Deduce from the results of the study whether HGH improves strength.

Suggest one reason that it is difficult to detect illegal use of HGH to enhance athletic performance.

HGH is a peptide hormone. Describe the mode of action of peptide hormones on target cells.

the drug does not appear to improve strength as less mass can be lifted «by arms and legs» ✔

a. occurs naturally so hard to tell whether it has been injected ✔ 

b. HGH has very short half life ✔

a. peptide hormones do not enter the cell ✔

b. they bind to receptors/proteins in the plasma membrane of the target cell ✔

c. a secondary messenger initiates the cell response ✔

d. causes a cascade of actions that changes the cell’s physiology ✔

e. cAMP is a common secondary messenger ✔

While this was generally done well, those who missed this mark chose to write about muscle growth rather than the mass being lifted.

Students were unable to state that the detection of illegal use of HGH was due it already being naturally present in the body.

Although a few students still confused peptide and steroid hormones, many were able to score 2 or 3 marks here. Most of these students stated that peptide hormones do not enter the cell due to their hydrophilic nature, that they do bind to receptors on the cell membrane, and that this binding initiates a secondary messenger and causes a cascade of reactions. This level of detailed knowledge was not seen elsewhere in the paper. One possible reason for this is that peptide and steroid hormones have appeared frequently on recent exam papers, and that the use of past papers remains the most common way for students to prepare for these exams.