Tagged: IGCSE

IGCSE Biology 2017 paper 2 predictions

This post starts with a massive proviso of course.  Making predictions as to which topics might appear in a future exam is a very risky business.  The paper 2 you will all sit after half term can test material from the entire specification (including all the specification points in bold) and there is absolutely no guarantee that topics tested in paper 1 may not reappear in some form in paper 2.

So the proviso is this:  the only way to be fully prepared for paper 2 is to revise the entire specification so that you are prepared for whatever the examiners might throw at you.

But having said that, it seems sensible to focus your revision for paper 2 onto topic areas that were not examined in paper 1.  If I were in your position, these are the topic areas for which I would be doing most of my revision in the coming weeks:

  • Respiration 2.33 – 2.37
  • Gas exchange in Plants 2.38-2.43
  • Transport in Plants 2.49 – 2.56
  • Transport in Humans 2.57 – 2.66
  • Kidney 2.68 – 2.76
  • Reproduction 3.1 – 3.12
  • Food Chains and Energy Flow 4.4 – 4.7
  • Nitrogen and Water Cycles 4.8, 4.10
  • Human Influences on Environment 4.11 – 4.17
  • Food Production (including fish farming) 5.1 – 5.9
  • Selective Breeding and Genetic Modification 5.10 – 5.16

The bad news is that this list above still forms a large proportion of the extensive EdExcel IGCSE Biology specification but the good news is that there are PMGBiology blog posts on all the above.  So please use the search function on my homepage to find material to help you revise.

Practice papers and mark schemes are available online (and for my students on the school Firefly page)

Keep working hard – you are almost there and the summer to come will be long and restful….

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Final advice before iGCSE Biology paper 1 on Tuesday

Well we are nearly there….. 24 hours to go until the main IGCSE Biology exam (worth 120 of the total 180 marks).  I hope you are all excited and looking forward with optimism to being able to show the examiner how much you understand from the extensive specification.  What should you be doing in this final 24 hours?

The most important thing is that you all get a good night’s sleep tonight.  Please do not stay up late cramming -it does not work! The evidence base for this is completely clear: you will perform better tomorrow with a normal night’s sleep tonight.  So please stop work an hour before you intend to go to bed, relax for an hour watching TV or socialising and then go to bed……

This afternoon you should want to look over a paper or two to familiarise yourself with the kinds of questions and the mark schemes.  I would have a final look again at the summer 2015 and summer 2016 paper 1B scripts.  Look at your answers and the kind of ways you lost marks.   In particular focus on the longer answer questions (for 4,5 or 6 marks) and look at the mark schemes.  Often there are marks available for saying obvious things but only if the correct vocabulary is used correctly.

Remember the PMG list of banned words:

Amount (oh no, please don’t ever write this in an exam – think – do you mean mass/volume/concentration?)

Level (do not talk about the level of something, you always mean “concentration” and concentration is a noun that actually means something!)

Substance – what substance are you talking about?  oxygen? glucose?

Gases – in questions on gas exchange or transport, please do not write about “gases” – say which gases you mean!

Nutrients – not really a banned word but one that needs very very careful use…..  A nutrient is a food molecule, for example glucose, an amino acid or a lipid. Nutrients like these are transported dissolved in blood plasma in mammals but if asked about it, don’t use the word but actually state which molecule you are talking about.  None of these nutrients are absorbed into the roots of a plant.  Plants absorb mineral ions (nitrate, phosphate, magnesium, potassium etc) through their roots into root hair cells by active transport.

Look over your revision notes a few final times to familiarise yourself with the key words.  Focus your final revision on the key areas that you know will definitely come up:  there will be a genetics question, there will be an experimental design question, the chances are that fish farming and fermenters will be there as usual……..

