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60 Cards in this Set
- Front
- Back
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What is dysentery caused by ? |
- A bacterium |
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How can a housefly cause a person to be infected with dysentery ? |
- Housefly carries a pathogen - housefly lands on contaminated faeces/animal waste - transfers dysentery /bacteriaonto food - infected food eaten |
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How can a chemical defence mechanism reduce the chances of contracting dysentery ? |
- Hydrochloric acid - in stomach - kills bacteria/ dysentry |
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Explain how the Anopheles mosquito can spread the disease malaria.
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- mosquito is a vector
- carriesprotozoan/Plasmodium - pierces skin - transfers(protozoan/Plasmodium) to blood |
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Euglena is unusual because it is both heterotrophic and autotrophic. Explain how this helps Euglena to survive.
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- autotrophs can make theirown food using sunlight
- heterotrophs eat otherfood - Euglena can makecarbohydrates and/or eatcarbohydrates - so are able to survive indifferent environments /survive in changingenvironments |
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How can scientists validate discoveries ? |
- publish findings inscientific journals
- use the peer reviewprocess - attend scientificconferences |
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How does positive gravitropism in root cells occur? |
- auxin
- on the underside ofthe plant root - inhibits the elongation of rootcells on the underside of theroot - cells on upper side continue toelongate - making the root grow downwards towards gravity |
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Why is positive gravitropism an advantage? |
- it helps to anchor the plant and make it stable - the roots are further down so can reach more water/more nutrients |
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What is the role of the sweat gland in thermoregulation ? |
- the sweat gland releases water /sweat onto the surface of theskin
- the water evaporates - by removing heat from thesurface of the skin / heat energylost as latent heat |
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Explain why the muscle attached to the hair follicle is important when aperson starts to feel cold. |
- the muscle raises thehair - this trapsa layer of air next to thesurface of the skin - which acts as an insulator - causing more heat to be retainedin the body |
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What is homeostatsis? |
The name given to the maintenece of a contstant internal environment |
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Explain why the temperature of the human body needs to be maintained at 37 °C. |
- this is the optimum temperature -involving enzymes - for chemical reactions in thebody /metabolic reactions in body e.g digestion - denaturation occurs at highertemperatures / at lowertemperatures reactions areslower |
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Explain why reptiles lie in sunlight for long periods of time. |
- reptiles are poikilothermic /ectothermic - they cannot generate heat tomaintain their own bodytemperature so they use the enironnment to conrol body temperature - so use the sun to warm theirbodies - so that chemical reactions can occur quickly |
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Describe how the level of water pollution and air pollution can be assessed usingliving organisms. (6 marks - first half - water pollution)
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Water pollution – polluted
- bloodworms / sludgeworms - a lot of them signifies high water pollution - they can survive only low oxygenated waters therefore polluted waters Water pollution – clean - freshwater shrimp / stonefly larvae - a lot fo them signifies low water pollution - they can only survive in areas of high oxygen therefore unpolluted waters |
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Describe how the level of water pollution and air pollution can be assessed using living organisms. (6 marks - second half - air pollution) |
Air pollution - blackspot fungus found on roses
- blackspot fungus is killed by the presence of sulfur dioxide thatwould be found in polluted air, therfore only grows in unpolluted air. - lichen – certain types of lichen can survive in pollutedareas – so depending on the type of lichen found will beused to assess the pollution level of air |
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Some rats have a mutation which enables them to eat the rat poison Warfarin andsurvive. Suggest how the use of Warfarin could lead to an increase in the number of ratswith this mutation. |
- rats with the mutationsurvive to reproduce, whilst those who aren't resistant die - pass on the allele whichmakes the offspringresistant to warfarin |
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Explain how shivering can help a person regulate their body temperature. |
- muscles contract - producing heat - warming the body |
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Explain how smoking tobacco can cause cancer |
- tobacco contain tar - tar is a carcinogen - leads to mutations in cells |
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What type of drug is caffeine ? |
A stimulant |
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Describe the effect caffeine can have on the human body. |
- affects the CNS / nerves - reactions speed up / decreasereaction times - reference to synapse /neurotransmitters |
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Name the characteristics of the kingdom Plantae |
- photosynthesise - they feed autotrophically - have chlorophyll - have cell walls made of cellulose - multicellular |
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Vertebrates are members of what phylum? |
