Category: General

How to answer multiple choice questions: a quick guide

Many of the students I teach are facing end-of-term exams next week.  And for my Y9 and Y10 students these are multiple choice papers which pose a different challenge to the more usual structured answer format.  So here is a quick PMG guide to help you score the highest mark you can on this kind of paper.  Good luck!

1) Don’t underestimate the opposition!

The biggest mistake students make with these exams is to be over-confident.  The reason GCSE exams no longer contain any multiple choice questions is because it was felt that this type of question is too difficult.  The examiner, by selecting four incorrect responses to every question, is trying to catch you out and the more plausible the incorrect responses, the better the question!  So your understanding needs to be really good to not be tricky by these underhand tactics…. Get revising!

2) Read the question carefully.

This skill is tested even more fully in a multiple choice exam. You spend less time writing answers (obviously), so this allows more time for reading and thinking.  Even with a “mark a minute” time frame, there is time for thinking and planning before deciding on a correct answer.  Write on the question paper, use it for rough work and planning.  And RTQ carefully – with many similar but incorrect answers on the page, it is so easy to decide too quickly what the correct response is and so miss out on marks you could obtain with a little more care.

3) Try to eliminate the obviously incorrect answers:  this will mean you are only focussing your thinking on the possibles.  It also means if you have to guess, you are maximising your odds of being lucky!  But be careful….. This strategy has an obvious flaw so be careful in what you eliminate.

4) Your best chance of getting a question right is the first time you answer it. So I suggest you leave blank any answers you are unsure of on your first go through the paper.  Don’t spend more than a minute on any question on this first pass through the paper.  You can come back to look at the harder questions at the end of the exam.  It is much harder in an exam to spot an error in a question you have already answered, so I would leave answers blank unless I am sure I am right….

5) Keep an eye on the time.  After 20 minutes of the exam, check that you are ahead of the time.  Most multiple choice exams are a “mark a minute” but I know that in our internal exams this isn’t always the case, so check.

6) Finally, make sure you answer every question.  There is only positive marking in these exams so you should always guess (see point 3 above).  The only way you can guarantee you won’t get a mark is if you leave the question blank!

Take a pencil and a rubber to these exams – both will be useful!  And good luck……..

Comments and Suggestions welcome…..

Dear Readers,

Please feel free to send me any comments/suggestions/improvements so I can make this blog better and more useful to the GCSE students who read it…..  I will be writing some new posts in the Christmas holidays to complete the current IGCSE specification, and perhaps then to address the new material included for examination in 2019….?

But please tell me if there are particular topics you would like me to expand on…. If you don’t understand it fully, then lots of other readers won’t either!

And keep working hard – no short cuts in Biology GCSE…..

Please click the “Leave a Comment” link below this post to pass on any feedback.

Air Pollution part 2: Grade 9 Understanding for IGCSE Biology 4.12

It’s a cold February day in half term as I write this and I have already lit my log-burner in the living room downstairs.  When this was fitted a year or two ago, I was told it is now a legal requirement in the UK to also fit a detector for one atmospheric pollutant that can be produced as a waste product of combustion of biofuels.  This post is about that pollutant, carbon monoxide.

Carbon Monoxide

Carbon monoxide is a colourless, odourless gas.  It is produced whenever carbon-based fuels (coal, gas, wood, charcoal) burn in an atmosphere with a restricted oxygen supply.  The structure of a molecule of carbon monoxide is very simple:  it is a carbon atom covalently bonded to a single oxygen atom.

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(My log burner has a control where you restrict air getting into the stove so that your massively expensive logs burn a little more slowly – hence the need for the CO detector)  Carbon Monoxide poisoning results in 200 hospital admissions per year in the UK and around 40 deaths.

Why is carbon monoxide such a deadly gas?

The symptoms of carbon monoxide poisoning are similar to flu.  Tiredness, vomiting, headache, stomach pain….  They are caused because when carbon monoxide is breathed in, it will diffuse into the blood in the alveoli of the lungs.  Carbon monoxide binds to haemoglobin, the protein found in red blood cells that transports oxygen.  It binds about 70 times as effectively to haemoglobin, forming a stable compound called carboxyhaemoglobin.  So it prevents haemoglobin molecules from transporting oxygen (and indeed carbon dioxide) around the body.

