B3 Flashcards
what are the different ways pathogens can be spread
Water
Air
Direct contact
How can pathogens be spread by water
You can pick up the pathogens by consuming or bathing in dirty water
You can spread the pathogens by drinking contaminated water
How can pathogens be spread by air
Pathogens can be carried by the air in droplets when you cough and sneeze and they can be breathed in
How can pathogens be spread by direct contact
Can be picked up and spread by touching contaminated surfaces (including skin)
Examples of viral diseases
Measles
HIV
what is measles
what: a viral disease spread by droplets of an infected persons cough or sneeze
issues: if there are complications, can be serious
symptoms: red skin rash, fever
treat: vaccinations against virus usually done at youth
What is HIV
what: virus spread by sexual contact or by exchanging bodily fluids
issues: attacks immune cells, if badly damaged then body can’t fight other infections (aids/late stage)
symptoms: initial symptoms are flu like
treat: can be controlled with antiretroviral drugs to stop virus from replicating
Examples of bacterial diseases
Salmonella
Gonorrhoea
What is salmonella
what: type of bacteria causing food poisoning
issues: food poisoning if contaminated food is consumed
symptoms: fever, stomach cramps, vomiting, diarrhoea
treat: most poultry is given vaccinations to control spread of disease
what is gonorrhoea
what: sexually transmitted disease
Issue: originally treated with penicillin but it’s more difficult due to antibiotic restraint
symptoms: pain while urinating, thick yellow or green discharge
treat: use condoms to prevent spread, use antibiotics to treat
give an example of a protist disease
Malaria
What is malaria
what: disease of which mosquitoes are the vector by feeding on infected animals and passing on
issue: can be fatal
symptoms: repeating fevers
treat: stopping mosquitoes breeding to prevent spread,use insecticides and mosquito repellent
how is the skin a defence system
- forms a protective, outer layer of skin on the body which consists of dead cells and is difficult for pathogens to penetrate through
- secretes antimicrobial substances as well as sebum which can kill bacteria
- scabs form over wounds to prevent pathogens from entering the body
how does the stomach act as a defence system
- contains hydrochloric acid which kills pathogens before they can make it further down into the digestive system
How is the nose a defence system
- contains hairs and mucus which trap particles that could contain pathogens
- this prevents the pathogens from entering the breathing system
How is the trachea and bronchi a defence system
- secrete mucus to trap pathogens
- contain cilia which waft the mucus up to the back of the throat where it can be swallowed
How does the immune system act as a defence system
- destroys pathogens and any toxins the produce
- protects us in case the same type of pathogen invaded us again in future
explain phagocytosis
- once the phagocyte (wbc) detects a foreign cell, it engulfs the pathogen
- it then uses enzymes to digest and destroy the cell
Explain the line of attack when antibodies are produced
- Once in contact with forge in cells, Lymphocytes (wbc) produce y-shaped proteins called antibodies which bind to invading cells so that they can be destroyed
- the antibodies are specific and will only bind to its specific antigen
- they are rapidly produced once made and are carried around the body
What are memory lymphocytes
- produce the same antibodies of an infection we have previously had in case we catch it again.
- the antibodies will be produced rapidly and so the person will naturally become immune to the pathogen
Explain the line of attack whe antitoxins are produced
- white blood cells produce antitoxins which stick te toxins molecules produced by invading cells and prevent them from damaging cells
What is the tobacco mosaic virus
what - virus that affects many species of plants
issue - discolouration means plants can’t carry out photosynthesis as well and leads to stunt growth
symptoms - causes mosaic pattern on leaves and discolouration
What is rose black spot disease
what - fungal disease that affects plants
issue - causes rate of photosynthesis to fall which then reduces rate of growth
Symptoms - development of black or purple spots on leaves
treat - spray plant with chemicals which can kill fungi or/and remove infected leaves and destroy them.
what is the process of vaccination
- inactive forms of a pathogen which carry antigens are injected into your body causing it to produce antibodies to attack them
- the wbc undergoes mitosis and multiplies to produce more antibodies
- if a live pathogens of the same type enter the body, wbcs can rapidly produce the antibodies needed to kill the pathogen which prevents infection
what are the pros of vaccinations
- Helps control many communicable diseases
- Epidemics can be prevented if a large percent of population is vaccinated
What is herd community
where that is most people are vaccinated, the unvaccinated are unlikely to catch the disease as there are fewer people to catch it from
What are the cons of vaccination
- Don’t always work
- Bad reactions to vaccines can happen
What was the first antibiotic discovered
Penicillin
what are antibiotics
drug that kills infective bacteria inside the body without harming cells
What is antibiotic resistance
where bacteria mutate leading to them becoming resistant to antibiotics
when treated only the non-resistant bacteria will be killed however the surviving restraint can reproduce and the population of the restraint will increase
What are painkillers
drugs that relieve pain
can on,y reduce symptoms
why is it difficult to develop drugs to kill viruses
viruses live and reproduce inside human body cells so it’s difficult to kill the viruses without also damaging body cells and tissues
What is aspirin and where did it develop from
A painkiller that lowers fever
developed from the willow tree
What is digitalis and where did it develop from
Used to treat heart conditions
Developed fromnfoxglove plant
What is penicillin and where did it develop from
Antibiotic
Originated from penicillin fungus
What is the pre-clinical process of drug testing
stage 1: testing drug on cells and tissue for toxicity and efficacy
stage 2: testing on small mammals for toxicity and efficacy
Why does we test the drug on small mammals
They have a similar organ system to humans
What is the clinical process of drug testing (stage 3)
Phase 1: very low dosage of drug given to healthy volunteers to see if it’s safe for humans
