AQA Biology Past Papers (PDF)

Version 1.1 Biology essay titles This document contains the essay titles and mark schemes used in AQA A-level Biology examinations since 2007. The specifications these exam questions came from are no longer in use, but the marking method has largely remained unchanged. Further guidance on the marki...

Version 1.1 Biology essay titles This document contains the essay titles and mark schemes used in AQA A-level Biology examinations since 2007. The specifications these exam questions came from are no longer in use, but the marking method has largely remained unchanged. Further guidance on the marking method used with the essay can be found in Paper 3 Essay marking guidance. Year Question Title BIOL5 The importance of responses to changes in the internal and external 2015R 10a environment of an organism. The importance to humans of the control of growth, reproduction and 2015R 10b development of organisms, including themselves. The importance of proteins in the control of processes and responses in 2015 10a organisms. 2015 10b The causes and importance of variation and diversity in organisms. Cells and organisms carry out exchanges with their external 2014 10 a environment to maintain their internal environment. 2014 10 b How energy is transferred within and between organisms. The membranes of different types of cells are involved in many different 2013 10 a functions. There are many different types of relationships and interactions 2013 10 b between organisms. 2012 10 a The importance of shapes fitting together in cells and organisms 2012 10 b How bacteria can affect the lives of humans and other organisms 2011 10 a Using DNA in science and technology A cycle is a biological pathway or process in which the end product of 2011 10 b one cycle becomes the starting point for the next. Write an essay about cycles in biology Carbon dioxide may affect organisms directly or indirectly. Describe and 2010 10 a explain these effects. AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. 2010 10 b The causes of disease in humans SPEC B 2010 A The movement of substances within living organisms 2010 B Cycles in Biology 2009 A Ions and organisms 2009 B DNA and the transfer of information. The part played by the movement of substances across cell 2008 A membranes in the functioning of different organs and organ systems The part played by enzymes in the functioning of different cells, tissues 2008 B and organs. 2007 A Movements inside cells 2007 B Transfers through ecosystems SPEC A 2010 A Carbon dioxide in organisms and ecosystems. Why the offspring produced by the same parents are different in 2010 B appearance 2009 A The uses of water in living organisms. 2009 B The transfer of energy within and between organisms 2008 A Hydrogen bonds and their importance in living organisms. How nitrogen-containing substances are made available to and are 2008 B used 2007 A Carbon dioxide in organisms and ecosystems. Why the offspring produced by the same parents are different in 2007 B appearance AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 2 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. BIOL5 Essay Instructions You should write your essay in continuous prose. Your essay will be marked for its scientific accuracy. It will also be marked for your selection of relevant material from different parts of the specification and for the quality of your written communication. The maximum number of marks that can be awarded is:  Scientific content 16  Breadth of knowledge 3  Relevance 3  Quality of written communication 3. AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 3 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. Mark Schemes: June 2015R 10 (a) The importance of responses to changes in the internal and external environment of an organism. Question Marking guidance Mark Comments T - 3.1.3 Transport in and out of cells (of The topics listed contain 10 (a) specific substances) 25 material that could be I - 3.1.6 Immune response made relevant to the title. Writing about these Hb - 3.2.4 Haemoglobin topics in a general sense Tr - 3.2.7 Transpiration – response to may not address the environmental factors – gas exchange in question. plants Candidates may make B - 3.2.9 Behaviour correct use of material A - 3.2.10 Adaptation and selection from other topics. P - 3.4.8 Changes in populations – selection A* includes where pressures candidates use R - 3.5.1 Responses to stimuli – plants and information about a topic tropisms – control of heart rate in the specification but go Tk - 3.5.1 Taxes and kineses beyond what is expected for our A-level. Rc - 