If you have worked hard for several weeks (and I know many of you have) you have little to fear in the exam from a lack of knowledge.  The thing to fear is losing marks due to rushing, due to not reading the question and due to not giving yourself time to think.  None of you will be rushed for time I promise, so please

keep-calm-and-read-the-question-14

  • read every word in every question
  • give yourself time to think before answering – even easy marks can be lost by rushing!
  • plan longer answer questions to make sure you cover all the key points using the correct jargon – think before you write anything, “what are the key terms in this topic?” – and then make sure you use them correctly in your answer

Good luck!  By the end of tomorrow you will have completed two thirds of your GCSE exams in Biology and that should be a happy thought……

IGCSE Biology paper 2 – predictions

I am always very wary of trying to “second guess” IGCSE examiners and predict what questions might come up as it can be a risky business.  But as all the Y11 students out there start a well-earned half term, I thought I would put up a short post with some suggestions as to areas of the specification that have not yet been tested.

Important Disclaimer:  Remember that the examiners can set questions on the entire specification in paper 2 (including all the bullet points in bold).  It seems more likely to me that the questions will be on areas of the specification not yet tested in paper 1 but you cannot guarantee it.  So please make sure you revise the entire specification and are as prepared as you can for any questions that might come up.

Topics not yet assessed on 2016 paper 1

  • Viruses 1.2
  • Enzymes and Biological Molecules 2.5, 2.6, 2.7, 2.8, 2.9, 2.10. 2.11
  • Movement across Membranes (Diffusion and Osmosis) 2.12, 2.13, 2.14, 2.15, 2.16
  • Photosynthesis 2.17, 2.18, 2.19. 2.20. 2.21, 2.22
  • Breathing 2.44, 2.45, 2.46, 2.47, 2.48
  • Respiration 2.32, 2.33, 2.34, 2.35, 2.36
  • Kidney and Excretion 2.68, 2.69, 2.70, 2.71, 2.72, 2.73, 2.74, 2.75, 2.76
  • Plant Responses 2.80, 2.81, 2.82
  • Reproduction in Plants 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7
  • Water/Carbon/Nitrogen Cycles 4.8, 4.9, 4.10
  • Food Production (crops) 5.1, 5.2, 5.3, 5.4
  • Food Production (microorganisms) 5.5, 5.6, 5.7, 5.8
  • Fish Farming 5.9
  • Genetic Modification 5.12, 5.13, 5.14, 5.15, 5.16

Remember that there are posts on almost all these topics on the blog so use the search function on the Home page and just type in the syllabus code.

Finally, keep working hard. It is easy to get too comfortable about your exams now that many have already been sat.  A little bit of fear is still a good thing, so remember that 33% of your GCSE marks are still up for grabs and this paper 2 will make all the difference in determining your final grade.  No short cuts now, keep being organised, methodical and diligent.  The summer holiday will give you plenty of opportunities to socialise, have fun and relax so try to keep the momentum up in this coming week.  Good luck!

Any questions, please ask by leaving a comment on this blog post.

F Revision for Michaelmas Trial 2015

You might like to make revision notes or cards to address the following questions…. If you managed this, you would be well prepared for your end of term exam.

1. Explain the difference in meaning between cell, organelle, organism, tissue and organ.

2. Understand the relative size of atoms, molecules, viruses, bacterial cells, animal cells, plant cells.

3. Draw two fully labelled diagrams one of an animal cell, one of a plant cell and describe clearly the differences in structure between the two.

4. Understand the structure and function of the following organelles: cell membrane, plant cell wall, nucleus, chloroplast, mitochondrion, sap vacuole, ribosome and also the function of the cytoplasm.

5. Explain why respiration is an important process in all cells.

6. What kind of processes in cells require energy from respiration?

7. Learn the word and balanced chemical equation for aerobic respiration.

8. Learn the word equation for anaerobic respiration in animal cells and in plants/fungi.

9. Describe the differences between aerobic and anaerobic respiration.  What is an “oxygen debt” and how is it repaid?

10. Describe the structure of the thorax (ribs, lungs, intercostal muscles, trachea, bronchi, bronchioles, alveoli, pleural membranes, diaphragm).

11. Understand the mechanism of breathing – both in and out – using diaphragm and the two sets of intercostal muscles.

12. Understand how alveoli are adapted for efficient gas exchange.

13. Understand the process of diffusion and examples of diffusion in living things.

14. Understand how surface area:volume ratios affect the rate of diffusion and why this might be significant for living organisms.

15. Understand the consequences of smoking on the lungs and circulatory systems.

16. Understand how the processes of respiration and photosynthesis interact in the leaves of plants. What is a compensation point?