- Chordata |
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Name three structure vertebrates use to absorb oxygen from htier surroundings? |
- lungs - gills - skin |
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State the type of pathogen that causes cholera |
- bacteria |
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How is cholera spread? |
- In water |
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Suggest two reasons for an increase in cholera |
- world travel /migration - no access to clean water - resistant bacteria |
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Explain how the physical barriers of the body can help to prevent infection bypathogens. |
- skin prevents the entry -scab formation on skinprevents entry into wound - cilia traps pathogens / moves pathogens upwards -mucus traps pathogens |
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State the names of chemicals that can be used to control infection. |
- antibiotics - antifungals - antibacterial - antiseptic |
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Name the organ that releases insulin to regulate blood glucose concentrations. |
The pancreas |
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Explain how growth hormones cause phototropism and gravitropism in plants (6 marks - first half - phototrophism) |
- auxin / gibberellin is a plant growth hormone - phototropism happens in shoots - is a response to light - auxins produced in shoot tip - auxins moves to shaded side of shoot tip - cell elongation on shaded side - shoot bends towards the light - this is positive phototropism - more efficient photosynthesis |
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Explain how growth hormones cause phototropism and gravitropism in plants (6 marks - second half - gravitropism) |
- gravitropism / geotropism happens in roots - is a response to gravity - auxins produced in root tip - auxins moves to lower side of root tip - cell elongation stops on lower side - root bends downwards - this is positive gravitropism - more access to water / anchorage improved |
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Energy is lost between each trophic level of a food chain. Suggest how this energy is lost between each trophic level. |
- excretion - not all of organism eaten /some of organism isindigestible - respiration - movement - temperature regulation |
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Explain how the recycling of paper and plastics can benefit the environment (6 marks - first half - paper). |
- paper can be recycled which will reduce the needfor cutting down trees - more trees will be left growing removing carbondioxide - habitats for animals not destroyed - less space needed for landfill - less pollution relating to burning of waste /machinery cutting down of trees |
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Explain how the recycling of paper and plastics can benefit the environment (6 marks - second half - plastic). |
- plastic can be recycled which will reduce the demand for fossil fuels
- more fossil fuels available for other uses - less space needed for landfill - less pollution relating to burning of waste - plastic is slow to decompose - less energy used in recycling compared to making new products - the more products that are recycled the less pollution in the atmosphere and in the water supply |
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Explain why alcohol causes a change in reaction time. |
- alcohol is a depressant - slows down the activity of thebrain / reaction time increases - slows down neurotransmission - slows down transmission at thesynapse |
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Darwin’s finches are an example of speciation due to geographical isolation. Suggest how these species of finches could have evolved |
- variation between species/beak sizes/ shapes - due to mutation - competition for resources - survival of the fittest/those best adapted to theenvironment survived - those who survive passtheir genes/characteristicsonto their offspring - natural selection |
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Converting ammonia in th soil to nitates in the soil is known as... |
nitrification |
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Explain how plants use the nitrates from the soil. |
- used to make protein - for growth |
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Describe how the over-use of nitrate fertilisers can cause eutrophication. |
- nitrates leak into water - causes algae and small plants growrapidly - underwater plants cannotphotosynthesise because of the lack of sunlight - causes plants to die - decomposers / decomposing bacteria break down the dead plants - these bacteria use up oxygenduring respiration - causes oragnisms like fish in water to die |
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Explain the relationship between legume plants and the bacteria growing in their root nodules. |
- bacteria use nitrogen / nitrogenfixing bacteria - make ammonia / ammonium /nitrogen compounds /nitrates foruse by plants - bacteria protected within theroot nodule - bacteria obtain chemicalsubstances / glucose / sugarfrom the plant in return - this is called a mutualism |
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Suggest how a change in body mass may cause a person to develop type 2diabetes. |
- increasing body massleads to over weight /obesity
- don’t respond to insulin /reference to insulinresistance |
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Describe how the human body acts in response to low glucose levels in the blood. |
- glucagon is released - from the pancreas - glycogen to glucose - in the liver / musclecells - which acts to raise bloodglucose levels as more gluscose is released into blood NOTE: Mark scheme states only corrrect spellings for glucagon/glycogen accepted |
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Fruit ripening is one use of plant hormones. Describe the other uses of plant hormones in crop production. (6 marks - first half - selctive weedkillers and seedless fruit production) |