3.5.1 Receptors H - 3.5.2 Control of Heart Rate Sn - 3.5.1 and 2 Simple reflexes and neurones and synapses Hr - 3.5.2 and 5.4 Hormones and responses C - 3.5.2 Chemical mediators Ho - 3.5.4 Homeostasis – response to changes in internal environment F - 3.5.5 Feedback G - 3.5.7 Gene AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 4 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. June 2015R 10 (b) The importance to humans of the control of growth, reproduction and development of organisms, including themselves. Question Marking guidance Mark Comments A - 3.1.1 Pathogens (and invasion of human 10 (b) 25 The topics listed contain tissues) and 3.2.10 Antibiotic resistance – material that could be control of bacterial growth made relevant to the title. Ch - 3.1.3 Cholera Writing about these topics in a general sense I - 3.1.6 Immune response and vaccination may not address the (to control growth of pathogens) question. B - 3.2.11 Human influence on biodiversity Candidates may make Hp - 3.4.1 Human populations correct use of material Hf - 3.4.5 Humans and farming practices – from other topics. and 3.2.3 selective breeding A* includes where F - 3.4.6 Use of fertilisers and pesticides candidates use S - 3.4.7 Succession – control of information about a topic in the specification but go G - 3.4.8 Genetics – prediction of inherited beyond what is expected conditions for our A-level. Ge - 3.5.7 Control of gene expression – stem cells C - 3.5.7 Regulation of gene expression – prevention, treatment and cure of cancer – and 3.2.5 Mitosis and cancer Gc - 3.5.8 Gene cloning and transfer Gt - 3.5.8 Gene therapy AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 5 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. June 2015 10 (a) The importance of proteins in the control of processes and responses in organisms. Question Marking guidance Mark Comments Cat. Enzymes as catalysts 10 (a) 25 The topics listed contain Met. Enyzmes control metabolic pathways material that could be made relevant to the title. R. Proteins/enzymes in respiration Writing about these P. Proteins/enzymes in photosynthesis topics in a general sense may not address the Mb. Control of movement across question. Membranes Candidates may make IM. Immunology correct use of material Hb. Haemoglobin from other topics. DNA. DNA A* includes where Pc. Pacinian corpuscles – stretch mediated candidates use sodium channels information about a topic in the specification but go AP. Action potentials beyond what is expected S. Synaptic transmission for our A-level. Hm. Protein/peptide hormones T. Enzymes in gene transcription and Translation TF. Transcription factors and receptors GT. Gene therapy involving proteins AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 6 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. June 2015 10 (b) The causes and importance of variation and diversity in organisms. (25 marks) Question Marking guidance Mark Comments A. Antigenic variation in pathogens – 10 (b) 25 The topics listed contain antigenic variation in e.g. viruses material that could be made relevant to the title. E. Evolution of antibiotic-resistance in Writing about these Bacteria topics in a general sense may not address the DNA. Genetic diversity because of question. differences in DNA – comparing base Candidates may make sequences correct use of material G. Genes, alleles and proteins produced from other topics. P. Comparing protein sequences A* includes where AS. Selection – selective breeding, candidates use artificial selection information about a topic in the specification but go FG. Founder effect/genetic bottlenecks beyond what is expected Sp. Species diversity and index of for our A-level. Diversity C. Causes of variation in populations – Meiosis DV. Advantages of variation – disease, food chains, adaptation S. Succession GP. Gene pools and evolution, natural Selection Sp. Speciation, geographical isolation GMT. Gene mutation GE. Differences in gene expression GMT. Genetically modified organisms GF. Genetic fingerprinting AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 7 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. June 2014 Biol 5 10 (a) Cells and organisms carry out exchanges with their external environment to maintain their internal environment. (25 marks) Question Marking guidance Mark Comments H - Homeostasis (concept of) 10(a) The topics listed contain D - Digestion and absorption material that could be made relevant to the title. C - Cells Writing about these topics L - Lung function in a general sense may not G - Gas exchange address the question. W - Passage of water through