infection and response Flashcards
what are pathogens?
pathogens are microorganisms that cause disease.
e.g- bacteria, virus, protists, fungi
how do bacteria cause disease?
they reproduce rapidly and produce toxins which damage cells
how do virus cause disease?
they reproduce rapidly INSIDE cell, causing cell to burst and get damaged
how do SOME fungi cause disease?
body is made from hyphae which grow and penetrate skin and the surface of plantsthey can also produce spores, spreading infection
how do protists cause disease?
through a vector which does not get infected with disease, only carries
examples of bacterial diseases?
- salmonella
- gonorrhea
examples of viral diseases?
- measles
- HIV
- Tobacco Mosaic Virus
example of fungal disease?
- rose black spot
example of protist disease?
- malaria
measles symptons, spread and prevention
- rash, fever and can be fatal
- inhalation of droplets from sneezes and coughs
- vaccinated when young
gonorrhea symptoms , spread and prevention
- pain when urinating, thick yellow/green discharge
- sexual contact
- contraception and antibiotics
salmonella symptoms, spread and prevention
- stomach aches, vomitting, diarrhoea
- bacteria ingested in food OR food prepared in unhygienicconditions
- in uk, poultry are vaccinated
HIV symptoms, spread and prevention
- flu-like, attack on immune cells -> damages immune system
- sexual contact AND exchange of bodily fluids i.e, blood- sharing needles
- contraception and controlled by antiretroviral drugs
TMV symptoms, spread, prevention
- discolouration of leaves, affected growth
- direct contact
- infected plant dug up and destroyed
malaria symptoms, spread, prevention
- episodes of fever and can be fatal
- through vector-mosquitoes (has most life cycle in)
- preventing mosquitoes breeding and mosquito repellent
rose black spot symptoms, spread, prevention
- purple/ black spots on leaves causing them to turn yellow and drop off, affecting growth
- spores in wind and water
- fungicides and/or remove and destroying affected leaves
how does TMV and rose black spots affect growth??
discolouration of leavesless chlorophyll (pigment + absorbs light) -> less photosynthesis ->less glucoseless respiration-> less energy -> less metabolic reactions -> less growth
process of phagocytosis
- phagocyte moves towards pathogen
- phagocyteengulfs pathogen
- phagocyte digests pathogen with digestive enzymes
what is antibody production?
lymphocytes produce proteins-> antibodies-> specific to surface of antigen on pathogen
what is antitoxin production?
type of antibodythat neutralises toxins produced by bacteria
How does the body defend itself from pathogens?
- skin barrier secretes anti microbial substances that kill pathogens
- nosehairs and mucus that trap particles
- trachea and bronchisecretes mucus to trap pathogenslined with cilia which wafts mucus up to be swallowed by throat
- stomachhydrochloric acid
how can the spread of disease be prevented?
- good hygiene
- isolating the infected
- vaccinations
- destroying vectors
how is disease spread?
- air
- water
- direct contact
vaccination
dead or weakened pathogen injected into body
white blood cells notice and produce antibodies specific to surface of antigens on pathogen to attack it
when infected with pathogen later - white blood cells recognise it and** produces antibodies at a faster rate in larger quantities**
what are the advantages of vaccinations?
- helped control many previous diseases
- epidemics can be prevented through heard immunity
what are the disadvantages of vaccinations?
- not always effective in providing immunity
- can cause bad reactions
difference between passive and active immunity?
active- antibodies provided from body
passive- antibodies provided from external source
difference between painkillers and antibiotics?
- painkillers (e.g aspirin)- relieve pain but doesnt kill pathogen- antibiotics (e.g. penicillin)- kills bacteria but doesnt kill virus- so not to damage body cells
How can bacteria become resistant to antibiotics?
mutations can occur during reproduction, and the resistant bacteria will survive and continue to reproduce- not dying from antibiotics
how to prevent development of resistant bacteria strains?
- stop overusing antibiotics
- finishing course of antibiotics to kill all bacteria
aspirin
- painkiller used to lower fever
- originated from a willow tree
digitalis
- treats heart conditions
- originated from foxgloves
pencillin
- alexander flemming was growing bacteria on plates and found mould growing that was free from bacteria- pencillium mould
what does the preclinical testing of drugs consist of?
testing on cells, tissues and live animalsFOR toxicity + effcacy + dosage (partly)
what does the clinical trials of drug testing consist of?
1st- healthy volunteers at a low dosage which is increased
2nd- patients with condition- double blind trial
what is a double blind trial?
where one group is given drug whereas other is given a placeboneither patient or doctor knows who has drug
- single blind- doctor knows
what is a placebo drug?
looks like drug but no active ingredients
what is efficacy?
whether the drug produces desired effect
reason for double blind trials?
reduces bias
why are they peer reviewed at the end?
to prevent false claims
process of monoclonal antibody production
- mouse injected with antigen to stimulate antibody production
- mouses’s lymphocytes taken out
- lymphocytes and tumour cell combined to make a hybridomacell
- Hybridoma cell can divide to produce clones, producing same antibody
- Antibodies can be collected and purified
what do the mouse’s lymphocytes and tumour cell combine to?
a hybridoma cell
Why is the lymphocyte combined with tumour cell?
Tumour cells don’t produce antibodies but divide rapidlyAntibodies can bind to anything specific
How does a pregnancy test work?
pregnant women’s urine contains hormone HCG
- urine travels up stick to reaction zone
- reaction zone- mobile HCG specific antibodies containing blue dye
- urine carries the dye and hormone to result window
- Result window- the bind toHCG specific antibodies
- Control window- antibodies complementary to reaction zone antibodies- to check test works
- IF PREGNANT- blue line
How can monoclonal antibodies be used to treat disease? i.e cancer
- cancer cells have antigens called tumour markers
- produce monoclonal antibodies in lab that bind to tumour markers to stimulate immune system to attack cell
- bind to receptors cells to stop dividing
- can used to transport anti- cancer drugs
how are monoclonal antibodies can be used in labs?
- for measure and monitor levels of hormones and other chemicals in blood or to detect pathogens
how can monoclonal antibodies be used in research?
to locate or identify specific molecules in a cell or tissue by binding them to fluorescent dye
disadvantagesof using monoclonal antibodies?
- side affects
- produced from mice lymphocytes
- expensive to develop
Why do plants need nitrate ions??
needed to make proteins- growth
lack- stunted growth
Why do plants need magnesium ions?
to make chlorophyll
lack- chlorosis- yellow leaves
Signs of plant disease?
7
- stunted growth
- spots on leaves
- areas of decay
- abnormal growths
- malformed stems or leaves-
- discolouration
- pests on leaves
How to identify the disease the plant has
- using gardening manual or website
- taking infected plant to laboratory
- using testing kits that identify the pathogen using monoclonal antibodies
Physical defences ofa plant
- waxy cuticle- barrier
- cell walls- barrier-
- layers of dead cells eg bark- stops pathogen entering
Chemical defences of a plant
- poisons to deter herbivores-
- antibacterial chemicals which kill bacteria
Mechanism defences of a plant
- thorns and hairs- painful to eat-
- droop/curl when touched- move away and move insects off
- mimcry to trick animalsdroop to look unhealthypatterns that look like butterfly eggs
species from ’ice plant family’ have stone/ pebble look