17. Know the tissue structure of the leaf and the role of stomata in gas exchange.

18. How a leaf is adapted both for photosynthesis and also for gas exchange.

19. Understand the hydrogencarbonate indicator practicals and why different results are obtained in the various set up tubes.

Possible topics for IGCSE Biology paper 2 2015

Predicting the topics that might come up in an exam is always a risky business.  The most important thing to remember is that the examiners can ask questions on any topic at all in the paper 2 exam – this might include questions on topics they have asked already in the first paper .  The iGCSE specification is so large that it will be impossible for your understanding across the entire range to be assessed.

Having said that, I think it is sensible to focus your revision on topics that have not been assessed at all in paper 1.  My Head of Department has carefully been through the paper 1 (which I thought was an excellent exam by the way) and has come up with some suggestions as to what kind of questions might appear in paper 2.  (Note the important use of the word might…..)  Here is his list:

  • A question about blood, vaccination, pathogens, bringing in bacterial and viral structure, maybe comparing them to animal cells?
  • Something to do with enzymes, nutrients (monomers, polymers), some detail on elements of the digestive system that have not been covered?
  • Water uptake, osmosis, transpiration stream, potometers?
  • Photosynthesis biochemistry, maybe an experimental question, linking with respiration (hydrogencarbonate indicator experiment for example?)
  • Nervous system – reflex arc and eye structure and function are both ripe for a good question
  • Homeostasis question, on thermoregulation or kidney function
  • A question about cloning that links in with cell division, mitosis and meiosis, asexual versus sexual reproduction
  • Natural selection, evolution, selective breeding, maybe linked to an environmental context (e.g. global warming), or food production (e.g. fish farming)
  • Food webs and energy flow, along with a carbon/water/nitrogen cycle component
  • A respiration question that ties in with yoghurt and/or beer production

I think this is a really sensible list and a good way to start your revision for paper 2 in June.  Look at each of these topics carefully, make sure you understand the details in the specification and then have a go at past paper questions on each of these subject areas.  I will try to get some new blog posts up that address these bullet points in the next week or two (fingers crossed…)  There is already quite a lot in the blog if you use the “Search PMGBiology” function at the top of the home page.

Good luck and keep working hard!

Final advice before iGCSE Biology paper 1 tomorrow

Well we are nearly there….. 24 hours to go until the main IGCSE Biology exam (worth 120 of the total 180 marks).  I hope you are all excited and looking forward with optimism to being able to show the examiner how much you understand from the extensive specification.  What should you be doing in this final 24 hours?

The most important thing is that you all get a good night’s sleep tonight.  Please do not stay up late cramming -it does not work! The evidence base for this is completely clear: you will perform better tomorrow with a normal night’s sleep tonight.  So please stop work an hour before you intend to go to bed, relax for an hour watching TV or socialising and then go to bed……

This afternoon you should want to look over a paper or two to familiarise yourself with the kinds of questions and the mark schemes.  I would have a final look again at the summer 2013 and summer 2014 paper 1B scripts.  Look at your answers and the kind of ways you lost marks.   In particular focus on the longer answer questions (for 4,5 or 6 marks) and look at the mark schemes.  Often there are marks available for saying obvious things but only if the correct vocabulary is used correctly.

Remember the PMG list of banned words:

Amount (oh no, please don’t ever write this in an exam – think – do you mean mass/volume/concentration?)

Level (do not talk about the level of something, you always mean “concentration” and concentration is a noun that actually means something!)

Substance – what substance are you talking about?  oxygen? glucose?

Gases – in questions on gas exchange or transport, please do not write about “gases” – say which gases you mean!

Nutrients – not really a banned word but one that needs very very careful use…..  A nutrient is a food molecule, for example glucose, an amino acid or a lipid. Nutrients like these are transported dissolved in blood plasma in mammals but if asked about it, don’t use the word but actually state which molecule you are talking about.  None of these nutrients are absorbed into the roots of a plant.  Plants absorb mineral ions (nitrate, phosphate, magnesium, potassium etc) through their roots into root hair cells by active transport.