Phase 2: drug tested on a small group of patients to find optimal dosage
Phase 3: drug tested on a large group of patients
What is the optimal dosage
Best dose with minimal side effects
What is the post-clinical process of drug testing
Stage 4: drug is not published until they have been through data analysis and peer review
What is peer review
When other scientists check that the work is valid to prevent false claims
What are placebos
Fake version of the real drug which is ineffective
How do we use placebos to test drugs
- Patients are randomly put into two groups
- One group is given the new drug whilst the other is given a placebo without knowing who received what
- This is done so that the doctor can see the actual difference of the drug
What is the placebo effect
When the patient expects the treatment to work so they feel better
What is the double blind trial
When both the doctor and the patients don’t know who is receiving the drug and who is receiving the placebo
Why is the double blind trial done
To prevent any bias towards the patients or the symptoms and change
How are monoclonal antibodies produced
- A mouse is injected with a specific antigen which causes the lymphocytes to produce antibodies against the antigens
- The lymphocytes are then collected from the mouse
3.the lymphocytes are then fused with tumour cells to produce a hybridoma cell - Now a single clone of hybridoma cells can be extracted to allow to rapidly divide by mitosis
The antibodies produced from the hybridoma cells are identical which are called monoclonal antibodies - A large amount of these monoclonal antibodies can then be collected and purified
What are monoclonal antibodies
They are produced from a single clone of antibodies
Meaning they are specific to one binding site on one antigen which is beneficial as they can target a specific chemical or cell in the body, giving them a number of uses
How are monoclonal antibodies used in pregnancy tests
Used to detect a specific hormone which is called hcg which is produced by the placenta of developing fetus and is only present in the urine of pregnant women
How do pregnancy tests work if the woman is pregnant
- The part of the stick of which the urine goes has some antibodies to hcg with blue beads attached
- The test strip has some more antibodies stuck onto it
- If you are pregnant
- the hormone binds to the antibodies on the blue beads
- the urine moves up the stick, carrying the hormone and the beads
- the beads and the hormone bind to the antibodies on the strip so the blue beads get stuck on the strip, turning it blue
How do pregnancy tests work if the woman is not pregnant
- The part of the stick of which the urine goes has some antibodies to hcg with blue beads attached
- The test strip has some more antibodies stuck onto it
- If you aren’t pregnant
- the urine will still move up the stick, carrying the fluorescent dye
- however there is nothing to stick to the fluorescent dye onto the test strip so it does not go blue
How are monoclonal antibodies used in the lab
- can be used to bind hormones and other chemicals in blood to measure their levels
- can be used to test blood samples for certain pathogens
- to locate specific molecules on a cell or in a tissue
How are monoclonal antibodies used in the lab
- can be used to bind to hormones or other chemicals in blood to measure their levels
- can also be used to test blood samples for certain pathogens
- can be used to locate specific molecules on a cell or in a tissue
How can monoclonal antibodies be used for location
- First the specific monoclonal antibodies are made that will bind to the specific molecule needed
- The antibodies are then bound to fluorescent due
- If the molecules needed are presented in the sample then monoclonal antibodies will attach to them and they can be detected using the dye
How are monoclonal antibodies used to treat disease
- An anti cancer drug can be attached to the monoclonal antibodies
- The antibodies are given to the patient through a drip
- The antibodies target the specific cancer cells because they only bind to tumour markers
- The drug kills the cancer cells but doesn’t kill any normal body cells near the tumour
What are tumour markers
Antigens that are on the cell membrane of cancer cells but aren’t found on any other cells
What is an anti cancer drug
A radioactive substance, toxic drug or chemical that stops cancer cells from growing and dividing
What are the problems with using monoclonal antibodies
They cause more side effects that originally expected eg. Fever vomiting and low blood pressure
what are the common signs that a plant has a disease
- Stunned growth
- Spots on leaves
- Patches of decay
- Abnormal growth
- Malformed stems or leaves
- Discolouration
What are different ways you can identify the signs of a disease
- Using a gardening manual or website
- Taking infected plant to a laboratory
- Using testing kits to identify the pathogen using monoclonal antibodies
What does a nitrate deficiency cause in plants
Nitrates are needed to make proteins and therefore growth so a lack of nitrate causes stunned growth
What does a magnesium deficiency cause for plants
Magnesium ions are needed to make chlorophyll which is needed for photosynthesis.
A lack of magnesium means the plant will suffer from chlorosis and have yellow leaves
What are some physical defences of plants
- waxy cuticle
- cell wall
- bark
How is the waxy cuticle a physical barrier
The waxy cuticle provides a barrier to stop pathogens from entering
How are cell walls a physical barrier
Cell walls are made from cellulose and act as a physical barrier to the pathogen that pass through the waxy cuticle
How is bark a physical barrier
Like bark, plants have layers of dead cell around their stem which acts as a barrier, preventing pathogens from entering.
What are some examples of chemical defences for plants
- antibacterial chemicals
- production of poison
How are antibacterial chemicals a chemical defence
The antibacterial chemicals kill bacteria
How is production of poisons a chemical defence
Poisons can deter herbivores
What are some examples of mechanical defences for plants
- thorns and hairs
- drooping/curling
- mimicry
How are thorns and hair a mechanical defence
They stop animals from touching and eating them
How is drooping/curling a mechanical defence
by drooping/curling when something touches them, they can prevent themselves from being eaten by knocking insects off themselves and moving away from things
How is mimicry a mechanical defence
Mimicry prevents other organisms from laying eggs, eating, or coming close to the plant.