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I hope that post is useful when you come to revise this section.  It also links in of course to the topic on blood and indeed the health consequences of cigarette smoking.  I’m sure I have posts on these topics as well to read if you are interested…..  I’m off now to get my chimney swept and to check the batteries in my Carbon Monoxide detector.

Digestion of Lipids: Grade 9 Understanding for IGCSE Biology 2.29 2.30 2.31

A balanced diet will contain many different fats and oils.  The commonest type of molecule in these lipids is called a triglyceride.  They are made from a small molecule of glycerol attached to three fatty acids.

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These triglycerides are too large to be absorbed in the small intestine (ileum) and so need to be broken down into their constituent parts.  In the digestive system there are enzymes called lipases that can catalyse the digestion of lipids into fatty acids and glycerol.

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Most digestion of lipids happens in the duodenum.  The pancreas produces a lipase enzyme that mixes with the food in the duodenum.  Although bile does not contain any digestive enzymes, it does have bile salts that play an important role in the digestion of lipids.  Bile salts cause large fat droplets in the duodenum to change into many smaller lipid droplets – a process called emulsification. (Read my post on bile if you want more details here….)

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Fatty acids and glycerol molecules are small enough to cross the epithelium in the villus in the ileum.  This absorption of fatty acids and glycerol is slightly different to the other products of digestion as they do not pass immediately into the blood.  They are assembled immediately into structures called chylomicrons and these move into the single, blind-ended tube in the villus called a lacteal.  The lacteals merge together into lymph vessels that eventually empty into the blood in the neck.  (Please read my post on absorption in the small intestine to read more about this)

Spectre: **** but not quite the perfect *****

A few breakfast thoughts about “Spectre”…. No spoilers I promise.

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Sam Mendes continues to probe the Bond backstory in this excellent film.  The film contains enough references to some of the earlier works to keep even a true “Bond-nerd” like me happy.  There are small nods to Live and Let Die, OHMSS, From Russia with Love, ThunderBall and others all cleverly woven into a totally preposterous new story.  I felt that whereas Skyfall felt like something new for Bond, this film is very much meant as a return to the core values of the franchise:  exotic locations, cinematography, beautiful cars, a gorgeous female lead, black tie and ball gowns, Martinis.  There is even a villain with a white cat.

If Skyfall proves to be the high water mark of Bond (it is still my favourite Bond movie to date) then Spectre falls in only just behind.  Daniel Craig gives a superb performance of a cold, damaged man but still with an occasional warm glint in his eye.  He is ably supported by three great performances by the actors playing M, Q and Moneypenny.  All three hold the screen, Q in particular having the best one-liners and now even an action sequence in a mountain-top alpine health clinic.  The French actress Lea Seydoux playing the female lead is certainly a match for Bond on screen and the best scenes in the film are once she gets involved.  Her character like Bond’s has been damaged by life, her acting is great and she is certainly beautiful, very, very beautiful.

So why not 5 stars?  Well it comes down to just one thing.  Plot.  I know that having one that is terrible is also in the spirit of the earlier films but the plot here is so ludicrous, and the character of the villain so unexplained and unexplored that I could not give this the highest rating.  Blofeld is a cartoon baddy of course and the actor does his best with what he is offered, but the silliness of the story prevents this being a truly great film.  For me, Spectre also lacks the spine-tingling moments that made Skyfall so amazing.  I always shiver when the old DB6 appeared behind the garage doors and even its customary appearance here failed to make my hairs stand on end.  Indeed this is perhaps the main problem with this film – beautifully acted, great cinematography and locations but where are those special moments that make you smile inside?

Last few IGCSE Biology blog posts on their way…

I am very close to having a comprehensive coverage of the EdExcel iGCSE Biology specification on my site.  These are the last few topics I need to address:

  • Female Reproductive system
  • Mineral Ions in Plants
  • Human diet
  • The Digestive System in Mammals
  • Small Intestine
  • Comparison between Sexual and Asexual reproduction
  • Cell Division
  • Use of Quadrats
  • Air pollution and Climate Change
  • Deforestation
  • Microorganisms and Food Production
  • Growing Crop plants
  • Fish farming
  • Cloning in Plants
  • Cloning in Animals

I hope that I can write the last few posts between now and Christmas.  Then I can focus again on the common areas of confusion and poor understanding in the run up to iGCSE papers in summer 2016.