Infection and Response Flashcards
How do diseases caused by viruses, bacteria, protists and fungi spread
Droplet infection, direct contact, water and food or vectors(carriers like mosquitoes)
What is a pathogen
A microorganism that causes a disease
How do viruses reproduce in the body
The virus infects a host cell and replicates itself many times by changing the DNA inside of the cell. The host cell then bursts and releases lots of the replicated virus cells which then infect other host cells.
How do bacteria reproduce in the body
Through binary fission where their offspring are identical to the parent cell with the the same genetic material
Symptoms of measles
A high fever and skin rashes
Effects of HIV
Weakens the immune system and leaves it more vulnerable to other infections and diseases
How is HIV transmitted
Through bodily fluids(unprotected sex) but also through cuts and injecting drugs using shared needles
Describe tobacco mosaic virus
Infects tobacco through contact with other plants(either naturally or by the hands of the farmers). It infects the chloroplasts and turns it from green to a yellow/white mosaic pattern. This reduces the plants ability to photosynthesize and grow properly. There is no cure for this disease.
How is Salmonella spread
By bacteria ingested in food or on food prepared in unhygienic conditions
Symptoms of salmonella
High fever, stomach ache , headache, loss of appetite and rashes
How is gonorrhoea transmitted
It is sexually transmitted
How can gonorrhoea spread be reduced
Not have anal or use protection
Cause of gonorrhoea
Caused by a bacterium
Symptoms of gonorrhoea
Burning pain when urinating and forms a yellow or green discharge
How is gonorrhoea treated
Through antibiotics
Describe rose black spot
Caused by a fungus that which infects roses and causes black/purple spots on the leaves. Reduces the plants ability to photosynthesize. Transmitted through the air of the water and also through contact of gardeners.
How does rose black spot spread
From leaf to leaf and plant to plant through the wind
How is malaria spread
Spread by mosquitoes which carry a protist which are found in higher temperature areas. Suck blood containing the protists from an infected person and pass the protist to other people they suck blood from.
Describe malaria and its causes ad preventions
Caused by mosquitoes that carry protists. Can cause fever, sweating, vomiting and headaches. No vaccination for malaria. Mosquito nets and insect repellents can prevent bites. Antimalarial drugs can prevent symptoms and infection.
How does skin defend you
It is a physical barrier that prevents microbes from entering.
Also produces anti-microbial secretions to destroy pathogenic bodies
How does respiratory system defend you
Nose is full of hairs to trap pathogens . Produces mucus that trap pathogens. Cells that live in the trachea and bronchi are covered in cilia that move the waft the pathogenic mucus to the back of the throat
How does digestive system defend you
Produces hydrochloric acid to destroy the micro-organisms in the mucus that you swallow.
How does immune system defend you
Your white blood cells try to destroy the pathogenic cells that get inside your bodies. Some white blood cells ingest the pathogens to digest and destroy them through phagocytosis
Role of white blood cells
To ingest micro organisms through phagocytosis, produce antibodies and produce antitoxins
Process of vaccination
Inject a dead or weakened pathogen. B cells will start producing antibodies and some of them will become memory B cells. If you are exposed to the pathogen, your body will remember how to fight of it and produce large amounts of antibodies very quickly.
What is herd immunity
If enough people are vaccinated, the disease cannot spread to those who aren’t. The whole population becomes protected. This is how to protect people with vulnerable immune systems
What can antibiotics treat
They can treat or prevent some types of bacterial infection. They kill bacteria and prevent them from reproducing and spreading
Explain the development of antibiotic resistance bacteria
A random mutation occurs in the DNA of individual bacterial cells. This protects the cell from the effects of the antibodies.
What are painkillers
They are chemicals which relieve the symptoms but do not kill the pathogen
Why are anti-viral drugs so hard to develop
This is because the virus infects a cell and hijacks the cell’s machinery in order to create more copies of itself. Destroying the virus will often mean destroying the cell that the virus is inside of.
Explain the stages of preclinical and clinical trials
Phase 1 - Testing the drug on a small number of healthy people to test for side effects
Phase 2 - Test it on a small number of people with the disease to see if the drug works
Phase 3 - Test it on a large number of people with the disease to see if it is cost effective and to compare with other drugs
What is a placebo
A substitute with no effect that looks like the drug. Patients often feel better/reassured when they are given treatment and say they feel better
What is double blind trials
Both the doctors nor the patients know if they are given the real or placebo drug. This avoids patient and scientist bias
How are monoclonal antibodies produced
They are produced by fusing antibodies ,which are taken from mice that have been stimulated to produce a certain type of antibody, with tumour cells which have been grown in tissue culture to produce hybridomas. These are then screened for antibody productions and then cloned. These monoclonal antibodies are then isolated for cultivation
Uses of monoclonal antibodies
Pregnancy test kits, Cancer diagnosis and treatment.
Can also bind to antigens on blood clots. Can also be attached to fluorescent dye that makes the process of locating the clot much easier and can speed up the amount of time to treat a patient.
How plant disease is detected and identified
Visual inspections, laboratory tests, microscopes and culture tests
Explain plant physical defence responses
Cellulose wall form a physical barrier between the cells and the pathogens, protecting it from infection
Explain chemical plant defence responses
Produce compounds that have anti-microbial properties that can defend the plant from disease causing agents.
Explain plant mechanical defence adaptations.
A impenetrable barrier of bark and waxy cuticle. Others include hard shells thorns and spines.
