Biology Paper 2 June 2019

1. ANo eating, tasting or inhaling substances in the laboratory
2. BWearing open sandals instead of closed shoes, to allow quick movement around the bench
3. CWorking alone without supervision, to save time during a practical
4. DMixing any two chemicals together to observe the reaction that occurs

1. ASand is thrown to smother the person, not the fire, which would not stop the flames from spreading
2. BSand cools the fire by absorbing its heat directly, the same way water lowers a fire's temperature
3. CSand is spread over the fire, depriving it of oxygen and dousing it
4. DSand reacts chemically with the flames to neutralise them, similar to a fire extinguisher's foam

Answer this when you sit the paper.

Answer this when you sit the paper.

1. ATo synthesise the cell wall surrounding the sperm, though sperm, like other animal cells, have no cell wall
2. BTo store food reserves for the developing embryo, a role instead carried out by the yolk in the egg cell
3. CTo produce energy required for the motility (swimming) of the sperm
4. DTo produce haemoglobin for oxygen transport, a role carried out by red blood cells, not sperm

Answer this when you sit the paper.

1. AThey bleach the fabric to remove colour from stains, a job done by bleach, not the enzymes in the powder
2. BThey increase the water temperature to dissolve stains, though enzymes work at warm, not heated, temperatures
3. CThey break down insoluble stain molecules into smaller soluble molecules that can be washed away
4. DThey coat stains in a protective layer to prevent spreading, rather than breaking them down chemically

Answer this when you sit the paper.

1. ALoud music dries out the auditory canal, causing wax build-up, rather than damaging cochlear receptor cells
2. BLoud music cools the eardrum, making it less flexible, though sound vibration does not change its temperature
3. CLoud vibrations can damage the ossicles and cochlea, damaging receptor cells and causing deafness
4. DLoud music raises blood pressure in the semicircular canals, though these canals control balance, not hearing

1. AGenetic (inherited) factors and environmental factors
2. BOnly the diet of the organism's parents, ignoring the genes passed on to the offspring
3. COnly the temperature at which the organism was born, ignoring the genes inherited from its parents
4. DOnly the age of the organism, since age alone does not account for differences between individuals

1. AIt results in offspring genetically identical to the mother, when selective breeding still mixes two parents' genes
2. BIt removes disease resistance from the offspring, when breeders instead select for resistant traits
3. CIt removes the need for the farmer to breed animals at all, when breeding is exactly what selection requires
4. DIt allows the farmer to select and breed animals or crops with desired features, improving yields

1. ADecomposers and detritus only
2. BHerbivores and carnivores only
3. CProducers and consumers
4. DPredators and prey only

1. ARoots hold soil particles together, reducing soil erosion and surface run-off
2. BIt increases the speed of surface water run-off, stripping topsoil rather than reducing erosion
3. CIt prevents water from percolating into the soil, causing waterlogging rather than reducing erosion
4. DIt removes microhabitats and reduces pest numbers, rather than binding the soil together with roots

1. AProducing electrical impulses for the nervous system, a role carried out by neurones, not water itself
2. BSynthesising proteins directly from amino acids, a process carried out by ribosomes, not water
3. CStoring genetic information for reproduction, a role carried out by DNA in the nucleus, not water
4. DActing as a solvent and transport medium, and regulating body temperature

1. AA large amount of heat is lost through evaporation of a small amount of water, cooling the body without much dehydration
2. BIt allows water to conduct electrical impulses along neurones, though nerve impulses are carried by ion movement, not water conducting electricity
3. CIt makes water a poor solvent, protecting cells from toxins, though water is in fact an excellent solvent
4. DIt allows water to freeze quickly, preserving tissues, though freezing actually ruptures cells with ice crystals

1. AParallel leaf venation and scattered vascular bundles
2. BFibrous or adventitious roots
3. CFlower parts arranged in threes
4. DTwo cotyledons in the seed and branched leaf venation

1. ACarbohydrates, for energy, though legumes are better known for their protein content
2. BFats, for energy and warmth, though legumes contain relatively little fat compared with protein
3. CRoughage, for smooth bowel movement, though this is a minor component compared with their protein
4. DProteins, for body building and tissue repair

1. AIt only affects aquatic organisms, not terrestrial ones, ignoring the habitat loss affecting land animals
2. BIt causes adverse weather and habitat loss, forcing migration and reducing biodiversity
3. CIt increases rainfall evenly across all regions, improving habitats, when rainfall instead becomes erratic
4. DIt has no effect on animal habitats, only on human agriculture, ignoring the habitat loss it causes

1. ARemoving legal restrictions on hunting, which would increase pressure on wildlife populations
2. BCreating game reserves and having legislation to discourage poaching
3. CClearing natural habitats to create farmland, which destroys the habitats wildlife depends on
4. DEncouraging unrestricted use of wildlife products, which would increase poaching pressure

1. AAlcohol increases the foetus's birth weight significantly, though exposure reduces birth weight instead
2. BAlcohol crosses the placenta and can cause foetal alcohol syndrome, retarding foetal growth
3. CAlcohol strengthens the placenta, protecting the foetus, though alcohol actually harms placental function
4. DAlcohol has no effect on the foetus, only on the mother, though alcohol readily crosses the placenta

1. AViruses produce their own antibiotics to protect themselves, though antibiotic production is a bacterial/fungal trait
2. BAntibiotics target bacterial cell walls/metabolism, but viruses lack a cell wall and their own metabolism
3. CViruses are too large for antibiotics to penetrate, though viruses are far smaller than bacteria, not larger
4. DAntibiotics work at body temperatures below normal, though antibiotic activity does not depend on temperature

1. AIt is caused by a pathogen and can be transmitted between people
2. BIt cannot be transmitted from person to person, which is a feature of non-infectious disease
3. CCommunity hygiene has no effect on its occurrence, though hygiene strongly affects pathogen spread
4. DIt is caused by inheritance or diet, which describes a non-infectious disease, not one caused by a pathogen

1. ADiscouraging contact tracing of infected individuals, which lets infections spread further undetected
2. BProper use of condoms and early treatment of infected individuals
3. CDelaying treatment until symptoms become severe, which allows more time for the infection to spread
4. DAvoiding all forms of sex education, which leaves people less informed about safe practices

1. AWell-adapted organisms survive and reproduce, passing on favourable alleles, changing the gene pool over time
2. BAll organisms in a population survive and reproduce equally, so no allele becomes more common over time
3. CAlleles do not change in frequency within a population over time, so the gene pool stays exactly the same
4. DOnly the youngest members of a species can reproduce, regardless of how well-adapted an individual is

1. ATo reduce the number of animals a farmer owns, freeing up land and feed for other farm activities
2. BTo remove genetic variation among the animals, producing an identical herd with no diversity at all
3. CTo increase the animals' susceptibility to disease, weakening the herd's ability to resist infection
4. DTo improve the quality and quantity of products such as meat or milk, and to meet market demand