2014 june Flashcards
give reasons why a shorter food chain passes on the greatest proportion of biomass and energy to humans (3)
✏️ shortest or fewest stages / transfers / (trophic) levels
✏️ less losses in waste / faeces / urine / CO2 / excretion
✏️ less loss in respiration / heat / movement
describe how animals and plants are adapted to survive in dry conditions such as deserts. for each adaptation that you give, describe how the adaptation helps the animal or plant to survive in dry conditions. go obtain full marks you should refer to both animals and plants (6)
animals:
✏️ change / decrease in surface area / example - reduces area from which sweat / water may be lost
✏️ hump with fat / fat stores - to convert to water (via respiration)
✏️ long eyelashes - to keep (windblown)
dust out of eyes
✏️ nocturnal / ‘keep out of the sun’ - reduce sweat loss (in heat of the day)
plants:
✏️ decrease in surface area or leaves are spikes - reduces water loss / transpiration / evaporation
✏️ long / wide spread / extensive roots - to absorb (more) water
✏️ fleshy / thick stem - to store water
suggest how dead plants decaying in a nest helps to keep the eggs warm for many weeks (3)
✏️ microorganisms
✏️ (microorganisms) respire
✏️ (respiration / decay / microorganisms) releases (thermal) energy / ‘heat’
megapode birds open and close the air vents of the nest at different times of the day. suggest reasons why it is necessary to open and close the air vents (3)
✏️ (opening) allows oxygen in
✏️ microorganisms / eggs need oxygen
✏️ oxygen needed for respiration
✏️ (opening) allows release of carbon dioxide (from
microorganisms / respiration / eggs)
✏️ (opening) allows energy / ‘heat’ to escape
✏️ (closing) retains energy / ‘heat’ if too cool / at night
✏️ (closing) retains moisture
The sex of a megapode bird that hatches from an egg depends on the temperature at which the egg was kept. use this information to suggest why it is important for megapode birds to control the temperature of their nests (1)
maintains sex balance, (survival of species depends on there being) males and females in population
apart from measles, which two other diseases does the MMR vaccine protect against? (1)
mumps & rubella / german measles
suggest one advantage to the population as a whole of children having the second MMR vaccination (1)
less chance of epidemic / pandemic OR less chance of spread of disease / measles / mumps / rubella
what does a vaccine contain? (1)
dead / inactive pathogens / viruses / bacteria
explain how a vaccination prevents infection (3)
✏️ white blood cells produce antibodies
✏️ antibodies produced rapidly (on re-infection) or response rapid (on re-infection)
✏️ these antibodies kill pathogens / viruses / bacteria
antibiotics can only be used to treat some infections. explain why antibiotics cannot be used to treat measles (2)
✏️ antibiotics don’t kill viruses
✏️ (because measles) virus / pathogen lives inside cells
why do antibiotics become less useful at treating an infection if the antibiotic is overused? (1)
(bacteria / pathogens) develop resistance (to antibiotic)
a nerve impulse passing along a relay neurone causes an impulse to be sent along another type of neurone, what is the name of this neuron? (1)
motor neuron
describe how information passes from the relay neurone to the motor neuron (3)
✏️ release of chemical (from relay neurone)
✏️ chemical crosses gap / junction / synapse
✏️ chemical attaches to motor neuron / next neurone (causing impulse)
what was the drug thalidomide originally developed to treat? (1)
idea of poor sleeping
soon after it was developed, thalidomide was found to be useful in treating another condition, what was this other condition? (1)
(for) morning sickness (in pregnant women)
describe one harmful effect of thalidomide (1)
limb abnormalities / defects
suggest why this harmful effect had not been detected during clinical drug trials on thalidomide (1)
drug not tested / trialled on pregnant animals / women
using a recreational drug may cause a person to become dependent on the drug. what happens in the body to make someone dependent on a drug? (1)
changes to chemical processes
graph question - some people think that some legal drugs should be made illegal, why (use info from graph)? (2)
✏️ dependency on (some) legal drugs is more than / equal to on (some) illegal drugs
✏️ example of a named legal drug for which dependency is equal to or greater than a named illegal drug
suggest one piece of information about legal drugs that would need to be considered before the classification of these drugs was changed (other than dependency on legal/illegal drugs) (1)
the harm it does / harmfulness or effect on health or side effects
use Darwin’s theory of natural selection to explain how the elephant’s trunk evolved from the Phiomia to the Elephant (4)
✏️ variation (in population) / mutation
✏️ longer nosed individuals get more food / leaves
✏️ (these) survivors breed (more)
✏️ pass on genes / alleles / DNA (for long nose)
use Lamarck’s theory to explain how the elephant’s trunk evolved from the Phiomia to the elephant (2)
✏️ phiomia / ancestor stretched its nose (during its lifetime) to reach food / leaves
✏️ passed on (stretched nose) to offspring
in the 1800s, many scientists could not decide whether Lamarck’s theory or Darwin’s theory was the right one. give two reasons why (2)
✏️ insufficient evidence / no proof
✏️ mechanism of inheritance not known (didn’t know about genes)
before the 1800s, many people had a different idea to explain where all the living things on earth came from. what idea was this? (1)
god made all living things / them
describe how scientists can transfer the gene from bacillus thuringiensis (which killls insects) to maize plants (3)
✏️ (gene) cut out
✏️ (gene / cut out) from (bacterial) chromosome / DNA
✏️ ref to enzymes (at any point)
✏️ (gene spliced) into maize chromosome / DNA
✏️ (gene added) at an early stage of development
would you advise farmers to grow GM maize plants?
justify your answer by giving advantages and disadvantages of growing GM maize plants. (4)
advantages:
✏️ less effort for farmer or less likely to harm farmer
✏️ (pesticide) always there or doesn’t wash away
✏️ less insects to eat crop / maize or carry disease
✏️ so greater crop production / yield
disadvantages:
✏️ (toxin) kills other insects
✏️ so (some) crops don’t get pollinated / (sexually) reproduce
✏️ possible harm when eaten by humans / animals
✏️ damage to food chains
✏️ gene may spread to other species
