| Date | May 2013 | Marks available | 3 | Reference code | 13M.3.HL.TZ2.14 |
| Level | Higher level | Paper | Paper 3 | Time zone | Time zone 2 |
| Command term | Describe | Question number | 14 | Adapted from | N/A |
Question
Outline how bile helps in lipid digestion.
Describe how bile pigment is formed.
Markscheme
bile emulsifies/OWTTE lipids so enzymes can act on them
a. hemoglobin from the red blood cells is absorbed/phagocytosed in the liver/by Kuppfer cells;
b. hemoglobin is broken down into heme and globin groups;
c. iron is removed from the heme groups;
d. (residue from) heme becomes bilirubin/bile pigment (in hepatocytes);
Examiners report
This part was relatively easy for the candidates, but some missed some marks due to incorrect answers or lack of detail. We have seen non-hormone peptides in (a), no mention of stomach in (b), no enzymes in (c), and short cuts, inappropriate terminology (e.g. protein instead of globin) or misconceptions (e.g. heme is the bile pigment) in (d).
This part was relatively easy for the candidates, but some missed some marks due to incorrect answers or lack of detail. We have seen non-hormone peptides in (a), no mention of stomach in (b), no enzymes in (c), and short cuts, inappropriate terminology (e.g. protein instead of globin) or misconceptions (e.g. heme is the bile pigment) in (d).
