Infection and Response Flashcards
Describe bacteria
- once inside the human body, reproduces very rapidly
- can release harmful chemicals called toxins
- toxins damage tissues and make us feel ill
Describe viruses
- cannot reproduce by themselves
- can only reproduce inside a host cell
- very damaging to the cell
- when the virus leaves the cell, it can cause the cell to burst open and die
How are pathogens spread
- air e.g. water droplets sneezing and coughing
- directly through water like cholera
- direct contact between individuals
How to prevent spread?
- clean drinking water
- washing hands
- condom during intercouse
- vaccination
- isolation
Symptoms, spread, effects and prevention of measles
symptoms
- fever
- a red skin rash 3 days after
spread by:
-droplets when an infected person sneezes or coughs
effects:
-can cause damage to the brain and breathing system
prevention:
-children should be vaccinated very young
Symptoms, treatment, transmission and prevention of HIV
symptoms:
- flu like illness which usually disappears after 1-2 weeks
- virus attacks the rest fo the immune system, damaging it over time severely
- patient becomes unable to fight off other infections and cancer cells
- this is called AIDS
Treatment:
- antiretroviral drugs stop the virus from multiplying in the patient so it doesn’t damage the immune system
- they will not develop AIDS and are able to live a normal life
Transmission:
- exchange of bodily fluids between humans
- sharing infected needles
Symptoms, transmission and prevention of salmonella.
symptoms:
- fever
- abdominal cramps
- vomitting
- diarrhoea
transmission:
- eating infected food that is prepared in unhygenic conditions
- bacteria secrete toxins that cause the symptoms
prevention:
- cook meat thoroughly
- vaccinate chickens
Gonorrhoea symptoms, prevention and treatment
symptoms:
thick green/yellow discharge from the penis or vagina
pain when urinating
treatment:
- antibiotics (penicillin)
- however antibiotic resistant strains are now common
prevention:
- use condoms
- get tested if you have unprotected sex
What is a protist?
- single celled eukaryotes
- often transferred to an organism by a vector
Symptoms and preventing malaria
How is malaria spread?
symptoms:
-repeated bolts of fever
prevention:
- stop them breeding by draining areas with still water
- spray areas of still water with insecticide
- sleep under a mosquito net sprayed with insecticide
how is it spread?
- infected person is bitten by a mosquito
- the malaria pathogen passes into the mosquito
- now it bites into another person and passes it into them
How does the skin prevent pathogens from entering the body?
- forms protective layer covering the body
- outer layer consists of dead cells and is difficult for pathogens to penetrate
- prodeces sebum which kills bacteria
- when it is damaged, it scabs over to prevent pathogens from entering
How does the nose prevent pathogens from entering the body?
-contains hair and mucus which traps pathogens before they enter the breathing system
How do the lungs prevent pathogens from entering the body?
- trachea and the bronchi are covered with tiny hairs called cilia
- cilia is covered in mucus which traps pathogens
- now wafts the mucus upwards towards the throat where it is swallowed into the stomach
How does the stomach prevent pathogens from attacking the body?
- contains hydrochloric acid
- kills pathogens before the go further into the digestive system
What does the immune system do?
Destroys pathogens and any pathogens they produce.
Explain phagocytosis
- WBC detects chemicals released from the pathogen and moves towards it
- WBC then ingests the pathogens
- the WBC uses enzymes to destroy the pathogens
What are antibodies and how do they work?
- protein molecules produced by the WBCs
- the antibodies stick to the pathogens
- triggers the pathogens to be destroyed
- extremely specific
- will not protect you against any other pathogen
- remain in the blood for a very long time
How do antitoxins work?
- WBCs produce these
- they stick to toxin molecules and prevent them from damaging cells
How does a vaccination work?
- introduce small quantities of a dead/weakened pathogen into the body
- won’t lead to disease
- WBCs are now stimulated to produce antibodies against it
- WBC divides by mitosis to produce lots of copies of itself
- they can stay in the blood for decades
- if the same pathogen enters, the WBCs can produce antibodies quickly, preventing infection
What is herd immunity?
- important that many people get vaccinated
- if enough people are, it protects unvaccinated people
- there won’t be anyone around the unvaccinated person that can pass the pathogen on
Why is it difficult to develop drugs that kill viruses?
- viruses live and reproduce inside human cells
- so the drugs could damage the body’s cells and tissues
What do lymphocytes produce antibodies against?
Antigens
explain the monoclonal anitbody mouse thing
- inject a mouse with antigen
- lymphocytes will produce antibodies against it
- collect the lymphocytes from the mouse
- fuse the lymphoyctes with the tumour cell
- tumour cells are very good at dividing by mitosis
- hybridoma cell produced
- these can produce antibodies and divide by mitosis
- select a single hybridoma producing the antibody we want
- hybridoma divides by mitosis to form a clone of identical cells
- antibodies produced are all identical
How are monoclonal antibodies used in pregnancy testing?
- detect a specific hormone
- which is produced by the placenta of the developing fetus
- cheap and easy to use
- simply urinate and look for a reaction
- highly accurate
How are monoclonal antibodies used in lab testing?
- measure the level of hormones in blood
- we can use them to detect pathpgens in the blood
- completely specific to what they are looking for
How do monoclonal antibodies work?
They are produced from a single clone of identical hybridoma cells.
Monoclonal antibodies are specific to a single binding site on one protein antigen.
We can produced monoclonal antibodies against any antigen we want.
How are monoclonal antibodies used to locate specific molecules in a cell or tissue?
The monoclonal antibodies are attached to fluorescent dyes.
The antibodies then stick to specific molecules within the cell and allow us to see their locations.
How are monoclonal antibodies used to locate specific molecules in a cell or tissue?
The monoclonal antibodies are attached to fluorescent dyes.
The antibodies then stick to specific molecules within the cell and allow us to see their locations.
How do monoclonal antibodies prevent cancer growth?
- antibodies can be made specific to the cancer cells
- they attach a radioactive substance of a toxic drug to the antibody
- when injected into the blood , it attaches to cancer cells
- the substance/toxic drug stops the cancer cells from growing and dividing
