AQA BIOL4 Flash Cards

All common questions taken directly from past exam papers

How many genes does multiple allele inheritance involve?
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How does collecting data randomly aid an investigation?
1) It prevents bias results 2) It is representative of the whole population
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What are the advantages of using organic fertilisers?
1) Nutrients are released slowly 2) Greater range of nutrients present 3) Improves soil quality 4) Increases water holding capacity of the soil 5) Reduces leaching and hence eutrophication 6) Improves soil aeration 7) Already available-no cost
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What are the advantages of using inorganic fertilisers?
1) Known nutrient content 2) Fast acting 3) Nutrients distributed evenly 4) No pests present 5) Better to handle-easier to store 6) Nutrients are concentrated-small amount needed 7) Applied using light machinery-keeps soil aerated
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Why may fertilisers favour one crop over another?
1) It may contain a nutrient essential to growth in one species 2) Crops have different nutrient requirements 3) Fertilisers may contain an ingredient which inhibits growth
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Why is anaerobic respiration inefficient?
1) Oxygen is not the terminal electron acceptor 2) ETC cannot occur as a result 3) No Krebs cycle 4) However ATP is formed in glycolysis hence organisms can still survive
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What is reproductive isolation?
It is where organisms cannot interbreed with other groups due to having different gametes, courtship behavoir etc...
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How does ploughing dead plants into the soil act as an organic fertiliser?
1) Saprobiotic organism 2) Convert organic matter into ammonium ions 3) Ammonium ions converted to nitrite ions 4) Nitrite ions converted to nitrate ions 5) By nitrifying bacteria 6) Nitrate ions are absorbed to form amino acids/proteins
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How does the application of plants increase growth? (see Q8)
7) Application of plants produces increased growth 8) Decomposers respire and release CO2 9) CO2 is used by plants in photosynthesis
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What is the difference between decomposers and detritivores?
Decomposers secrete enzymes which break the food down outside of the body whereas detritivores ingest their food before breaking it down
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How do detritivores increase the activity of microbial decomposers when present?
1) They breakdown larger pieces of dead organic matter providing a larger surface area for the microbial activity 2) Add products of excretion 3) More nutrients present-higher C-N ratio
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What is a community?
It is a population of different species who live in the same habitat
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What is the main difference between a natural ecosystem and an agricultural ecosystem?
It has a larger species diversity due to increased habitats and more feeding opportuinties
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What must you compare when looking a distribution graphs?
1) The range of heights 2) Whether one has one extreme or not 3) Where the median is
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How do mutations occur and survive?
1) Mutations favour certain individuals 2) Survival of the fittest 3) Genetic modification
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What are the benefits of having short crop heights?
1) Less stem damage in winds 2) More energy used in seed formation as less growth occurs 3) Easier to harvest
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How does geographical isolation leads to new species forming? And hence they cannot reproduce
1) Population become separated by a physical barrier 2) No mixing of gene pools 3) Different selection pressures 4) Become adapted to local environment 5) Survive and reproduce 6) Mutation is not present in both groups 7) Change in allelic freq
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What is directional selection?
It is selection against one extreme, distribution/mode is shifted to the favoured extreme
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Where does sex-linked genes come from?
It comes from only one sex chromosomes either X or Y
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What is population?
It is the number of one species present in one habitat
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How does increased life expectancies occur?
Usually due to better health care facilities, better food etc...
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What evidence shows that an allele is dominant?
1) If recessive, both parents would be homozygous recessive 2) Hence all offspring will be recessive 3) However offspring offspring do not contain characteristic hence must be dominant
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How can you tell that the gene is not on the X chromosome?
1) The father always passes on one of the daughters X chromosome 2) If one of the daughter does not have the phenotypes of the father then it is not on the X chromosome
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Why is more ammonia produced?
1) Increase in the number of enzymes 2) More enzyme-substrate complexes 3) More bacteria produced 4) Hence more ammonia
