A2 SYLLABUS
UNIT 4
Topic 5 - On the wild side
Students will be assessed on their ability to:
1. demonstrate knowledge and understanding of the how science works areas LISTED IN THE TABLE ON PAGE 13 OF THIS SPECIFICATION.
2. Describe the structure of chloroplasts in relation to their role in photosynthesis.
3. Describe the overall reaction of photosynthesis as requiring energy from light to split apart the strong bonds in water molecules, storing the hydrogen in a fuel (glucose) by combining it with carbon dioxide and releasing oxygen into the atmosphere.
4. Describe the light-dependent reactions of photosynthesis including how light energy is trapped by exciting electrons in chlorophyll and the role of these electrons in generating ATP, and reducing NADP in photophosphorylation and producing oxygen through photolysis of water.
5. Describe how phosphorylation of ADP requires energy and how hydrolysis of ATP provides an immediate supply of energy for biological processes.
6. Describe the light-independent reactions as reduction of carbon dioxide using the products of the light-dependent reactions (carbon fixation in the Calvin cycle, the role of GP, GALP, RuBP and RUBISCO) and describe the products as simple sugars that are used by plants, animals and other organisms in respiration and the synthesis of new biological molecules (including polysaccharides, amino acids, lipids and nucleic acids).
7. Carry out calculations of net primary productivity and explain the relationship between gross primary productivity, net primary productivity and plant respiration.
8. Calculate the efficiency of energy transfers between trophic levels.
9. Discuss how understanding the carbon cycle can lead to methods to reduce atmospheric levels of carbon dioxide (including the use of biofuels and reforestation).
10. Explain that the numbers and distribution of organisms in a habitat are controlled by biotic and abiotic factors.
11. Describe how to carry out a study on the ecology of a habitat to produce valid and reliable data (including the use of quadrats and transects to assess abundance and distribution of organisms and the measurement of abiotic factors, eg solar energy input, climate, topography, oxygen availability and edaphic factors).
12. Explain how the concept of niche accounts for distribution and abundance of organisms in a habitat.
13. Describe the concept of succession to a climax community.
14. Outline the causes of global warming – including the role of greenhouse gases (carbon dioxide and methane, CH4) in the greenhouse effect.
15. Describe the effects of global warming (rising temperature, changing rainfall patterns and seasonal cycles) on plants and animals (distribution of species, development and life cycles).
16. Explain the effect of increasing temperature on the rate of enzyme activity in plants, animals and micro-organisms.
17. Describe how to investigate the effects of temperature on the development of organisms (eg seedling growth rate, brine shrimp hatch rates).
18. Analyse and interpret different types of evidence for global warming and its causes (including records of carbon dioxide levels, temperature records, pollen in peat bogs and dendrochronology) recognising correlations and causal relationships.
19. Describe that data can be extrapolated to make predictions, that these are used in models of future global warming, and that these models have limitations.
20. Discuss the way in which scientific conclusions about controversial issues, such as what actions should be taken to reduce global warming or the degree to which humans are affecting global warming, can sometimes depend on who is reaching the conclusions.
21. Describe how evolution (a change in the allele frequency) can come about through gene mutation and natural selection.
22. Explain how reproductive isolation can lead to speciation.
23. Describe the role of the scientific community in validating new evidence (including molecular biology, eg DNA, proteomics) supporting the accepted scientific theory of evolution (scientific journals, the peer review process, scientific conferences).
Topic 6 - Infection, immunity and forensics
Students will be assessed on their ability to:
1. Demonstrate knowledge and understanding of the How Science Works areas listed in the table on page 13 of this specification.
2. Explain the nature of the genetic code (triplet code, non-overlapping and degenerate).
3. Explain the process of protein synthesis (transcription, translation messenger RNA, transfer RNA, ribosomes and the role of start and stop codons) and explain the roles of the template (antisense) DNA strand in transcription, codons on messenger RNA, anticodons on transfer RNA.
