biology paper 2 wrong

how nervous system adapted for a reflex action

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