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Human Body Systems

Human Body Systems — Free MYP5 Biology Practice Questions

1QuestionAntigen-Antibody InteractionsConcept Practice

2 marks~3 minCriterion B

A student investigates how temperature affects antibody–antigen binding. The relative binding strength of five antibodies is measured at two temperatures.

Antibody	A	B	C	D	E
Binding strength at 25°C (units)	45	62	38	71	54
Binding strength at 37°C (units)	42	58	35	67	50

Identify the pattern shown in the data by comparing the binding strength values at 25°C and 37°C for all five antibodies. [1]

Analyse what the data suggest about the relationship between temperature and antibody–antigen binding strength. [1]

Solutions

2QuestionAntibiotics, Resistance, and Public HealthConcept Practice

2 marks~3 minCriterion A

Penicillin is a widely used antibiotic that disrupts a specific structure found in bacterial cells but absent in human cells.

The diagram below shows a cross-section of a bacterium with structure X labelled.

Identify structure X. [1]

Explain why structure X makes an effective target for penicillin antibiotics. [1]

Solutions

3QuestionDefinition and Importance of HomeostasisConcept Practice

2 marks~3 minCriterion A

The diagram below shows a nephron from the human kidney, with structure X labelled at the point where blood is first processed.

Identify structure X. [1]

Explain how structure X contributes to maintaining fluid balance in the body. [1]

Solutions

4QuestionControl of Blood Glucose LevelsConcept Practice

2 marks~3 minCriterion A

The diagram below shows a pancreatic islet of Langerhans. Cell X is located at the periphery of the islet.

Identify cell X. [1]

State the hormone produced by cell X and explain how its release responds to a fall in blood glucose concentration. [1]

Solutions

5QuestionControl of Blood Glucose LevelsConcept Practice

2 marks~3 minCriterion A

The diagram shows a pancreatic islet. Cell X is smaller, more numerous, and clustered toward the centre of the islet. Cell Y is larger, less numerous, and located toward the periphery.

Identify cell X. [1]

Explain how cell X regulates blood glucose concentration when glucose rises above the normal range. [1]

Solutions

6QuestionBlood Vessels: Arteries, Veins, CapillariesConcept Practice

2 marks~3 minCriterion A

The cross-section below shows a blood vessel with a thick, muscular wall (tunica media) and a narrow lumen. Blood pressure in this vessel reaches approximately 120 mmHg during ventricular contraction.

Identify the blood vessel shown in the cross-section. [1]

Explain how the thick muscular wall enables this vessel to function effectively at high blood pressure. [1]

Solutions

7QuestionAccessory organsConcept Practice

2 marks~3 minCriterion D

In many countries, the demand for donor livers far exceeds supply. Patients with end-stage liver failure — where the liver can no longer detoxify the blood, synthesise proteins, or produce bile — face death without a transplant.

Allocation committees must decide who receives the few available organs.

State two functions of the liver that explain why complete liver failure is fatal without a transplant. [1]

Outline one ethical issue that arises when deciding which patient should receive a donor liver. [1]

Solutions

8QuestionAccessory organsConcept Practice

2 marks~3 minCriterion A

The diagram below shows the human digestive system with three organs labelled X, Y, and Z.

Identify the accessory organ labelled X in the diagram. [1]

Explain one reason why the liver is classified as an accessory organ of digestion rather than a primary digestive organ. [1]

Solutions

9QuestionCentral and Peripheral Nervous SystemConcept Practice

4 marks~6 minCriterion A

The diagram below shows a spinal reflex arc. A pin pricks the skin, generating a nerve impulse that travels through three neurons before reaching a muscle.

Identify the four labelled components of the reflex arc shown in the diagram. [2]

Explain the sequence of signal transmission from the moment the pin pricks the skin until the muscle responds, describing the role of each component identified in part (a). [2]

Solutions

10QuestionCommon diseasesConcept Practice

2 marks~3 minCriterion D

Tuberculosis (TB) is a bacterial respiratory disease transmitted via airborne droplets released when an infected person coughs or sneezes. In densely populated urban areas, close proximity between individuals significantly increases transmission risk. Public health authorities must balance disease control with the rights of individuals when designing intervention policies.