plant Candidates may make Nc - Nutrient cycles correct use of material from other topics. R - Response to stimuli N- Neurones A* includes where candidates use information T - Temperature control about a topic in the Tf - tissue fluid and its formation specification but go beyond what is expected B - Control of blood glucose concentration for our A-level. Nf - Negative feedback Gn - Gene expression AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 8 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. June 2014 Biol 5 10 (b) How energy is transferred within and between organisms Question Marking guidance Mark Comments P - Photosynthesis 10(b) The topics listed contain Ec - Energy transfer through ecosystems material that could be F - Food production made relevant to the title. Writing about these topics D - Digestion (as in fuel) in a general sense may Ab - Absorption (by cells) not address the question. Mt - Mass transport Candidates may make R - Respiration correct use of material from other topics. A - ATP Sr - Stimuli and responses A* includes where candidates use Mc - Muscle contraction information about a topic N - Nerve impulses in the specification but go beyond what is expected for our A-level. AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 9 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. BIOL5 2013 10(a) The membranes of different types of cells are involved in many different functions (25 marks) Question Marking guidance Mark Comments 10(a) 1. Membrane function as selectively 25 The emphasis in permeable barrier answers should be on the involvement of 1. Transport mechanisms across membranes in membranes processes, not just the processes themselves 1. Absorption and co-transport of sodium ions and glucose Breadth, one mark for use of an example from 2. Photosynthesis, chloroplast, thylakoids each of the following approaches: 2. Respiration, mitochondrion and cristae 1. Membranes – basic 2. Protein secretion, RER, SER and Golgi functions 3. Surface receptors/antigen and immune response 2. Organelle membranes 3. Cell division 3. Cell surface membranes 3. Vertical and horizontal transmission – membranes and bacteria 4. Processes – eg protein secretion, synaptic 3. Pacinian corpuscle transmission, cell division 4. Tropisms – movement of IAA 4. Nerve impulses/action potentials 4. Synaptic transmission 4. Muscle contraction, calcium ion movement/storage 4. Hormones - eg Blood glucose regulation – insulin and glucagon 4. Osmosis, including water movement in plants AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 10 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. BIOL 5 2013 10 (b) There are many different types of relationships and interactions between organisms (25 marks) Question Marking guidance Mark Comments 10(b) 1. Pathogens and effects on host 25 The emphasis in answers should be on 1. Cholera the relationships and interactions between 1. TB organisms not just the topics themselves 2. Taxonomy Breadth, one mark for use 2. Classification and evolution of an example from each of the following 2. Inheritance and evolution approaches – 3 max: 2. Genetic code, universal 2. Behaviour 1. Pathogen and host 2. Populations and evolution, variation 2. Evolution (related topics) between individuals within a species 3. Ecological 3. Relationships within ecosystems – eg predator/prey 4. Human intervention in relationships 3. Energy transfer in ecosystems 3. Nutrient cycles, the organisms involved 3. Succession, biodiversity, species and individuals in a community 4. Human impacts on the environment and its effect on relationships between organisms – including farming 4. Gene technology and GMO and selective breeding 4. Antibiotic resistance AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 11 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. BIOL5 June 2012 10 (a) The importance of shapes fitting together in cells and organisms Question Marking guidance Mark Comments 10 (a) Proteins and Enzymes 25 3.1.2 Enzyme properties and digestion 3.1.2 Protein structure 3.1.3 Plasma membrane structure and cell transport 3.1.6 Antigens, antibodies, B cells & T cells 3.1.6 Vaccines Nucleic Acids 3.2.2 Structure of DNA 3.2.5 DNA Replication (not PCR) 3.5.7 Transcription & translation 3.5.8 Transcriptional factors, oestrogen, siRNA 3.5.8 Restriction enzymes Physiology 3.2.4 Haemoglobin 3.5.2 Action potentials & synaptic transmission 3.5.3 Muscle contraction 3.5.4 Control of blood glucose concentration 3.5.5 Control of mammalian oestrous cycle AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 12 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. BIOL5 