selective weedkillers - allows broad-leaved plants to grow uncontrollably and die - narrower-leaved plants and crops left unaffected - auxins and or gibberellins are used seedless fruit production - the fruit will develop but the seeds inside will not - fruits are able to grow larger (larger biomass) - gibberellins are used |
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Fruit ripening is one use of plant hormones. Describe the other uses of plant hormones in crop production. (6 marks - second half - rooting powders) |
rooting powders - plant cuttings are dipped into rooting powder - roots develop rapidly - large number of plants can be produced from the sameplant - no need to wait for plants to grow from seeds - auxins are used |
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The temperature of hydrothermal vents can be very high. Pompeii worms live in hydrothermal vents. Suggest a feature that helps to protect the Pompeii worm from the extremeheat. |
- large surface area tofacilitate heat loss - insulating/fat layer - - correct adaptation of skin /fur / hair - ref to not needing to regulatetemperature as poikilothermic |
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Explain, using Darwin’s theory of evolution, how variation can lead to aspecies evolving. |
- competition occursbetween members of aspecies - best suited / betteradapted members survive - these members willreproduce more times - the members who copeless well will die /extinction occurs - genes would be passed on to offsring - reference to naturalselection |
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Describe what is meant by the term speciation |
- the formation of a newspecies / newcharacteristics - due to geographicalisolation - no longer able to breedwith the original species |
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Suggest how farming can lead to a build-up of nutrients in the lake |
- over use of nitrates /phosphates fertilisers - leacking into the lake - sewage leakage into thelake |
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Explain how soil bacteria produce nitrates. |
- decomposers /decomposerbacteria - bacteria /they break downdead animal and plantmatter in the soil - into ammonia/ nitrites - ammonia / nitrites are converted intonitrates - by nitrifying bacteria |
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Name one type of bacteria that reduce the nitrate content of soil. |
denitrifying bacteria |
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A person with a body temperature of 37.9 °C had a body temperature of37.5 °C one hour later.
Explain how thermoregulation causes this reduction in body temperature. |
- hypothalamus controlsbody temperature
- causing the body to sweat more - sweating cools the bodyby evaporation of water/ sweat - vasodilation - heat lost by radiation - this is called negativefeedback |
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Explain how exercise can cause body temperature to increase. |
- muscles contract andrelax - friction - releasing heat byrespiration |
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Define the term drug. |
- a chemical substance - has an effect on the body /nervous system / brain - causing psychological /physiological / behaviouralchanges |
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Describe a long-term effect of alcohol abuse. |
- addiction - liver / brain /kidneydamage - cirrhosis / cancer |
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Discuss the ethics of allowing alcoholics to have an organ transplant. |
- alcoholics have causedtheir liver to fail by theiraddiction - if alcoholics continue todrink, the organ could bedamaged - other people may deservethe liver transplant more vs - addiction is an illness - everybody has a right tolife |
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Explain why a person with cystic fibrosis (CF) may lose body mass |
- mucus blocks pancreatic duct /small intestine wall /digestive system - preventingenzymes being released into smallintestine - less digestion of food - less absorption of nutrients |
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Explain the inheritance of sickle cell disease in a family with a heterozygous fatherand a homozygous recessive mother (6 marks). |
- mother gametes = d, d - father gametes = D, d - offspring = 50% Dd, 50% dd - probability of offspring with sickle cell disease = 50% - probability of carrier / heterozygous = 50% - both parents will give one allele to the possible offspring - the father can give either the dominant or recessive allele - the mother can only give a recessive allele - a dominant and recessive allele will result in heterozygousoffspring |
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A person with diabetes cannot control... |
- the glucose content of theirblood |
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Explain how Type 1 diabetes can be controlled. |
- the hormone insulin - insulin is injected intosubcutaneous fat - use a low carbohydrate/healthy diet - increase exercise - to lower blood glucoselevels / when bloodglucose levels get too high/ regulate glucoselevels |
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Explain how impulses are transmitted in a reflex arc to prevent a person frominjuring themselves (6 mark). |
- a reflex response is an involuntary response - reflex responses do not involve the brain - reflex responses involve sensory neurones - reflex responses involve relay neurones - reflex responses involve motor neurones - relay neurones are in the spinal cord - impulses travel along neurones as electrical signals - the axon is insulated by the myelin sheath - which ensures the electrical signal does not lose energy - at the junction between two neurones there is a synapse - the message is carried across the synapse byneurotransmitters - the message travels from the stimulus along the axon anddendron of the sensory neurone to the spinal cord - the reflex arc is important to keep the body safe |