Explain how knowledge of TB's airborne transmission mechanism can inform the development of one specific public health policy in densely populated urban areas. [1]

Discuss one ethical issue that may arise when implementing TB control policies in urban communities. [1]

Solutions

11QuestionCommon diseasesConcept Practice

2 marks~3 minCriterion A

The diagram below shows a rod-shaped bacterium with a thick, waxy outer wall containing mycolic acids.

State the name of the disease caused by this bacterium. [1]

Explain one reason why the waxy cell wall makes this bacterium difficult to treat with standard antibiotics. [1]

Solutions

12QuestionCommon problemsConcept Practice

2 marks~3 minCriterion A

During intense exercise, skeletal muscle fibres are repeatedly stimulated, causing sustained contraction. A student examining an electron micrograph of a skeletal muscle fibre identifies structure X, the repeating unit bounded by two Z-lines.

Identify structure X. [1]

Explain how structure X shortens during muscle contraction. [1]

Solutions

13QuestionInteraction with other systemsConcept Practice

2 marks~3 minCriterion D

Outline ONE environmental impact shown or implied in the image of a region with high fluoride levels in drinking water, focusing on its effect on the skeletal system's interaction with other body systems.

Solutions

14QuestionCommon problemsConcept Practice

2 marks~3 minCriterion A

The diagram below shows a cross-section through the shaft (diaphysis) of a femur. An arrow points to the large central space within the bone.

Identify the structure indicated by the arrow. [1]

Explain one function of this structure. [1]

Solutions

15QuestionWorkingConcept Practice

4 marks~6 minCriterion A

The diagram shows the negative feedback loop that regulates blood glucose concentration in the human body.

Apply your knowledge of the endocrine system to answer the following questions.

Describe the sequence of events that occurs when blood glucose concentration rises above normal, beginning with detection by the pancreas. [2]

Explain how the release of glucagon restores homeostasis when blood glucose concentration falls below normal. Include reference to the role of the liver. [2]

Solutions

16QuestionChemical 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.

Outline how adrenaline reverses the physiological effects of anaphylaxis. [1]

Discuss one ethical issue associated with the use of adrenaline auto-injectors (EpiPens) in emergency medicine. [1]

Solutions

17QuestionAntibiotics, Resistance, and Public HealthAssessment Practice

2 marks~3 minCriterion A

A hospital reports increasing treatment failures after prescribing the same antibiotic for recurring Staphylococcus aureus infections. Laboratory analysis confirms the bacterial population has developed antibiotic resistance.

The diagram below shows a bacterial cell, including its chromosome and plasmid.

Explain how a spontaneous mutation in bacterial DNA can lead to antibiotic resistance. [1]

Explain how a resistance gene can spread rapidly between bacterial cells through horizontal gene transfer, referring to the role of plasmids. [1]

Solutions

18QuestionAntibiotics, Resistance, and Public HealthAssessment Practice

6 marks~9 minCriterion D

A farmer routinely adds low doses of antibiotics to the feed of healthy livestock to promote faster growth. This practice is widespread in industrial agriculture across many countries, though regulations vary considerably by region. Some nations have introduced partial bans, while others permit unrestricted sub-therapeutic use. Antibiotic residues are excreted by animals and enter surrounding environments through manure and agricultural runoff.

Explain how routine sub-therapeutic antibiotic use in livestock contributes to antibiotic-resistant bacteria entering the human food chain. [2]

Analyse the ecological consequences of antibiotic runoff from farms entering adjacent soil and water systems. [2]

Evaluate the effectiveness of current regulations governing agricultural antibiotic use, and propose one specific improvement. [2]

Solutions

19QuestionRole of White Blood CellsAssessment Practice

6 marks~9 minCriterion C

A patient with a bacterial infection has white blood cell counts (×10⁹/L) recorded over 14 days.