June 2012 10 (b) How bacteria can affect the lives of humans and other organisms Question Marking guidance Mark Comments 10 (b) Bacteria and Disease 25 3.1.1 Pathogens 3.1.2 Lactose intolerance 3.1.3 Cholera 3.1.4 Tuberculosis 3.2.10 Resistance to antibiotics Ecological Importance 3.4.6 Carbon cycle 3.4.6 Nitrogen cycle 3.4.6 Eutrophication Making Use of Bacteria 3.5.8 Use of bacterial enzymes e.g. restriction endonuclease, DNA polymerase for PCR 3.5.8 Use of bacterial plasmids e.g. in vivo gene cloning, genetically- modified crops, gene therapy 3.5.8 Use of bacteria to produce useful chemicals AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 13 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. June 2011 Biol5 10 (a) Using DNA in science and technology Question Marking guidance Mark Comments 10 (a) DNA and classification 25 Structure of DNA Differences in DNA lead to genetic diversity Comparison of DNA base sequences DNA hybridisation Genetic engineering and making useful substances Plasmids The use of recombinant DNA to produce transformed organisms that benefit humans Other uses of DNA Cell cycle and treatment of cancer Gene therapy; Medical diagnosis and the treatment of human disease; The use of DNA probes to screen patients for clinically important genes. AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 14 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. June 2011 Biol5 10 (b) A cycle is a biological pathway or process in which the end product of one cycle becomes the starting point for the next. Write an essay about cycles in biology Question Marking guidance Mark Comments 10 (b) Ecological cycles 25 Nutrient cycles Carbon cycle Nitrogen cycle Biochemical cycles Enzyme action Synthesis of ATP from ADP Light-independent reaction The Krebs cycle Physiological and genetic cycles The mechanism of breathing The cardiac cycle The cell cycle Muscle contraction Oestrous cycle AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 15 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. 2010 June Biol5 10 (a) Carbon dioxide may affect organisms directly or indirectly. Describe and explain these effects. Question Marking guidance Mark Comments 10 (a) Carbon dioxide affects the physiology of 25 organisms Pulmonary ventilation and the mechanism of breathing Light-independent reaction of photosynthesis. Limiting factors Role of chemoreceptors in controlling heart rate The direct effects of increasing carbon dioxide concentration Respiration, photosynthesis and human activity giving rise to short-term fluctuations and long-term change. Yield of crop plants Carbon cycle Indirect effects of increasing carbon dioxide concentration Role of carbon dioxide in producing global warming; Life cycles and number of insect pests; Distribution of animals and plants; Effect of temperature on enzymes; AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 16 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. 2010 June Biol5 10 (b) The causes of disease in humans Question Marking guidance Mark Comments 10 (b) Pathogens 25 Pathogens include bacteria, viruses and fungi Pathogens cause disease by damaging cells and producing toxins Cholera bacteria produce toxins resulting in diarrhoea Symptoms and transmission of pulmonary tuberculosis Horizontal gene transmission and MRSA Lifestyle Risk factors associated with cancer and coronary heart disease The effects of fibrosis, asthma and emphysema on lung function The biological basis of heart disease Genetics Differences in bases may lead to non- functional enzymes Relationship between the cell cycle and cancer Proto-oncogenes and tumour suppressor genes Gene mutations AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 17 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. SPEC B Jan 2010 Unit 6/7/8 Essay A: The movement of substances within living organisms Question Marking guidance Mark Comments 1. Osmosis 25 2. Across cell membranes 3. Movement of water/mineral ions in plants 4. Enzymes, kinetic energy and reactions 5. Gut and absorption 6. DNA Transcription and translation 7. Mitosis and Meiosis 8. Sperm and fertilisation 9. Blood vessels and heart 10. Exchange in capillaries 11. Electron transport 12. Nerve impulses/action potential 13. Synapses 14. Muscle contraction 15. Alveolar gas exchange 16. Translocation 17. Photosynthesis 18. Kidneys Essay B: Cycles in Biology Question Marking guidance Mark Comments 1. Large and small biological molecules, Essay B condensation and hydrolysis 25 2. Enzymes 3. Cell cycle – Mitosis and meiosis 4. PCR 5. Mammalian blood circulation 6. Calvin cycle 7. Krebs