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how nervous system adapted for a reflex action
receptor detects stimulus
receptor generate impulses
neurones conduct impulses
neurone A conducts impulses to spinal cord
neurone A = sensory neurone
synapse between neurones
chemical, neurotransmitters crosses synapse,
chemical stimulates impulses in neurone b
neurone B = relay neurone
neurone C = motor neurone
effector carries out response
muscles contract or gland secretes chemicals
why is it hard to treat someone with brain damage
limited ability to repair nervous tissue
any potential treatment could cause more or permanent damage
current understanding of brain function if limits
can’t treat parts in isolation
interpreting MRI scans can be complicated
ethical issues treating people who can’t consent
explain how each person can correct their eye defect with lenses
need a concave/divergent lens
concave lens diverge light rays, before they enter the eye
need convex/convergent lens
converge light rays before they enter the eye
how often to check germination experiment
days
hours too small to notice changes and weeks too long, so will miss growth
effect of using cotton wool instead of pad
cotton wool ball is uneven pad is even thickness
change the volume and distribution of water available to seedlings
explain reason for increase in oestrogen in first 14 days
needs to build up the uterus lining
high levels needed for LH to be released, and ovulation to occur
how can hormonal contraceptives be used to treat endometriosis
progesterone can be given to maintain high concentration
this prevents menstrual cycle
uterus cell build up can be reduced if progesterone keep high
high progesterone prevent uterus cell break don
brekaodn of cells but Ould not be Abe to leave the body in the same way that could cause symptoms
compare changes in blood glucose concentration, and then explain why
similarities
concentration rises and falls
highest concentration for both at 60 minutes
no effect seen for 30 minute
in diabetic person, no insulin being produced from pancrease
so excess glucose not being absorbed from the blood
method to test if diabetes cause high blood glucose level
test urine for glucose
define a habitat
non living parts of an ecosystem
why peat bog needs to be protected
disruption of food chain or migration if habitats removed
maintaining biodiversity is important as species can provide resources, like pollinators
draining lead can lead to more flooding and soil erosion
how to know if unsustainably getting
increased number of fish caught
number ff fish in the population able to breed is decreasgin
not enough fish are being left to reed to replace the fish being caugh
why intensive grow faster
cannot move freely, less energy loss, more food available, more energy for growth
disadvantage to intensive farming of fish
concern about animal welfare
cruel to tua
unethical or imoral
lac of spce
poorer favour, unlit, less od
why its diabetes have higher blood insulin concentration
cells absorb less glcose
so glucose concentration in blood remains high
which stimulates pancreas to release more inulin
if gene resistance to herbicide transfer to crop, what is the advantage of making crop plants resistant to herbicide
can use the red killer to kill weeds but not affect crops
so less competition for nutrient
so crops have higher yield
how to maintain rate of higher rate of reproduction of bacterial culture
add more sugar
amino acids
oxygen
increase temperature
remove toxins
stir the culture
two biological reason kidney transplant better
changes in concentration of urea are minised
so less chance of casein damage to body cells
not repeadtly puncturing skin
so less chance of infection, no need to take anti clotting drugs
reason hen culturing for
- several groups of cells scape off
- nutrient added to jelly
- hormones added to jellly
- plant cell keep in sterile conditions
- kept at 20c
so many plants can be reprodung
for making protein
so differentiation occurs
to prevent growth of microorganiss
so optimum growth
how spectacle lens fix long sightedness
converging lens
light rays refracted inwards more
light rays focused on retina
problem for light sighted
eyeball too shot
light focuses behind retina
form clear on nearer
ciliary muscles contract, so they have a smaller diametes
so suspensory ligaments loosen, so lens thickens
thicker lens is more convergent
light rays focused on retina
explain ho phototropism in plant shoot helped plant to survive
leaves receive more light
more photosntheis
produce more glucose
effect of light from one direction ontbhe growth of plant seedlings
several seedlings in each batch, measure heights of shoot, leave some in dark with light from one side, control it all round light,
same temp, water, soil type
after suitable time, record appears of seeldsin, remeasure height, detail of how bent shoots are,
calculate mean height increase
use protector to estimate angle of bedding
benefit of ions
potassium stronger root
phosphate, flowers or fruit growth
burget-
more cholesterol, narrowing of ratios,
more fat, narrowing of arties
carb, provide the energy
why experiment with quadrant may be incorrect
too few quadrants
sample may not be representative of the lan, if not placed radnomly
farming techniques, hy ore land is used and how it’s decreased biodiversity
increase population, farming crops for biofuels, peat use as compost and fuel, increase sue of pesticide
deforestation, monocultures, loss of hedgerows and habitat, change in migration, fertilise run off polluting water, use of positive reduce insects, damage food chain, more soil erosion
more carbon dioxide from machinery, more methane
climate change, acid rain and desertifation
how does iris cause change
muscle contraction
how does carbon dioxide increase, increase temperature
traps heat
why more water lost through skin when running
more sweating
as exercise release heat
need to cool the body
need to lose heat
need to maintain body temperature
why does breathing rate increase during running
more energy needed
so more aerobic respiration
so increase breathing rate
speciation works
isolation of different populations
habitat variation between lumber popluations
genetic variation or mutation
better adapted survive and pas on favourable alleles to offspring
eventually canon produce fertile offspring with other populations
how are they carried over
carried by favourable current on masses of vegetation
sewage, with organic matter and bacteria, causes fish to die
bacteria decay organic matter by digestion
and bacteria respire arobicdally
which lpwoers oxygen concenttion
so reduce energy supply, causes heat of fish
how is biomass lost
inedible parts
faeces
respiration
effect of moving or not
uneven distribution of hormone
even distribution of hormone in b
so top grows faster than bottom in root A
and equal growth in b
how to sexual reproduction useful
genetic variation
so better adapted to survie
and colonise new areas by seed dispersal
Manny offspring, so higher probability some will survive
experiment, light intensity affects number of dandelion plants that grown in a certain area,
placing of quadrats
large number of quadrants used
how randomness achieves, table fo radnom number
quadrants placed at coordinates
in each of two area of different light intensities
running through areas of differ light intensity
for each quadrant count number of dandelions and measure light intensit
compare data from different
large number of the quadrants used
Note 
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