IGCSE生物复习tips.doc

Revision tipsNo one can teach you how to revise, as we all learn differently. All we can do is to suggest some guidelines and ideas for you to try. Some ideas will suit you, others may not. However, give all of them a chance and see if they work.Revision guidelines Start your revision early! You should start your revision at least three months before the IGCSE examination. Plan your revision. Split the work into chunks. We will give some advice on this later. Go through the chunks to ensure you understand each piece of work. If you do not understand something, ask for help. You can ask your teacher or a friend who is also studying the course, but do not delay and hope the problem will go away. It wont. You will never learn anything really well unless you understand it. Summarise the work in a form you can go through easily the next time. We will suggest ways of doing this later. Ensure that you have completed the summarising of the entire course at least a month before your exams start. Go through each summary at least twice more, referring back to more detailed notes where necessary. Make your revision active do not just sit and read the textbook or your notes. Find activities to make yourself think about what you are doing. The section on revision techniques in this room will give you some ideas on how to make your revision active. Remember that your exam papers will test your skills as well as your knowledge and understanding. Practising past questions will help you to make sure you know how to do calculations, handle data and so on. Look in the syllabus under the heading Assessment Objective B to make sure you know what these skills are. Dont forget to revise your practical work! Make sure you know which Paper you are entered for practical assessment (4, 5 or 6).Revision aimsWhen you revise, you are trying to:1. Improve your memoryYou are trying to increase the amount of biology that you can remember. Your brain quickly forgets. Most of what you try to learn by heart you will forget over the next two days. Nevertheless, you can help your brain to remember by using different revision techniques, such as the ones explained in the revision techniques section.2. Organise what you have studiedIf you organise what you have studied so that it all makes better sense, you will be able to remember more of it. You can organise it by linking together the main ideas. Remembering one idea will help you remember another. We will suggest ways of doing this later.3. Improve your understandingIf you can improve your understanding of the important underlying ideas in biology, you will be able to remember more of the details.Splitting the work into chunksIt is very much up to you how you do this. For example, you might like to split all of your biology up according to the arrangement of your notes or your file the chunks in which you were taught. Or you might like to use the syllabus and split this up into chunks. Or you might do it using groups of chapters in your textbook. Just doing this splitting exercise will help you to learn, because it makes you think about the subject as a whole.We hope that you will do your own splitting; however, here is one idea about how you might split the subjects using the textbook as a starting point. The subjects have been split up into six big chunks, and then one of these big chunks is broken down into smaller ones. Again, its really useful for you to do this for yourself, so dont just follow this example blindly without thinking about how you could make it work better for you.Six big chunks1Classification and cellsChapters 1, 2 and 32Nutrition and transportChapters 4, 5, 6, 7 and 83Respiration and excretionChapters 9 and 104Nerves and hormonesChapters 11, 12 and 135Reproduction and geneticsChapters 14 and 156EcologyChapters 16 and 17Chunk 1 split up1.1 Characteristics of living organismsReally quick and easy you can probably do this already.1.2 Naming living organismsMake sure you understand how the binomial system works and learn a couple of examples.1.3 Classifying organismsLearn the features that are characteristic of each of the groups listed in the syllabus. There is a lot of learning to do here, so allocate plenty of time for it. You could make yourself some flash cards with features on them one feature per card, such as has jointed legs, has eight jointed legs and so on then check that you can choose the correct set of cards for different kinds of organisms.1.4 Structure of plant and animal cellsMake sure you can draw labelled diagrams of them, and get all the names and spellings correct. Be able to compare them, and describe what each part does.1.5 Specialised cells: tissues, organs and systemsLearn the structure and function of each kind of cell listed in the syllabus. Make sure you can clearly relate each special structure to the particular function of that cell.1.6 MagnificationLearn the equation that links magnification and sizes of actual and illustrated specimens. Then practice using it lots of times. 1.7 Diffusion and osmosisLearn their definitions, but then make sure you understand them and why they are important to organisms if you dont, ask for help. Check that you can explain how osmosis affects living cells. Revise your practical work, too.1.8 Active transport (supplement)1.9 Enzymes (what they are and what they do)Make sure you know what an enzyme is, what it does and be able to describe and explain the effects of temperature and pH on enzyme reactions. Revise your practical work, too.1.10 Enzymes in seed germination, washing powders, the food industry and how we use enzymes in micro-organisms (supplement)Check you understand which enzymes are involved and what they do.Methods of summarisingTopic headings and key wordsIt is worth making a list of individual topics with minimal details under each heading; simply key words and key facts, with any relevant equations, units etc. If you were looking at chunk 3, your list or flash cards might look something like this:Respirationrelease of energy from nutrients in a cell oxidation of glucosehappens in all cellsAerobic respirationoxygen combined with glucoseglucose + oxygen carbon dioxide + waterlots of energy releasedAnaerobic respirationglucose broken down without oxygenglucose lactic acid (humans)glucose ethanol + carbon dioxide (yeast and plants)less energy released than with aerobic respirationused in brewing and bread-makingGas exchangediffusion of oxygen into and carbon dioxide out of an organismgas exchange surfaces thin, large surface area, good blood supplyhuman gas exchange system trachea, larynx, bronchus, bronchioles, alveoli, lungs, pleural membranes diaphragm, intercostal muscleslabelling these on a diagramBreathingbreathing in diaphragm and external intercostal muscles contractbreathing out both sets of muscles relaxcontraction of muscles pulls diaphragm down and rib cage up increases volume in thoraxthis produces a lower pressure so air moves in from higher pressure outsideand so onThe process of doing this summary is a really good way of getting your brain to think hard about what you need to know, which in itself is very useful revision. Its much better than just learning things from a revision guide, where someone else has done the summarising.Mind threadsIn science there are often threads that run through large sections, where a true understanding can only be gained by seeing the thing as a whole. By drawing a simple diagram we can get a complete visual picture, which will help your understanding as well as your memory. Sometimes these threads will cover more than one of our chunks. For example, think about how muscle contraction links up with respiration, breathing and heart rate:You could make even more links than this. For example, you could include breathing rate and temperature regulation because muscle contraction generates heat and the way that extra carbon dioxide in the blood causes an increase in breathing rate. You could include anaerobic respiration, and how glucose gets into the blood (diet and digestion link in here). And what about adrenaline?The most useful thing about these mind thread diagrams is the process of putting them together. Making your brain work out the links will help you to remember the information.How long should I spend revising?You are far better off doing a sensible amount of quality revision than hour after hour of meaningless reading. Lots of people find they cannot concentrate for periods of much more than 20 minutes. If that is you, then take a short break every 20 minutes; make a cup of tea or get some fresh air for a few minutes before going back to your work.After about an hour and a half take a longer break of at least fifteen minutes, and do something completely different. Other people find they work best by settling down to concentrate for a longer period say 45 minutes when they think only about their work and nothing else, and then take a longer break.If yo