Question 23M.3.SL.TZ1.17
| Date | May 2023 | Marks available | [Maximum mark: 5] | Reference code | 23M.3.SL.TZ1.17 |
| Level | SL | Paper | 3 | Time zone | TZ1 |
| Command term | Deduce, Distinguish, Outline, State | Question number | 17 | Adapted from | N/A |
Newborn babies showing signs of jaundice can be treated with ultraviolet (UV) light. The graph shows the percentage decrease in blood serum bilirubin levels in these babies after 24-hour exposure to different ultraviolet (UV) light intensities.
[Source: Reproduced with permission from Pediatrics, Vol. 114, Pages 297–316, Copyright © 2004 by the AAP.]
Deduce the relationship between blood serum bilirubin levels and UV light intensity.
[1]
as UV light intensity increases, blood serum bilirubin decreases / negative correlation;
Candidates had to be careful here since the curve was positive but the y axis was a % decrease. Most candidates did recognise this.
State one long-term consequence of jaundice in newborn babies if this condition is not treated.
[1]
neurological/brain damage;
Do not accept death
Most answers referred to jaundice or death rather than brain damage.
Outline two ways in which blood nutrient levels are regulated by the liver.
[2]
- glucose stored as/released from glycogen;
- iron/copper/vitamin A/vitamin D stored/released;
- excess cholesterol/lipids broken down;
- excess protein/amino acids broken down;
Some candidates muddled liver and pancreas functions when referring to glucose/glycogen. Iron and cholesterol were often mentioned.
Distinguish between liver sinusoids and capillaries.
[1]
- sinusoids larger diameter than capillaries;
- sinusoids have gaps in the walls but capillaries do not;
- Kupffer cells only in sinusoids;
This was not often correctly answered; there were references to sinusoids being in the liver and capillaries elsewhere.