DP Biology (last assessment 2024)

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Question 23M.3.HL.TZ1.24

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Date May 2023 Marks available [Maximum mark: 6] Reference code 23M.3.HL.TZ1.24
Level HL Paper 3 Time zone TZ1
Command term Explain Question number 24 Adapted from N/A
24.
[Maximum mark: 6]
23M.3.HL.TZ1.24

Athletes may take growth hormone to build muscle mass and improve performance. Explain the action of peptide hormones, using growth hormone as an example.

[6]

Markscheme
  1. growth hormone is produced by the pituitary gland;
  2. hormone travels in blood plasma to the target organ/muscle;
  3. (peptide) hormone binds to receptor/protein on the surface of the cell;
  4. triggers cascade/series of reactions inside cell;
  5. reactions mediated by secondary messengers;
  6. secondary messengers allow amplification of the signal from the hormone;
  7. cascade can involve activating/inhibiting enzymes;
  8. secondary messengers cause a specific cell response in the nucleus of the cells
    OR
    trigger gene expression;
  9. growth hormone stimulates protein synthesis/mineralization of bone/increase in cartilage cells;

Do not accept increase muscle mass or performance as that is in the stem.

Examiners report

This was answered more poorly than expected. Those that did know about peptide hormones were able to get four or more marks. Unfortunately, some were distracted by the mention of growth hormones used by athletes in the stem so did not explain peptide hormones as required but focused on the use of growth hormone or even steroids by athletes instead. Others had no idea what peptide hormones were and instead focussed on peptides.