Look over your revision notes a few final times to familiarise yourself with the key words.  Focus your final revision on the key areas that you know will definitely come up:  there will be a genetics question, there will be an experimental design question, the chances are that fish farming and fermenters will be there as usual……..

If you have worked hard for several weeks (and I know many of you have) you have little to fear in the exam from a lack of knowledge.  The thing to fear is losing marks due to rushing, due to not reading the question and due to not giving yourself time to think.  None of you will be rushed for time I promise, so please

keep-calm-and-read-the-question-14

  • read every word in every question
  • give yourself time to think before answering – even easy marks can be lost by rushing!
  • plan longer answer questions to make sure you cover all the key points using the correct jargon – think before you write anything, “what are the key terms in this topic?” – and then make sure you use them correctly in your answer

Good luck!  By the end of tomorrow you will have completed two thirds of your GCSE exams in Biology and that should be a happy thought……

Feedback on Zondle revision test 3

There were some difficult questions in this quiz tonight and all the players who scored more than 20 out of 30 were doing really well I would say.  The questions were meant to provoke thinking and to be stimulating for you rather than all being simple recall of facts.  I want to draw your attention to a few of the main ideas.

1) Antigen is a difficult term to define and students often confuse it with the similar word antibody.  Antigens are proteins on the surface of an invading pathogen that can trigger an immune response.  (For the sake of completion, antibodies are proteins secreted by B lymphocytes/plasma cells that can bind to antigens and so help eliminate them from the body)  Have a look at my blog post on immunity which can be found by searching using the tag cloud.

2) This blog post on immunity will also answer the question about why someone can never suffer from the disease measles more than once.  Remember this cannot be due to antibodies remaining in the blood stream after the first exposure.  I had measles as a 5 year old but all the antibodies produced in this primary response would have disappeared before my 6th birthday.  But I will be protected from measles for the rest of my life because of the memory cells I made all those years ago.

3) Very few players knew that malaria was a disease caused by a protistan parasite.  This is disappointing as it is a straightforward factual recall and the Plasmodium parasite for malaria is specifically mentioned in the specification in the section on Five Kingdom classification.

4) Almost everyone got almost all of the digestion questions correct so there is little to add here.

5) I put a few tricky questions on the menstrual cycle into the quiz.  Now I do know that the hormones FSH and LH are not specifically mentioned and it is actually unlikely that you will be asked on them.  But if you are to understand the menstrual cycle to an A* level, you cannot do this without an appreciation of the four hormones that regulate reproductive function:  FSH, LH, oestrogen and progesterone.

I will try to write a post for you all on menstrual cycle just to top up your understanding.  Keep your eyes on this blog during the week…..

6) The question about which molecules can be made by a plant in photosynthesis was a bit of a trick question – please accept my apologies.  The thing I would like you to appreciate is that photosynthesis doesn’t just make glucose (or the storage polymer starch) but actually makes all the biomolecules in the plants’ cells.  Glucose, starch, amino acids, proteins, fats, vitamins and DNA are all made by the plant in photosynthesis.  (This is yet another reason why the equation that you have to learn for photosynthesis cannot be 100% correct)

7) There were then a few questions on the kidney.  Remember if you are ever asked in any context about the movement of water into or out of cells, there is only mechanism by which this can happen.  Water never moves by diffusion and is never pumped into or out of cells by active transport.  The only mechanism ever for water movement across a cell membrane is via osmosis.

8) Nitrogen cycle often catches people out.  It is a vital topic to revise and understand fully as often questions on it can be superb A* discriminator questions.  Learn the four types of bacteria that are involved – my two blog posts on the subject should be a help.

Any more questions/comments/queries, please comment on this post and I will get back you asap.

 

Questions and Answers for iGCSE Zondle Biology revision challenge 1

I know that some people were not able to see the correct answers after each question during the game today.

Zondle challenge 1 Q&A

The attached pdf file should show all 30 questions, the correct answers and the three incorrect answers for each question.  I hope that this pdf together with the commentary on the game will be helpful for revision for the people who played.

Next revision challenge for iGCSE Biology will be on 22-4-2015 at 2100 BST.  I hope many of you will sign up again.  New topics, new questions and lots to learn…..

