Student Book Links

Student book links / Specification links / Link to AS specification / Suggested time allowed (includes contact and non-contact time):
·  1.1.15–16 / ·  4.1.3 (f)–(i) / ·  2.1.3 Alkenes / Four to five hours
Suggested teaching order
1.  The structure of a triol such as propane-1, 2,3-triol
2.  The structure of fatty acids such as hexadecanoic acid
3.  The formation of an ester (triglyceride) from the above compounds
4.  Saturated and unsaturated fats
5.  Cis and trans unsaturated fats
6.  The comparative healthiness of unsaturated – especially trans – fats
7.  The increased use of fatty acid esters as biodiesel
Weekly learning outcomes
Students should be able to:
·  Describe a triglyceride as a triester of glycerol (propane-1,2,3-triol) and fatty acids.
·  Compare the structures of saturated fats, unsaturated fats and fatty acids.
·  Compare the structures of cis and trans isomers of unsaturated fatty acids.
·  Compare the link between trans fatty acids, the possible increase in bad cholesterol and the resultant increased risk of coronary heart disease and strokes.
·  Describe and explain the increased use of fatty acid esters as biodiesel.
Key words / How Science Works
Triester Low-density lipoprotein (LDL)
Triglyceride High-density lipoprotein (HDL)
Triol Cholesterol
Saturated Fatty acid
Unsaturated Stereoisomerism / ·  HSW 6b The link between unsaturated (especially trans) and saturated fats and current concerns about heart disease and obesity
·  HSW 7c The use of biodiesel as a fuel to increase contribution to energy requirements from renewable fuels
Learning styles (S = Starter activities, M = Main activities, P = Plenary activities) / ICT activities
Kinaesthetic
Activity S1
Activities M1–3
Activities P1&3 / Interpersonal
Activities S1–3
Activities M1–3
Activities P1–2 / Auditory
Activities S1–3
Activities M1–3
Activity P1–3 / Visual
Activities S1–3
Activity M1
Activities P2–3 / ·  Research the current views on fats as part of our diet and read an online article regarding cis and trans fatty acids in a population.
·  Research the use of fatty acid esters as biodiesel. Produce a 'for and against' PowerPoint presentation.
Suggested starter activities / Equipment / Teacher notes
1. Brainstorm: ’What do we know about fats in the diet’?
2. Revise AS work on saturated and unsaturated hydrocarbons. / This could be done as a quiz or test, written or oral.
3. Revise AS work on cis–trans (E/Z) isomerism. / This could be done as a quiz or test, written or oral.
Suggested main activities / Equipment / Teacher notes
1. Practical activity 7: Reactions of ethanoic anhydride and the synthesis of aspirin (acetylsalicylic acid) / See technician worksheet. / See teacher worksheet.
2. Give a presentation on healthy fats. / Whatever the students need – e.g. access to Internet, newspaper articles, etc. / This is an extension of the first ICT activity. Students work individually or in groups and can be given different points of view as their starting points. NB. This activity needs to be sensitive to the students in the class – hopefully, all the points in the learning outcomes above can be covered during this presentation.
3. ‘Biodiesel: beneficial or harmful to the environment?’ Hold a class discussion on this. / Whatever the students need – e.g. access to Internet, newspaper articles, etc. / This is an extension of the second ICT activity. This is currently very topical – initially seen as a good thing, but now seen as detrimental as cash crops grown instead of food crops. Many ethical issues – hopefully, all the points in the learning outcomes above can be covered during this discussion.
Suggested plenary activities / Equipment / Teacher notes
1. Hold a class debate on the presence of fats in a healthy diet. / Can be linked to the first ICT activity. Different students represent polar viewpoints such as: all fats are bad; unsaturated fats (poly or mono) are not so bad; trans unsaturated are positively good for you, etc. The discussion should include saturated, and cis and trans unsaturated fats.
2. Give PowerPoint presentations on biodiesel (see second ICT activity above). / This could be done as part of the preparation or summary for Activity M3.
3. Play Name it! / Cards with structures of triesters, fatty acids and triols – some could be skeletal or other types of structure. / Students take turns at naming the structure – individually or in groups.
Homework suggestions
·  How many C=C bonds are there in a molecule of C17H35COOH? How many straight-chain structural isomers are there for this formula? Draw and name one pair of cis–trans isomers for this formula.
·  Check your fridge. Do your margarines or other fat-containing foods give helpful data about the types of fat they contain?
Cross-curriculum links
·  Food technology – fats
·  Biology – fats and lipids
Stretch and Challenge
·  Research and do a presentation on LDL and HDL cholesterol.
·  What is the role of fatty acids in soap-making?
·  Measure the degree of unsaturation in a sample of fat by reacting with iodine.
Potential misconceptions
·  Healthy eating guides lead many students to think that all fats are bad and should be completely excluded from our diets – the research undertaken here should show them otherwise!
Notes