Question 23M.3.HL.TZ1.20
| Date | May 2023 | Marks available | [Maximum mark: 7] | Reference code | 23M.3.HL.TZ1.20 |
| Level | HL | Paper | 3 | Time zone | TZ1 |
| Command term | Compare and contrast, Describe, State, Suggest | Question number | 20 | Adapted from | N/A |
The level of cholesterol in blood can be used as an indicator of the risk of cardiovascular disease. The chart shows the incidence of coronary heart disease (CHD) per 1000 people aged between 40 and 59 years according to their serum cholesterol level.
[Source: Wong, N. and Levy, D., 2013. Legacy of the Framingham Heart Study: Rationale, Design, Initial Findings, and
Implications. Global Heart, [e-journal] 8(1), pp. 3–9. https://doi.org/10.1016/j.gheart.2012.12.001. Open access.]
Compare and contrast the effect on men and women of an increase in serum cholesterol.
[2]
- both have increased CHD with increasing cholesterol;
- men always higher incidence CHD than women at each level (of cholesterol);
Accept vice versa
This question was well-answered by almost all candidates as they were able to interpret the graph.
Suggest a reason for high total serum cholesterol not always being an indicator of CHD risk.
[1]
- depends on the type of cholesterol/ratio of HDL to LDL/some types of cholesterol do not increase the chance of CHD;
- may not indicate CHD if lack other risk factors for CHD;
However, very few candidates received a mark here. This question asked why high total cholesterol was not an indicator for CHD. Most answered about risk factors for CHD rather than considering what total cholesterol referred to and the fact that there are different types of cholesterol.
Describe the reactions that occur in the liver, leading to the production of bile.
[3]
- (excess) cholesterol is converted to bile salts;
- hemoglobin is broken down into heme and globin;
- heme is broken down to produce bilirubin and iron;
- bilirubin and bile salts combine to produce bile;
Many candidates did not get full marks for this question on reactions in the liver that result in bile formation, often confusing or combining changes that occurred in the liver. Often one mark was awarded for knowing that hemoglobin is broken down into heme and globin. Even those who did get full marks seldom mentioned that excess cholesterol is converted to bile salts and that these salts are what combine with bilirubin to produce bile.
State one long-term consequence of jaundice in newborn babies if this condition is not treated.
[1]
neurological/brain damage /deafness / cerebral palsy;
Very few could correctly give a long-term consequence of untreated jaundice in newborns. Most simply referred to yellow skin.