Commentary on Zondle GCSE Biology Revision challenge 1 questions

I hope that those of you who played the GCSE Biology revision challenge this afternoon enjoyed the process.  I would welcome comments on this blog post along the lines of www (what went well) and ebi (even better if)….

The questions were grouped into several topic areas.

Questions 1 to 4 were on thermoregulation.  Understanding vasoconstriction, vasodilation and sweating are the key things here and if you haven’e done already, I would read my blog post on this topic.

https://pmgbiology.wordpress.com/2014/05/29/skin-a-understanding-for-igcse-biology/

Questions 5 – 9 were on plant transport and these were well answered by almost all players.  Remember that phloem sieve tubes move sucrose and amino acids around the plant.  Water and minerals are transported in xylem vessels of course, but the other distractor answers included various polymers (starch and proteins) that are made in photosynthesis in the leaves but which are too large and insoluble molecules to be transported in phloem.

Questions 10-15 were all on the bacteria in the Nitrogen cycle.  This is a tricky topic but one that rewards patient work by candidates to master it. In reality the Nitrogen cycle is not difficult to understand but it is easy to muddle the names and roles of the four types of bacteria involved.  Again there are a couple of blog posts on Nitrogen cycle that I would encourage you to read….

https://pmgbiology.wordpress.com/2014/04/12/bacteria-of-the-nitrogen-cycle-a-understanding-for-gcse-biology/

https://pmgbiology.wordpress.com/2014/04/12/nitrogen-cycle-for-igcse-biology/

Questions 16-23 were on digestive systems.  These were generally well answered although many players didn’t appreciate that peristalsis doesn’t just happen in the oesophagus: it is the process that moves the food along the entire length of the gut tube from top of oesophagus to the end of the rectum.  The role of the lacteal in transporting fatty acids and glycerol away from the villi in the small intestine is also one of the trickier topics here.  Amino acids and sugars diffuse into the blood capillaries in the villus but fatty acids and glycerol (the products of digestion of lipids) don’t go into the capillaries but instead into a separate vessel called a lacteal. This forms part of the lymphatic system and the liquid formed ends up back in the blood but effectively bypasses the liver, preventing the cells in the liver being overloaded with fatty acids following a fatty meal.

Questions 24-29 were on the heart and circulation.  There were quite a few incorrect answers here but perhaps this was because enthusiasm levels were dropping….  The flow of blood through the heart is an important topic to appreciate – into RA through vena cava, then into RV through right AV valve, then into PA through semilunar valve, then to lungs, back from lungs in pulmonary veins, into LA, through Left AV valve into LV, then into aorta through the aortic semilunar valve…..

The heart strings in the heart (chordae tendinae) are commonly misunderstood.  They play no role at all in opening or closing the AV valves (this is done simply by the balance of blood pressures in atrium and ventricle) but do provide tension to stop the valve “blowing back” and thus opening when the ventricle contracts.  Have a look at pictures of a real heart dissection to see that these tendons attach to the valve flaps and ensure they cannot blow open when the pressure in the ventricles rise during ventricular contraction.  Ask me for more detail if this doesn’t make sense.

Controlled experiments: what do examiners mean? A* understanding for iGCSE Biology

There are several specification points in the iGCSE syllabus that mention controlled experiments.  For example in the E Michaelmas work, there are two:

  • describe how to carry out simple controlled experiments to illustrate how enzyme activity can be affected by changes in temperature
  • describe simple controlled experiments to investigate photosynthesis showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll

So what exactly do they mean by a controlled experiment?

In an investigation you need to know what is meant by the independent variable and the dependent variable.  To put it in the simplest terms, the independent variable is the thing you are altering; the dependent variable is the thing you are measuring.

In any experiment there will also be a range of other variables that might affect the dependent variable.  For example in the first bullet point above, enzyme-catalysed reactions are not only affected by changes in temperature.  They can be affected by pH, by the concentration of enzyme and by the concentration of substrate.  A controlled experiment is one in which these other variables – now called control variables – are kept constant to ensure it is a fair test.  So if you were devising an experiment to investigate the effect of temperature on an enzyme reaction, make sure the pH is kept constant by using pH buffers and that the enzyme concentration and substrate concentration are exactly the same in every experimental set up.

It’s as simple as that…….