| Date | May 2015 | Marks available | 2 | Reference code | 15M.3.sl.TZ2.22 |
| Level | SL | Paper | 3 | Time zone | TZ2 |
| Command term | Discuss | Question number | 22 | Adapted from | N/A |
Question
Olive oil is a complex mixture of triglycerides, some of which are derived from oleic acid.
State the name of the compound which combines with fatty acids to form triglycerides.
Discuss two effects on health of consuming trans fatty acids such as elaidic acid.
Markscheme
glycerol / propan-1,2,3-triol;
Accept minor errors in naming, such as propane-1,2,3-triol.
hard to metabolize / accumulates in fatty tissue / difficult to excrete;
increases levels of LDL cholesterol / increases risk of heart disease;
Do not accept “increases level of bad cholesterol”.
Examiners report
Most students correctly identified glycerol as the compound which combines with fatty acids to form triglycerides. Students often described the difference between cis and trans isomer but did not always refer to the packing of the molecules. Many candidates knew one effect on health of consuming trans fatty acids with answers often referring to the greater risk of heart disease. Common incorrect effects on health of consuming trans fatty acids were that they were "difficult to break down" or "difficult to digest". These statements are not synonymous with trans fatty acids being "hard to metabolize".
Most students correctly identified glycerol as the compound which combines with fatty acids to form triglycerides. Students often described the difference between cis and trans isomer but did not always refer to the packing of the molecules. Many candidates knew one effect on health of consuming trans fatty acids with answers often referring to the greater risk of heart disease. Common incorrect effects on health of consuming trans fatty acids were that they were "difficult to break down" or "difficult to digest". These statements are not synonymous with trans fatty acids being "hard to metabolize".