4. Explain how one gene can give rise to more than one protein through post-transcriptional changes to messenger RNA.
5. Describe how DNA profiling is used for identification and determining genetic relationships between organisms (plants and animals).
6. Describe how DNA can be amplified using the polymerase chain reaction (PCR).
7. Describe how gel electrophoresis can be used to separate DNA fragments of different length.
8. Distinguish between the structure of bacteria and viruses.
9. Describe the role of micro-organisms in the decomposition of organic matter and the recycling of carbon.
10. Describe the major routes pathogens may take when entering the body and explain the role of barriers in protecting the body from infection, including the roles of skin, stomach acid, gut and skin flora.
11. Explain how bacterial and viral infectious diseases have a sequence of symptoms that may result in death, including the diseases caused by Mycobacterium tuberculosis (TB) and Human Immunodeficiency Virus (HIV).
12. Describe the non-specific responses of the body to infection, including inflammation, lysozyme action, interferon and phagocytosis.
13. Explain the roles of antigens and antibodies in the body’s immune response including the involvement of plasma cells, macrophages and antigen-presenting cells.
14. Distinguish between the roles of B cells (including B memory and B effector cells) and T cells (T helper, T killer and T memory cells) in the body’s immune response.
15. Explain how individuals may develop immunity (natural, artificial, active, passive).
16. Discuss how the theory of an ‘evolutionary race’ between pathogens and their hosts is supported by the evasion mechanisms as shown by Human Immunodeficiency Virus (HIV) and Mycobacterium tuberculosis (TB).
17. Distinguish between bacteriostatic and bactericidal antibiotics.
18. Describe how to investigate the effect of different antibiotics on bacteria.
19. Describe how an understanding of the contributory causes of hospital acquired infections have led to codes of practice relating to antibiotic prescription and hospital practice relating to infection prevention and control.
20. Describe how to determine the time of death of a mammal by examining the extent of decomposition, stage of succession, forensic entomology, body temperature and degree of muscle contraction.
Unit 5
Topic 7 - Run for your life
Students will be assessed on their ability to:
1. Demonstrate knowledge and understanding of the How Science Works areas listed in the table on page 13 of this specification.
2. Describe the structure of a muscle fibre and explain the structural and physiological differences between fast and slow twitch muscle fibres.
3. Explain the contraction of skeletal muscle in terms of the sliding filament theory, including the role of actin, myosin, troponin, tropomyosin, calcium ions (Ca2+), ATP and ATPase.
4. Recall the way in which muscles, tendons, the skeleton and ligaments interact to enable movement, including antagonistic muscle pairs, extensors and flexors.
5. Describe the overall reaction of aerobic respiration as splitting of the respiratory substrate (eg glucose) to release carbon dioxide as a waste product and reuniting of hydrogen with atmospheric oxygen with the release of a large amount of energy.
6. Describe how to investigate rate of respiration practically.
7. Recall how phosphorylation of ADP requires energy and how hydrolysis of ATP provides an accessible supply of energy for biological processes.
8. Describe the roles of glycolysis in aerobic and anaerobic respiration, including the phosphorylation of hexoses, the production of ATP, reduced coenzyme and pyruvate acid (details of intermediate stages and compounds are not required).
9. Describe the role of the Krebs cycle in the complete oxidation of glucose and formation of carbon dioxide (CO2), ATP, reduced NAD and reduced FAD (names of other compounds are not required) and that respiration is a many-stepped process with each step controlled and catalysed by a specific intracellular enzyme.
10. Describe the synthesis of ATP by oxidative phosphorylation associated with the electron transport chain in mitochondria, including the role of chemiosmosis and ATPase.
11. Explain the fate of lactate after a period of anaerobic respiration in animals.
12. Understand that cardiac muscle is myogenic and describe the normal electrical activity of the heart, including the roles of the sinoatrial node (SAN), the atrioventricular node (AVN) and the bundle of His, and how the use of electrocardiograms (ECGs) can aid the diagnosis of cardiovascular disease (CVD) and other heart conditions.