cycle 8. ATP and ADP 9. Negative feedback 10. Nitrogen cycle 11. Carbon cycle 12. Menstrual cycle 13. Muscle contraction 14. Nerve impulses 15. Predator prey 16. Electron transport chain AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 18 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. SPEC B June 2009 Unit 6/7/8 Essay A: Ions and organisms Question Marking guidance Mark Comments 1. Osmosis and turgor Essay A 25 2. Haemoglobin dissociation, pH and carbon dioxide 3. Uptake/movement of water/mineral ions by/in plants 4. Ions in biological molecules 5. Hydrogen, photosynthesis and respiration 6. Anaerobic respiration and lactate 7. Nerve impulses and synaptic transmission 8. Regulation of blood water potential/kidney function 9. Muscle contraction 10. Nitrogen cycle 11. Eutrophication 12. Movement across membranes 13. Cystic fibrosis Essay B: DNA and the transfer of information Question Marking guidance Mark Comments 1. Genes/how information is carried on Essay B 25 Any other sensible 2. DNA example of the transfer of 3. Replication of DNA information involving DNA 4. Cell division - Mitosis and meiosis should be credited. 5. Transcription and translation 6. Mutation 7. Genetic engineering 8. Gene therapy 9. Genetically modified organisms 10. Variation (in populations) 11. Evolution 12. Inheritance AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 19 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. SPEC B June 2008 Unit 6/7/8 (25 marks) Essay A: The part played by the movement of substances across cell membranes in the functioning of different organs and organ systems Question Marking guidance Mark Comments 1. Plasma membranes and movement Essay A 25 Any other sensible across example of the movement 2. Gaseous exchange system/ lungs 3. Digestive system/small intestine of substances across cell membranes in the 4. Blood vascular system functioning of different 5. Transpiration/root/stem organs and organ systems 6. Mass flow/leaf/stem 7. Nervous system/eye should be credited 8. Excretory system/ kidney 9. Muscle systems 10. Liver, blood glucose 11. Root mineral ions 12. Lungs cystic fibrosis Essay B: The part played by enzymes in the functioning of different cells, tissues and organs Question Marking guidance Mark Comments 1. Action of enzymes Essay B 25 Any other sensible 2. Enzyme properties example of the part played 3. Extracellular digestion by enzymes in the 4. Nutrient cycles functioning 5. Digestion in humans 6. Replication of DNA of different cells, tissues and organs should be 7. Protein and enzyme synthesis credited. 8. Metabolic pathways 9. Mutations 10. Coenzymes and enzyme action 11. Homeostasis 12. Neurone/synapse 13. Muscle contraction 14. Pesticide toxicity AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 20 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. SPEC B 2007 June series Unit 6/7/8 ESSAY A: Movements inside cells Question Marking guidance Mark Comments 1. Plasma membranes and movement Essay A 25 across 2. Protein synthesis 3. Movement through ER and Golgi 4. Cell division and chromosome movement 5. Water movement in plants/xylem 6. Translocation 7. Neurones and synaptic vesicles 8. Actin and myosin 9. DNA replication and mutation 10. Electron transport chains 11. Molecular/atomic/ionic movement Essay B: Transfers through ecosystems Question Marking guidance Mark Comments 1. Photosynthesis – energy transfer Essay B 25 2. Respiration – energy transfer 3. Carbon cycle 4. Nitrogen cycle 5. Food chains 6. Ecological pyramids 7. Pesticide toxicity/bioaccumulation 8. Eutrophication 9. Digestion and absorption 10. Transfer of genetic material 11. Water cycle AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 21 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. SPEC A Jan 2010 Unit 8 Essay A: Carbon dioxide in organisms and ecosystems Question Marking guidance Mark Comments Biochemistry Essay A 25 14.6 The biochemistry of photosynthesis 14.8 The biochemistry of respiration 11.6 C4 photosynthesis in maize Physiology 15.4 Gas exchange surfaces 10.8 Changes is cardiac output and pulmonary ventilation with exercise 15.5 The transport of respiratory gases Ecology 11.6 The effect of carbon dioxide on productivity 14.9 Decomposition and recycling maintain the balance of nutrients in an ecosystem The greenhouse effect is not specifically mentioned but should be credited here if discussed. AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 22 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. Essay B: Why the offspring produced by the same parents are different in appearance Question Marking guidance Mark Comments