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Endocrine Systems — Free MYP5 Biology Practice Questions
1QuestionChemical signalingConcept Practice
2 marks~3 minCriterion D
During anaphylaxis, a life-threatening allergic reaction, the immune system releases histamine, causing widespread vasodilation, a dangerous drop in blood pressure, and bronchoconstriction. Adrenaline (epinephrine) is the first-line emergency treatment.
a
Outline how adrenaline reverses the physiological effects of anaphylaxis. [1]
b
Discuss one ethical issue associated with the use of adrenaline auto-injectors (EpiPens) in emergency medicine. [1]
Solutions
2QuestionChemical signalingAssessment Practice
3 marks~5 minCriterion C
The graph shows blood glucose and insulin concentrations in a healthy individual over 180 minutes following a meal. At time 0, glucose is approximately and insulin is low. Glucose peaks at approximately at 30 minutes, returning to baseline by 120 minutes. Insulin rises sharply after the meal, peaks at approximately 60 minutes, then returns to baseline by 150 minutes.
a
Describe the trends in blood glucose and insulin concentration between 0 and 180 minutes, referring to specific values from the graph. [1]
b
Explain how the endocrine system uses chemical signalling to return blood glucose to its baseline concentration after the meal. [1]
c
The insulin peak occurs approximately 30 minutes after the glucose peak. Analyse what this time delay suggests about the mechanism of hormonal regulation compared to nervous system regulation. [1]
Solutions
3QuestionChemical signalingAssessment Practice
4 marks~6 minCriterion A
During a stress response, adrenaline is released into the bloodstream and reaches all body cells simultaneously. A diagram shows adrenaline molecules arriving at both a liver cell and a muscle cell. The liver cell responds by breaking down glycogen and releasing glucose; the muscle cell shows no response.
a
State what structural feature a cell must possess in order to respond to a hormone. [1]
b
Explain why the liver cell responds to adrenaline while the muscle cell does not. [2]
c
Analyse what would happen to blood glucose regulation if muscle cells also expressed adrenaline receptors. Justify your reasoning. [1]
Solutions
4QuestionChemical signalingAssessment Practice
5 marks~8 minCriterion C
Rats underwent adrenalectomy (surgical removal of adrenal glands) and received daily cortisol injections at varying doses. Blood glucose was measured after 24 hours. The normal blood glucose range in rats is 80–120 mg/dL.
| Cortisol dose (mg/kg) | 0 (sham surgery control) | 0 (adrenalectomy + saline) | 2 (adrenalectomy + low) | 5 (adrenalectomy + medium) | 10 (adrenalectomy + high) |
|---|---|---|---|---|---|
| Mean blood glucose (mg/dL) | 110 | 65 | 82 | 105 | 120 |
a
Explain the role of cortisol in the hypothalamic-pituitary-adrenal (HPA) axis negative feedback loop. [1]
b
Analyse how the data from the adrenalectomy groups supports the conclusion that cortisol maintains blood glucose levels. [2]
c
Evaluate whether this experiment tests negative feedback regulation of cortisol, identifying two limitations of the experimental design. [2]
Solutions
5QuestionWorkingAssessment Practice
6 marks~9 minCriterion D
A pharmaceutical company proposes a synthetic estrogen-progestin hormone replacement therapy (HRT) for menopausal women. Clinical trials show the therapy improves bone density and reduces hot flashes, but is linked to a 25% increase in breast cancer risk over 10 years. Hormone metabolites entering wastewater cause feminisation of male fish, including vitellogenin production, threatening aquatic populations.
a
Explain two clinical benefits and one clinical risk of this HRT for menopausal women. [2]
b
Analyse how hormone metabolites entering wastewater systems affect aquatic organisms and their populations. [2]
c
Evaluate the long-term societal and environmental impact of this HRT, considering limitations of the clinical trial data. [2]
Solutions
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