disease Flashcards
infection and response, communicable and non-communicable disease
what are the 2 types of white blood cells?
- Phagocytes
- Lymphocytes
what are the jobs of white blood cells?
- Engulf pathogens
- Produce antibodies to neutralise the microbe
3.produce antidoxins to neutralise poisons produced by microbes
describe phagocytosis (4 steps)
- White blood cells (phagocyte) approaches virus
- Phagocyte surrounds virus
- Phagocyte engulfs virus
- Phagocyte absorb virus ready to start again
Is phagocytosis specific?
Non specific and occurs for all pathogens
what do lymphocytes produce? (2 things)
- Antibodies (y - shaped proteins) specific to an antigen
- antiroxins
What will antibodies do to pathogens?
(3 things)
- Cause cell lysis
- Attach to antigens preventing them entering the cells
- Cover pathogens and clump them together so they can be engulfed by a single phagocyte
what is the primary response?
*lag phase while population of lymphocytes increases
*rapid increase of antibody levels
*levels off as pathogens are destroyed
what is the secondary response
- no lag phase because the lymphocyte memory cells are already present
*extremely rapid rise in antibody levels
what is the difference between primary and secondary response?
*secondary response is QUICKER
*secondary response has a HIGHER peak in antibody concentration
why do pathogens make us feel ill?
realease toxins into our bodies
what do lymphocytes produce to neutralise toxins made by pathogens?
antitoxins that combine with each specific toxin to make a safe chemical
what is immunity?
when the same type of pathogen enters a body, lymphocyte cells recognise it and immediately make lots of antibodies tlo destroy the pathogen (so the body is immune to that disease)
what is vaccination?
when a small amount of an inactive or dead pathogen is introduced to the body so that the lymphocytes can have a primary response and make antibodies without the person actually being ill, so that when the same live pathogen infects you, your lymphocytes can immidiately make antibodies (have a secondary response)
what is herd immunity?
when a large proportion of the population is immune so it it is harder for the pathogen to reach unimmunized people leading to a resistance in the spread of an infectious disease
what are some issues with vaccines and vaccination initiatives?
- stops working if pathogen mutates
- side effects such as muscle and jointt aches or fevers
- allergies to vaccine ingredients
- expensive
- not all people or countries will want to participate, reducing effectiveness
- takes a long time to develop
a good vaccine must be …
(4 points)
- cheap to make
- easy to store and distribute
- safe
- have willing volounteers to be immunised and give the immunistion
what is a drug?
a chemical that alters how the body works
how do painkilllers work?
stop nerve impulses so you feel little or no pain (and other side effects)
what 2 natural drugs are common in painkillers
- willow bark eg aspirin
- poppies eg opiates
what are the 2 roles (and types) of medicine?
- cure the underlying illness eg antibiotics
- relieve symptoms eg painkillers
what do antibiotics do and how do they work?
- intefere with a pathogen’s metabolism
- slow bacterial growth long enough for the immune system to respond
- only work on BACTERIA and do not harm our own cells or other types of pathogens
what is antibiotic resistance?
- occurs through mutations of bacteria (errors when bacteria copies its DNA)
- means the antibiotic and antibodies for that bacteria no longer work
how does antibiotic resistance happen?
(4 steps)
- a non-resistant bacteria exists that divides by binary fission to create a population
- mutation occurs in one or more, making it resistant to the antibiotic
- the antibiotics kill most the bacteria but those with the resistance genes survive
- those bacteria that survive divide by binary fission unti lthere is a drug resistannt population
how can antibiotic resitance be avoided by farmers?
- agricultural use of antibiotics should be restricted
- instead, animals can be vaccinated
how can antibiotic resitance be avoided by the general public?
- handwashing
- vaccinations
- completing your course of antibiotics
what must all drugs be tested for?
(4 thing)
- effectiveness
- dosage
- stability (can it be stored for a period of time?
- safety
what stages are there for drug development?
(4 stages)
- preclinical testing - live tissue, then animals
clinical testing - phase 1 - healthy volounteers
- phase 2 - ill volounteers
- phase 3 - ill volounteers and long term effects
who and what is tested in phase 1 of drug development?
10-100 healthy volounteers, checking safety and dosage
who and what is tested in phase 2 of drug development?
200 - 400 ill volounteers,
looking for efficacy and side effects
who and what is tested in phase 3 of drug development?
3000+ volounteers with use of placebo and double blind trial
what is a placebo drug?
a treatment that doesn’t actually contain the drug
what is a double blind trial?
doctors and patients don’t know who is in the test group (taking the real drug) and who is in the control group (taking the placebo drug)
what are monoclonal antibodies?
mABs are antibodies that come from cells that are cloned from one cell
how are monoclonal antibodies made?
