not to remove biased data - results aren’t published until they’re verified by other scientists
antigens-
antitoxins-
antibodies-
antigens- specifically shaped protein markers on the outside of pathogens
antitoxins- reduce the harmful effects of toxins
antibodies- proteins with a specific shape that bind to antigens and neutralises the pathogen