Day	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14
Neutrophils	4.0	7.5	12.0	15.0	13.0	10.0	8.0	6.5	5.5	5.0	4.5	4.2	4.0	3.8	3.5
Lymphocytes	2.5	2.0	1.5	1.0	0.8	1.2	1.8	2.2	2.5	2.8	3.0	3.2	3.5	3.8	4.0
Monocytes	0.5	0.6	0.8	1.0	1.5	2.0	2.5	2.8	3.0	3.2	3.5	3.8	4.0	4.2	4.5

Identify which white blood cell type peaks earliest and explain why this pattern is expected during a bacterial infection. [2]

Describe the trend in monocyte count over the 14 days and explain how this trend relates to their role in resolving the infection. [2]

The lymphocyte count falls from day 0 to day 4, then rises above its starting value by day 14. Analyse what this two-phase pattern reveals about the relative timing and nature of the innate and adaptive immune responses. [2]

Solutions

20QuestionComponents of the Immune SystemAssessment Practice

3 marks~5 minCriterion C

The graph shows the relative strength of the innate and adaptive immune responses over 14 days following pathogen entry into the body.

Describe the trend of the innate immune response shown in the graph. [1]

Explain why the adaptive immune response peaks later than the innate response. [1]

A patient with a genetic condition lacks functional B cells and T cells. Analyse how this would affect their ability to fight a pathogen over the 14-day period shown, compared to a healthy individual. [1]

Solutions

21QuestionAntibiotics, Resistance, and Public HealthAssessment Practice

2 marks~3 minCriterion D

In many countries, farmers routinely administer low doses of antibiotics to healthy livestock to accelerate growth and prevent disease outbreaks in crowded conditions. Resistant bacteria can then transfer to humans through the food chain, contaminated water, or direct contact with animals.

Outline one specific agricultural practice that involves antibiotic use. [1]

Explain the ethical conflict this practice creates for public health. [1]

Solutions

22QuestionAntibiotics, Resistance, and Public HealthAssessment Practice

4 marks~6 minCriterion A

The diagram below shows a simplified bacterial cell wall. Peptidoglycan strands — composed of alternating

N

-acetylglucosamine and

N

-acetylmuramic acid — are linked by short peptide bridges. The enzyme transpeptidase catalyses the formation of these cross-links. Penicillin molecules are shown binding to transpeptidase at the cross-link sites.

State the function of the bacterial cell wall. [1]

Explain how penicillin inhibits transpeptidase and prevents cell wall synthesis. [1]

Analyse how the inhibition of transpeptidase ultimately leads to bacterial cell death, referring to osmotic pressure in your answer. [2]

Solutions

23QuestionControl of Blood Glucose LevelsAssessment Practice

3 marks~5 minCriterion A

The graph below shows changes in blood glucose concentration and insulin secretion over 4 hours following a meal. Both variables are plotted against time (hours).

Describe the pattern shown by the two lines between 0 and 4 hours. [1]

Explain why insulin secretion increases when blood glucose concentration rises after the meal. [1]

A person with Type 2 diabetes shows a blunted insulin response: blood glucose rises to the same peak but takes significantly longer to return to the fasting level. Analyse how this delayed return is linked to the impaired insulin response shown on the graph. [1]

Solutions

24QuestionControl of Blood Glucose LevelsAssessment Practice

2 marks~3 minCriterion A

After eating a carbohydrate-rich meal, a student's blood glucose concentration rises above the normal range of approximately 4–6 mmol/L.

Describe the hormonal feedback loop that returns blood glucose to its normal range. In your response, use all of the following terms correctly: insulin, pancreas, beta cells, liver, glycogen. Present events in a clear, logical sequence. [2]

Solutions

25QuestionControl of Blood Glucose LevelsAssessment Practice

6 marks~9 minCriterion C

A diabetic patient consumes a meal containing 50 g of carbohydrates at time

0

minutes. On one occasion, an insulin injection is administered immediately after the meal; on another, no insulin is given. Blood glucose (mmol/L) is measured every 30 minutes for 3 hours.