(5 steps)
- a mouse is injected with a specific antigen
- the mouse’s lymphocytes make specific antibodies that attach to the antigen
- these lymphocytes are extracted and combined with tumor cells
- this makes HYBRIDOMA cells which make the antibody and are able to divide indefinitely
- hybridoma cells are cloned to make many identical cells which make the same antibody rapidly
what are some uses of monoclonal antibodies?
- pregnancy/covid tests
- treating and detecting cancer
- identifying diseases
- locating blood clots
- testing for drugs
what are some issues with monoclonal antibodies?
- expensive and time consuming
- lots of side effects
- too specific (only treat one disease at a time)
- ethical issues (kills mice)
how do monoclonal antibodies work in blood tests?
scientists can label a monoclonal antibody with a coloured compound, which appears more saturated when more of the antigen/ antibody target is present
how do pregnancy tests work?
- pregnant women’s urine contains a hormone called hCG
- pregnancy tests contain monoclonal antibodies which bind to hCG
- when a pregnant women’s urine passes on the reaction zone of a pregnancy test, the mobile mAB bonds to the hCG and flows over to the result zone
- in this zone, there are dye-labelled hCG antibodies which turn coloured showing you are pregnant
- there is also a control zone to make sure the pregnancy test is working
how can mABs be used to treat cancer?
(3 ways)
- flourescent lables are attached to antibodies so help identify and diagnose cancerous cells
- deliver drugs directly to cancerous cells by detecting the specific antigen
- activates amd targets immune response to cancer cells
testing antibiotics - variables
required practical #2
independent - antibiotic used
dependent variable - bacterial growth
control variable - temperature, conditions, bacteria used
method for testing antibiotics
(8 steps)
required practical #2
- add 100μm of microbial culture to the agar gel plate with a sterile pipette(don’t fully open the plate to prevent other pathogens going into the agar plate)
- sterilise a spreader by dipping it in ethanol and passing it through a flame, hold it under the sterile umbrella whilst it cools
- use the spreader to spread the microbial culture around the plate
- sterilise forceps (step 2)
- use forceps to place antibiotic ring on the agar plate
- tape the agar plate partially shut, but not fully (aerobic conditions needed)
- incubate for at least 24hrs at room temperature (25C)
- measure the diameter of the clear area around the disc
why should you work aseptically?
required practical #2
to prevent contamination and growth of other pathogens such as fungi which would intefere with the experiment
what is health?
the state of physical and mental well-being
what will make someone more likely to suffer from infectious disease?
defects in the immune system
what can trigger asthma and allergies?
immune reactions originally caused by a pathogen
what can severe physical ill health lead to?
depression and other mental illness
what is measles?
a viral disease that causes a red skin rash and fever symptons, but can have serious complications like pneumonia and brain inflamation
how are measles spread?
droplets from infected people’s sneezes/ coughs
what is hiv?
- a virus spread by exchanging bodily fluids (eg blood or sex) which intially cause flu-like symptoms
- late stage hiv is known acquired immunodeficiency syndrome (AIDS)
what causes food poisoning and how?
salmonella bacteria produce toxins which cause food poisoning eg vomiting and diarrhoea
how can you contract salmonella?
eating food that has been contaminated
- by being prepared in unhygenic conditions
- by eating something that caught the disease whilst alive eg poultry
what is gonorrhoea ?
a bacteria passed through sexual contact (std)
symptoms of gonnorrhoea?
- pain when urinating
- thick yellow or green discharge from the vagina or penis
(treated with antibiotics)
what is malaria?
a disease caused by a protist, trasported by a vector (mosquitoes)
how can spread of malaria be reduced?
- reducing the amount of mosquitoes
- insectecides and mosquito nets
what are the first defences againts pathoghens in a human body? (7)
- skin
- nose hair
- mucosal membranes
- stomach acid
- tears
- eye lashes
- scabs
how does skin act as a first line of defence against pathoghens?
- different layers block micro-organisms
- dead epidermis constantly shedding
- sebaceous glands in skin produce acidic antimicrobial oils
how do nose hairs act as a first line of defence against pathoghens?
- trap solid particles that could contain pathogens in sticky layer of mucus
how do mucosal membranes protect act as a first line of defence against pathoghens?
- goblet cells produce mucos to trap particles containing pathogens
- cillia in trachea and bronchi waft mucus to back of throat where it can be swallowed
how does stomach acid act as a first line of defence against pathoghens?
- hydrochloric acid (HCl)
- very corrosive (pH 2) which can destroy cell walls of pathogens
what bacteria can survive in stomach acid?
helicobacter pylon
how do tears act as a first line of defence against pathoghens?
- has lysozyme
- high salt content to dry up microorganisms
- wash out microorganisms
how do eyelashes act as a first line of defence against pathoghens?
- act as a barrier which protects the eye
- trap dirt and microorganisms
what is lysozyme?
enzyme in tears, mucus, blood and saliva that break down bacterial walls
