| Date | May 2016 | Marks available | 2 | Reference code | 16M.3.SL.TZ0.17 |
| Level | Standard level | Paper | Paper 3 | Time zone | TZ0 |
| Command term | Outline | Question number | 17 | Adapted from | N/A |
Question
Numerous health benefits are associated with diets that include omega-6 fatty acids and omega-3 fatty acids in a ratio between 1:1 and 4:1. When consumed in excess, omega-6 inhibits uptake of omega-3. Many people in developed countries eat large amounts of processed foods and oils, so they consume omega-6 fatty acids and omega-3 fatty acids at a ratio of between 10:1 and 25:1. Such high ratios are associated with many chronic diseases.
Deduce with reasons which two oils would be the best sources of fatty acids for a healthy diet.
Outline the meaning of the term essential when used to describe some fatty acids.
(i) State the name of the part of the brain where appetite is controlled.
(ii) State the role of the vagus nerve.
Markscheme
Canola AND flaxseed/walnut (Both needed)
Both have ratios within or close to recommended ratio
Fatty acids which have to be obtained in the diet
Fatty acids which cannot be synthesized in the body
(i) Hypothalamus (Do not accept appetite control centre)
(ii) Transmit impulses from brain to gland cells «in stomach»
Stimulate secretion by «stomach» gland cells
Stimulates secretion of gastric acid
Example of parasympathetic response eg: slows heart
Transmit sensory information to the brain
Examiners report
Generally well answered.
Generally well answered.
Generally well answered though a role of the vagus nerve caused some confusion.