Time (min)	0	30	60	90	120	150	180
Without insulin (mmol/L)	6	8	14	12	11	10	10
With insulin (mmol/L)	6	7	9	8	6	5	5

Describe the trend in blood glucose levels for each condition. [2]

Explain how the difference between the two data sets is consistent with insulin promoting cellular uptake of glucose. [2]

Evaluate the hypothesis that insulin lowers blood glucose by promoting cellular uptake of glucose, identifying one limitation of using blood glucose concentration as evidence for this mechanism. [2]

Solutions

26QuestionControl of Blood Glucose LevelsAssessment Practice

2 marks~3 minCriterion D

Insulin pumps are used in the management of type 1 diabetes. The device delivers a continuous low-level (basal) dose of insulin throughout the day, with additional bolus doses released at mealtimes in response to rising blood glucose levels.

State the role of insulin in restoring blood glucose levels to normal after a meal. [1]

Evaluate one limitation of using an insulin pump as a substitute for the body's natural homeostatic control of blood glucose. [1]

Solutions

27QuestionControl of Blood Glucose LevelsAssessment Practice

4 marks~6 minCriterion D

A diabetic patient wears a Continuous Glucose Monitor (CGM) that samples interstitial fluid every 5 minutes and sends real-time glucose readings and trend alerts to a smartphone. Traditional finger-prick testing provides only a single, momentary blood glucose value.

Explain one health benefit of CGM over finger-prick testing, linking your answer to the regulation of blood glucose levels. [1]

Explain one psychological impact — positive or negative — that continuous glucose data monitoring may have on the patient. [1]

Discuss the accuracy and limitations of CGM technology, and evaluate whether its overall benefits to a diabetic patient outweigh its drawbacks. [2]

Solutions

28QuestionBlood circulation (double circulation)Assessment Practice

3 marks~5 minCriterion A

The bar chart shows oxygen saturation (\%) in the pulmonary artery and pulmonary vein at rest and during moderate exercise.

At rest: pulmonary artery

\approx 75\%

, pulmonary vein

\approx 98\%

During exercise: pulmonary artery

\approx 40\%

, pulmonary vein

\approx 95\%

Calculate the difference in oxygen saturation between the pulmonary vein and pulmonary artery at rest and during exercise. [1]

State which vessel's saturation changes more between rest and exercise, and identify the physiological reason for this change. [1]

Explain why the difference in oxygen saturation between the pulmonary vein and pulmonary artery is greater during exercise than at rest. [1]

Solutions

29QuestionBlood Vessels: Arteries, Veins, CapillariesAssessment Practice

3 marks~5 minCriterion B

The table below summarises structural data for five blood vessels.

Vessel	Wall thickness	Lumen size	Valves	Direction of flow
Aorta	Very thick	Medium	No	Away from heart
Vena cava	Thin	Large	Yes	Toward heart
Pulmonary artery	Thick	Medium	No	Away from heart
Pulmonary vein	Thin	Large	Yes	Toward heart
Capillary	Very thin	Very small	No	Either

Identify the two structural features that consistently distinguish vessels carrying blood away from the heart from those carrying blood toward the heart. [1]

The renal artery carries blood away from the heart to the kidney. Deduce its wall thickness, lumen size, and whether valves are present. Justify your deduction by referring to the pattern in the data. [2]

Solutions

30QuestionBlood circulation (double circulation)Assessment Practice

2 marks~3 minCriterion A

The diagram below shows the human heart and lungs with one blood vessel labeled X.

Identify blood vessel X. [1]

Explain why blood vessel X is described as an artery even though it carries deoxygenated blood. [1]

Solutions

31QuestionBlood circulation (double circulation)Assessment Practice

6 marks~9 minCriterion C

The table below shows partial pressures of

O_2

and

CO_2

(mmHg) and haemoglobin saturation (\%) for four blood vessels in the human circulatory system.