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What measurements should be made to calculate the rate of respiration?
1) The distance moved by the air bubble/drop and the time taken 2) Mass of the specimen 3) Diameter of tubing
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Where is heat released in the mitochondria?
From the electron transport chain - redox reactions
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What information will farmers want to know prior to using a new treatment?
1) Will it affect the yield? 2) The costs of the treatment 3) How it is applied and frequency 4) Will it affect other organisms
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How does succession occur?
1) Colonisation by pioneer species 2) Change in environment caused by the species present 3) Enabese other species to colonise 4) Change in diversity 5) Stability increases 6) Climax community
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What are the advantages of using a biological agent to control pests?
1) Specific 2) Only needs one application-reproduces 3) Maintains low population of pest 4) Pests cannot develop resistance 5) Does not leave in chemical in the environment 6) Can be used in organic farming
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What are the disadvantages of using biological agents to control pests?
1) Does not get rid of pests completely 2) May become a pest itself 3) Slow acting-lag period
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How does speciation lead to a different species evolving?
1) Geographical isolation 2) Separate gene pools 3) Variation due to mutations 4) Different environmental conditions 5) Selection for different advantageous mutations 6) Survival of the fittest 7) Change in allelic freq 8) Long period of time
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What properties of ATP make it a suitable source of energy?
1) It is soluble 2) Energy is released in small amounts 3) Involves a single reaction
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Why is ATP synthesised in such large amounts?
1) ATP is unstable 2) ATP cannot be stored 3) Active transport needs ATP 4) ATP only releases a small amount of energy at a time
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What is the equation for net productivity?
Net productivity = Gross productivity - Respiratory loses
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How are extra nutrients used?
1) Stored as fat 2) Used for growth / movement
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How does the temperature affect mammals?
1) They will lose more energy 2) Use more energy to maintain their body temperature 3) By respiration / metabolismq
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What is the equation for birth rate?
Births per year / Total population (that year) x 1000
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Why do actual numbers of offspring can vary from predicted values?
1) The ratios are predicted 2) gametes may not be produced in equal numbers 3) Fertilisation of gametes is random 4) Only a small sample was taken
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How is reliability affected by counting?
1) Numbers and sizes may vary 2) Depending on the time of the day
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How does deforestation increase CO2 levels?
1) No vegetation left hence no photosynthesis 2) No CO2 removed by photosynthesis 3) Burning releases CO2 4) Hence CO2 levels increase
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How does CO2 get turned into organic substances in photosynthesis?
1) CO2 + RuBP --> 2 x G-3P 2) G-3P reduced to TP 3) Using ATP and NAHPH 4) TP gets regenerated into RuBP 5) Occurs in the light independant cycle
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How do you estimate a population size using the capture, mark and release method?
(Total number in first sample x Total number in second sample) / Number of marked in the second sample
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Explain how intensive rearing of domestic livestock increases net productivity?
1) Slaughtered when still growing-more energy transferred into biomass 2) Fed on concentrates feed-controlled diet 3) Movement restricted-less energy expelled 4) Kept inside-less energy lost as heat 5) Genetically selected for high productivity
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Describe and explain why the efficiency of energy transfer is different at different stages of the transfer?
1) Some light energy fails to strike the leaves 2) Efficiency of photosynthesis in plants is low 3) Respiratory loses 4) Lost as heat energy 5) Efficiency of transfer to consumers is greater than transfers to producers
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Describe and explain why the efficiency of energy transfer is different at different stages of the transfer?
6) Efficiency lower in older animals/herbivores/primary consumers 7) Carnivores use more of their food than herbivores
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Other cards in this set

Card 2


How does collecting data randomly aid an investigation?


1) It prevents bias results 2) It is representative of the whole population

Card 3


What are the advantages of using organic fertilisers?


Preview of the front of card 3

Card 4


What are the advantages of using inorganic fertilisers?


Preview of the front of card 4

Card 5


Why may fertilisers favour one crop over another?


Preview of the front of card 5
View more cards


Laura Dewhurst


great help! thanks

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