Genes Essay B 25 11.3 Genes incorporate coded information which influence phenotype 14.2 Gene mutation Environment 14.2 Environment variation 15.7 Dietary requirements of insects Chromosomes and cells 11.2 and 14.1 Meiosis 14.1 Principles of Mendelian inheritance 14.2 Polygenetic inheritance 16.1 Gametes and gamete formation. Fertilisation AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 23 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. SPEC A Biology and Human Biology June 2009 Paper 8/9 Essay A: The uses of water in living organisms Question Marking guidance Mark Comments Water in chemical reactions Essay A 25 10.4 Condensation and hydrolysis 14.6 Photolysis 16.4 Digestion and absorption Water and physiology 10.7 Circulation Tissue fluid and its circulation 16.11 Temperature control 16.2 The fetus in its uterine environment Water and Osmosis 10.3 Water potential and osmosis 10.2 Cell walls and support in plants 16.11 Urine formation (Biology only) AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 24 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. Essay B: The transfer of energy within and between organisms Question Marking guidance Mark Comments Autotrophic nutrition Essay B 25 14.6 Photosynthesis 11.6 Factors that limit the rate of photosynthesis Energy transfer 14.9 Carbon cycle 14.10 The influence of deforestation of carbon cycling 14.7 Ecological pyramids and the transfer of energy 16.4 Digestion and absorption Energy loss 14.8 Respiration and ATP 10.3 Active transport 15.9 Receptors convert stimuli into nerve impulses AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 25 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. SPEC A Biology and Human Biology June 2008 Paper 8/9 Essay A: Hydrogen bonds and their importance in living organisms Question Marking guidance Mark Comments Hydrogen bonds associated with the Essay A properties of water 25 15.1 The passage of water through a plant and cohesion tension Hydrogen bonds associated with secondary and tertiary structure 10.4 The structure of proteins, starch and cellulose 10.5 Enzymes Hydrogen bonds associated with nucleic acids 11.3 DNA as genetic material, structure of nucleic acids 11.4 Gene technology Essay B: How nitrogen-containing substances are made available to and are used Question Marking guidance Mark Comments Nutrient cycling Essay B 25 Nitrogen cycle The influence of deforestation of nitrogen cycling The uses of proteins Proteins as biological molecules Enzymes and enzyme action Haemoglobin and the exchange of respiratory gases The use of membrane proteins in the nervous system The uses of nucleic acids and other nitrogen-containing substances DNA and protein synthesis Chlorophyll, NADP and photosynthesis ATP and respiration AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 26 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. SPEC A Biology and Human Biology June 2007 Paper 8/9 Write an essay on one of the following topics. You should select and use information from different parts of the specification. Credit will be given not only for the biological content, but also for the selection and use of relevant information and for the organisation and presentation of the essay. Essay A: Carbon dioxide in organisms and ecosystems Question Marking guidance Mark Comments Biochemistry Essay A 25 The biochemistry of photosynthesis 14.6 The biochemistry of respiration 14.8 C4 photosynthesis in maize 11.6 Physiology Gas exchange surfaces 15.4 Changes in cardiac output and pulmonary ventilation with exercise 10.8 The transport of respiratory gases 15.5 Ecology The effect of carbon dioxide on productivity; 11.6 Decomposition and recycling maintain the balance of nutrients in an ecosystem 14.9 The greenhouse effect is not specifically mentioned but should be credited here if discussed AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 27 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX. Essay B: Why the offspring produced by the same parents are different in appearance Question Marking guidance Mark Comments Genes Essay B 25 Genes incorporate coded information which influences phenotype 11.3 Gene mutation 14.2 Environment Environment variation 14.2 Dietary requirements of insects 15.7 Chromosomes and cells Meiosis 11.2 and 14.1 Principles of Mendelian inheritance 14.1 Polygenetic inheritance 14.2 Gametes and gamete formation. Fertilisation 16.1 AQA Education (AQA) is a re gistered charity (number 1073334) and a company limite d by g uarantee re gistered in 28 of 28 Eng land and Wales (number 3644723). Our registered address is AQA, De vas S treet, Manchester M15 6EX.