Vessel	Pulmonary artery	Pulmonary vein	Aorta	Vena cava
$P_{O_2}$ (mmHg)	40	105	95	40
$P_{CO_2}$ (mmHg)	45	40	40	45
Haemoglobin saturation (\%)	75	98	97	75

Identify the vessel with the highest haemoglobin saturation and explain, using the

P_{O_2}

data, why saturation reaches this value at that location. [2]

Deduce the relationship between

P_{O_2}

and haemoglobin saturation, supporting your answer with two specific data comparisons from the table. [2]

Analyse how the data for all four vessels demonstrate that double circulation maintains efficient oxygen delivery to body tissues. [2]

Solutions

32QuestionBlood circulation (double circulation)Assessment Practice

5 marks~8 minCriterion C

A researcher measures blood oxygen saturation — the percentage of haemoglobin bound to oxygen — in each chamber of a resting mammal's heart, then repeats the measurements during moderate exercise.

Resting: right atrium 70%, right ventricle 68%, left atrium 96%, left ventricle 94%

Exercise: right atrium 62%, right ventricle 60%, left atrium 92%, left ventricle 90%

A fellow scientist proposes: "The left side of the heart always contains a higher oxygen saturation than the right side."

Compare the oxygen saturation values between the left and right sides of the heart at rest and during exercise. [2]

Explain the biological reasons for the difference in oxygen saturation between the left and right sides, making reference to the double circulation pathway. [2]

Evaluate whether the experimental data fully supports the hypothesis. [1]

Solutions

33QuestionBlood circulation (double circulation)Assessment Practice

2 marks~3 minCriterion D

Erythropoietin (EPO) is a hormone naturally produced by the kidneys. Some endurance athletes, including professional cyclists, have used synthetic EPO to enhance performance. Its use is banned by the World Anti-Doping Agency (WADA).

Explain how EPO affects the circulatory system to improve aerobic endurance performance, and identify and explain one ethical issue arising from its use in competitive sport. [2]

Solutions

34QuestionBlood circulation (double circulation)Assessment Practice

6 marks~9 minCriterion D

A hospital emergency department is trialling a rapid blood-typing device that analyses a finger-prick sample in 30 seconds with a 0.5% error rate (1 in 200 results is incorrect). Standard laboratory testing takes 45 minutes but has an accuracy of 99.99%. In a major trauma, every minute without a transfusion increases the risk of death from blood loss.

Explain why transfusing incompatible blood can be fatal, using the terms antigens, antibodies, agglutination, and haemolysis. [2]

Discuss the ethical trade-off between speed and safety when deciding which test to use in a life-threatening emergency. [2]

Evaluate whether the hospital should adopt the rapid device as its primary blood-typing method. In your answer, identify one specific limitation of a 0.5% error rate in this clinical context and suggest one strategy to reduce the associated risk. [2]

Solutions

35QuestionAbsorption in the Small Intestine and VilliAssessment Practice

2 marks~3 minCriterion B

Five small intestine samples were analysed for villus height and nutrient absorption rate.

Villus height (μm)	500	450	350	600	400
Absorption rate (mg/min)	8.0	7.2	5.6	9.6	6.4

Deduce the mathematical relationship between villus height and absorption rate, showing evidence from the data. [1]

A patient with coeliac disease has partially damaged villi, reducing average villus height to 275 μm. Using your relationship from (a), calculate the expected absorption rate and explain why the actual absorption rate in this patient is likely to be lower than your calculated value. [1]

Solutions

36QuestionAbsorption in the Small Intestine and VilliAssessment Practice

4 marks~6 minCriterion A

The diagram below shows a villus from the small intestine, with microvilli, a blood capillary network, and a lacteal labelled.