13. Explain how variations in ventilation and cardiac output enable rapid delivery of oxygen to tissues and the removal of carbon dioxide from them, including how the heart rate and ventilation rate are controlled and the roles of the cardiovascular control centre and the ventilation centre.
14. Describe how to investigate the effects of exercise on tidal volume and breathing rate using data from spirometer traces.
15. Explain the principle of negative feedback in maintaining systems within narrow limits.
16. Discuss the concept of homeostasis and its importance in maintaining the body in a state of dynamic equilibrium during exercise, including the role of the hypothalamus and the mechanisms of thermoregulation.
17. Explain how genes can be switched on and off by DNA transcription factors including hormones.
18. Analyse and interpret data on possible disadvantages of exercising too much (wear and tear on joints, suppression of the immune system) and exercising too little (increased risk of obesity, coronary heart disease (CHD) and diabetes) recognising correlation and causal relationships.
19. Explain how medical technology, including the use of keyhole surgery and prostheses, is enabling those with injuries and disabilities to participate in sports, eg cruciate ligaments repair using keyhole surgery and knee joint replacement using prosthetics.
20 Outline two ethical positions relating to whether the use of performance-enhancing substances by athletes is acceptable.
Topic 8 - Grey matter
Students will be assessed on their ability to:
1. Demonstrate knowledge and understanding of the How Science Works areas listed in the table on page 13 of this specification.
2. Describe how plants detect light using photoreceptors and how they respond to environmental cues.
3. Describe the structure and function of sensory, relay and motor neurones including the role of Schwann cells and myelination.
4. Describe how a nerve impulse (action potential) is conducted along an axon including changes in membrane permeability to sodium and potassium ions and the role of the nodes of Ranvier.
5. Describe the structure and function of synapses, including the role of neurotransmitters, such as acetylcholine.
6. Describe how the nervous systems of organisms can detect stimuli with reference to rods in the retina of mammals, the roles of rhodopsin, opsin, retinal, sodium ions, cation channels and hyperpolarisation of rod cells in forming action potentials in the optic neurones.
7. Explain how the nervous systems of organisms can cause effectors to respond as exemplified by pupil dilation and contraction.
8. Compare mechanisms of coordination in plants and animals, ie nervous and hormonal, including the role of IAA in phototropism (details of individual mammalian hormones are not required).
9. Locate and state the functions of the regions of the human brain’s cerebral hemispheres (ability to see, think, learn and feel emotions), hypothalamus (thermoregulate), cerebellum (coordinate movement) and medulla oblongata (control the heartbeat).
10. Describe the use of magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI) and computed tomography (CT) scans in medical diagnosis and investigating brain structure and function.
11. Discuss whether there exists a critical ‘window’ within which humans must be exposed to particular stimuli if they are to develop their visual capacities to the full.
12. Describe the role animal models have played in developing explanations of human brain development and function, including Hubel and Wiesel’s experiments with monkeys and kittens.
13. Consider the methods used to compare the contributions of nature and nurture to brain development, including evidence from the abilities of newborn babies, animal experiments, studies of individuals with damaged brain areas, twin studies and cross-cultural studies.
14. Describe how animals, including humans, can learn by habituation.
15. Describe how to investigate habituation to a stimulus.
16. Discuss the moral and ethical issues relating to the use of animals in medical research from two ethical standpoints.
17. Explain how imbalances in certain, naturally occurring, brain chemicals can contribute to ill health (eg dopamine in Parkinson’s disease and serotonin in depression) and to the development of new drugs.
18. Explain the effects of drugs on synaptic transmissions, including the use of L-Dopa in the treatment of Parkinson’s disease and the action of MDMA in ecstasy.
19. Discuss how the outcomes of the Human Genome Project are being used in the development of new drugs and the social, moral and ethical issues this raises.
20. Describe how drugs can be produced using genetically modified organisms (plants and animals and microorganisms).
21. Discuss the risks and benefits associated with the use of genetically modified organisms.
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