(i) Using the nomogram, state the lower weight limit for a woman with the height of 155 cm who is classified as overweight, giving the units.

Lower weight limit: .........................................................

(ii) State a major health problem of the circulatory system that is correlated with obesity.

Draw the structure of a saturated fatty acid.

Describe how the hormone leptin helps to prevent obesity.

(i) 60 kg Units required.

(ii) coronary heart disease or coronary artery disease or thrombosis or stroke or hypertension or high blood pressure or atheroma or
fatty deposits in arteries or plaque «in arteries» or arteriosclerosis or atherosclerosis

[CH₂]_n / hydrocarbon chain with single bonds and at least four carbons

COOH head at one end AND three hydrogens on other end

The minimum of four carbons includes the end of the hydrocarbon chain and the COOH group.

Hormone produced by adipose/fat cells/adipose tissue. Reject produced by fat. Reject produced by pituitary.

Acts on/target cells are in the hypothalamus «of the brain»

Inhibits/reduces appetite/hunger
OR
causes feeling of satiety
OR
makes you feel full

More leptin with more adipose tissue/fat «storage» tissue/cells

Eat less/decreases/reduces food intake/in humans obese people can have leptin resistance

(i) Teachers expressed fears in G2 forms that candidates would be unable to use the nomogram through unfamiliarity. In fact most candidates successfully read off the value as instructed.

(ii) Many candidates could name a health problem of the circulatory system correlated with obesity, but vague terms, such as clogged arteries, were not allowed.

This was generally well answered. Most candidates showed a saturated hydrocarbon chain correctly and many also showed the carboxyl group.

Despite the fact that the hormone leptin is a new concept in the syllabus many candidates were able to answer this question accurately. In weak answers there was some confusion over the origin of leptin and its role.