Topic 4: Biodiversity and Natural Resources Part 2 Flashcards
outline the first drug trial
William Withering’s digitalis soup
Dropsy aka odoema is when fluid accumulates in body tissue and leads to drowning as it fills lungs; it involves having a fast/irregular heartbeat
foxgloves are a plant poisonous to plants+animals that affects heart rate, causes diarrhoea and vomiting etc.
Withering met Mrs Hutton who had dropsy and she was doing a special tea she made and was cured the next time h saw her
she sold him the recipe and he found that foxglove was one of the tea’s herbs
he tried treating his patient with it and the 1st recovered bu the 2nd almost died
he later did almost 160 trials and realised the importance of dose on the drug’s success
he used a standard procedure to calculate dose; he increased it until diarrhoea and vomiting was induced before decreasing it to find optimal dosage
describe drug development
total journey + testing takes 10-12 years
- potential new substances are analysed and the active ingredient is identified so that it can be copied and manufactured synthetically
- chemical structure is varied slightly to see if the medicinal effect is increased
- many drugs nowadays are discovered through computer modelling different structures
what is the placebo affect
when patients receiving the placebo show improvement even though the placebo does not contain any active ingredients
what is the purpose of double blind trials and placebos
they increase validity
outline double blind trials
they are usually used in phase 2 and 3 clinical trials
neither the doctor or the patient knows who is given the placebo ( or the version currently on the market) or the new drug
this reduces bias because patient/doctor attitudes can’t influence results
how can plant fibres improve sustainability
Using them to make things like ropes and fabric is more sustainable than using oil-based plastics
Less fossil fuels are used and plants can be replanted for the next generation
Plant fibres are biodegradable, unlike most oil-based plastics, so these fibres can be broken down by microbes to minimise environmental pollution
Extracting and processing oil is an expensive and difficult procedure compared to growing and processing plants, making plant-based products easier and cheaper to produce in developing countries
But, the ropes made from plant fibres are typically not as strong as plastic ones
Starch and Sustainability
what are some uses of plant fibres and why
rope, clothing, floor coverings, paper
because they’re flexible, long, thin, strong
the fibres can be added to other materials to form biocomposites which re renewable, biodegradable and are often easier/safer to handle than composited with just artificial fibres
outline the stages of drug testing
pre-clinical testing:
animal and lab studies on cells and tissues to assess the safety and effectiveness of compounds
clinical trial phase 1:
small healthy volunteer group are given the drug to see if it is absorbed, distributed and excreted by the body by the predicted mechanisms
clinical trial phase 2:
a small group of people with the disease are treated to look at effectiveness
clinical trials phase 3:
large group is split into 2, half with placebo and half with drug
double-blind randomised control trial
if results are statistically significant the drug can be licensed and marketed
after licensing:
trials continue, collecting data on safety and effectiveness
why do plants need magnesium ions and how is a deficiency presented
for chlorophyll production, therefore vital for photosynthesis
a deficiency limits chlorophyll production so there can be a lack of carbohydrates due to less photosynthesis and plant leaves may be small and yellow
why do plants need nitrate ions
to synthesise DNA, proteins like enzymes and chlorophyll
these are essential for plant growth and fruit +/ seed production
why do plants need calcium ions
they form cell wall components and so are required for proper growth
how would a vaccine’s clinical trials be conducted
give the vaccine to a small group of healthy volunteers to test or side effects
then test for antibody presence
give vaccine to people at risk of contracting the disease
monitor the number if people that develop the corresponding disease post vaccination
describe aseptic technique when using bacterial cultures
working next to a Bunsen burner to provide a convection current
sterilising work surfaces
flame equipment to sterilise
limiting time that containers are kept open
devise a procedure to look at the antimicrobial properties of various plant extracts
- use a sterile pipette to transfer bacteria from a nutrient broth to an agar plate, spread it around using a sterile plastic spreader and cover the plate with a lid
- prepare extracts from plants you want to test: dry and grind each plant, then soak in ethanol (extracts antimicrobial substances bc their soluble in it) and filter off the liquid
- dip equally sized sterile paper discs into the extracts using sterile forceps, they should all be left for 2mins + a control disc in ethanol
- place discs on agar and space them out, tape on the lid tightly and invert, incubate at around 25˚C for 24-48 hours
- measure and calculate the Zone of Inhibition
devise an investigation into the effect of different calcium ion concentrations on plants
- make up nutrient broths with all essential minerals, but vary calcium on concentration; have a high, medium and low of calcium ion
- split 9 test tubes into 3 groups and fill each group with one of the broths and label
- take 9 same age seedlings of the same plant eg. germinated mung beans. measure and record the mass of each, place into a test tube so that the root is in the nutrient broth, support with cotton wool
- cover outside of tube with aluminium foil so no light can get to the nutrient broth and promote algae growth etc.
- place all tubs near the same light source and leave for 2 weeks, top up broth so roots stay suspended
- remove plants and blot dry, measure and record new mass and calculate mean change in mass of each plant for each broth; note down other visual differences
if doing different nutrients: need 2 controls, 1 with none and 1 with all
devise an investigation to look at different parts of plant stems
- use a scalpel to cut a cross section of the stem as thinly as possible
- use tweezers to place the cut sections in water until you use them
- transfer each section to a dish containing a Toluidine Blue O stain and leave for 1 minute, TBO stains lignin blue green and will show positions of xylem vessels and sclerenchyma fibres, phloem cells and the rest of the tissue should appear pinkish purple
- rinse off sections in water and mount one onto a slide
- place slide under microscope and adjust to get a clear image of the sample, making a clear drawing
how are ions transported in a plant
they’re transported in the xylem in solution
how is drug testing today different to the drug testing used back in will’s day
safer
- we test on cells/animals before humans
- testing is regulated by legislation
more valid
- compare with placebo
- use double-blind sometimes
more reliable
- test more people
- analyse results to statistically
what temperature should i incubate my agar plate at
25 degrees celsius
anything from 20 to 30
why are seeds dried before storage
it prevents germination which extends storage time
why is seed conservation important
it prevents the extinction of a species
it allows the conservation of species with potential medicinal properties
allows for reintroduction of the species in the future
why do we use a placebo
to allow comparison between x and y
how do you describe putting bacteria on agar plates
produce bacterial lawn
what are factors to consider when comparing types of fibres
biodegradability/not
renewability/not —> will it be available for the future gens or will it run out
