1. Type II diabetes is commonly observed in obese humans. Munc18c is a protein related to insulin-mediated glucose transport in skeletal muscle. A group of lean (BMI < 25) and obese (BMI > 30) individuals, all non-diabetic, fasted (had no food) for either 12 hours or 48 hours. Blood glucose concentration and skeletal muscle Munc18c protein content were measured at the end of the fasting period in each individual. The results are shown in the graph.
(a) (i) State how body mass index is calculated.
(ii) Identify the lowest Munc18c protein content in a lean individual after 48 hours of fasting.
(b) (i) Outline the relationship between blood glucose concentration and Munc18c protein content in obese individuals after 12 hours of fasting.
(ii) Compare the overall effects of fasting for 12 hours and 48 hours on the blood glucose concentration.
(c) Discuss the hypothesis that obesity is associated with reduced Munc18c protein content.
2. (a) Describe how the appetite control centre in the brain functions.
(b) Outline the impact of the deficiency of the following components of the human diet.
3. Food miles are included in the calculation of the total energy input used to produce foods and transport them to the consumer.The daily per capita total energy input to the US food system was calculated to be
- • 23.1 kJ for fats, sugars, snacks and baked goods
- • 12.6 kJ for meat and eggs
- • 8.0 kJ for fruit and vegetables
- • 3.4 kJ for whole grain cereals.
(a) State two problems caused by long distance food transport.
(b) Discuss the impact on the environment and human health caused by the consumption of foods with high and low total energy input.