State the function of the microvilli on the surface of the villus. [1]

Explain how the blood capillary network within the villus maintains efficient absorption of glucose and amino acids. [2]

A student claims that fats could be absorbed directly into the blood capillaries rather than the lacteal, since both structures are present in the villus. Evaluate this claim. [1]

Solutions

37QuestionAbsorption in the Small Intestine and VilliAssessment Practice

2 marks~3 minCriterion A

The diagram shows a cross-section of a villus from the small intestine. Structures A, B, C, and D are labelled.

Identify structure C. [1]

Explain why fatty acids and glycerol enter structure C rather than the blood capillaries found in the same villus. [1]

Solutions

38QuestionAbsorption in the Small Intestine and VilliAssessment Practice

2 marks~3 minCriterion D

In coeliac disease, the immune system responds to gluten by damaging the lining of the small intestine, leading to a condition called villous atrophy.

Discuss how the structure and function of villi relate to both the diagnosis of coeliac disease and the ethical responsibility of hospitals to provide appropriate nutrition for affected patients. [2]

Solutions

39QuestionAbsorption in the Small Intestine and VilliAssessment Practice

5 marks~8 minCriterion C

Two segments of rat small intestine were prepared: Segment A (intact villi) and Segment B (villi mechanically removed). Each segment was placed in 100 mL of a

50 \, \text{mmol L}^{-1}

glucose solution at

37^\circ\text{C}

. Glucose concentration was measured every 10 minutes.

Time (min)	0	10	20	30
Segment A — glucose concentration (mmol L $^{-1}$ )	50	45	35	28
Segment B — glucose concentration (mmol L $^{-1}$ )	50	48	45	42

Describe the trend in glucose concentration for each segment over the 30-minute period. [1]

Explain how the structure of villi enables more efficient glucose absorption compared to intestinal tissue without villi. [2]

Evaluate whether this experimental evidence supports the hypothesis: "Villi increase the rate of glucose absorption in the small intestine." In your response, discuss the limitations of the experimental design. [2]

Solutions

40QuestionAccessory organsAssessment Practice

7 marks~11 minCriterion C

Blood samples from four patients were analysed for ammonia, urea, and albumin. Patient P1 is healthy; patients P2, P3, and P4 have liver dysfunction of varying types.

Ammonia ( $\mu$ mol/L)	P1 = 30	P2 = 120	P3 = 25	P4 = 140
Urea (mmol/L)	P1 = 5	P2 = 2	P3 = 1	P4 = 4
Albumin (g/L)	P1 = 40	P2 = 38	P3 = 35	P4 = 20

Analyse the data to describe the relationship between blood ammonia and urea levels as indicators of liver function. [2]

Deduce which liver process — deamination, protein synthesis, or both — is most likely impaired in each of patients P2, P3, and P4. Justify each deduction using the data. [3]

Discuss how impaired protein synthesis in the liver leads to low albumin levels and evaluate one consequence of this for whole-body fluid balance. [2]

Solutions

41QuestionCentral and Peripheral Nervous SystemAssessment Practice

5 marks~8 minCriterion A

When a person touches a hot stove, their hand withdraws before they consciously feel pain. A sensory neuron in the finger detects heat and carries a nerve impulse to the spinal cord. Inside the spinal cord, the signal synapses with an interneuron, which synapses with a motor neuron that contracts the arm muscles. Simultaneously, a separate signal travels up the spinal cord to the brain, arriving approximately 0.2 seconds after the reflex is already initiated.

Describe the afferent pathway of the reflex arc, naming the structures the nerve impulse passes through from the finger to the spinal cord. [1]

Explain how the spinal cord circuit completes the reflex arc and produces a motor response. [2]

Using the 0.2-second delay as evidence, justify the conclusion that the reflex arc is faster than a conscious response. [2]

Solutions

42QuestionReflex Arcs and Response to StimuliAssessment Practice

3 marks~5 minCriterion B

The bar graph below shows the average reaction times and synapse counts for three spinal/cranial reflex arcs.

Patellar reflex	1 synapse	50 ms
Withdrawal reflex	3 synapses	150 ms
Pupillary light reflex	2 synapses	200 ms

State the relationship between synapse number and reaction time shown by the patellar and withdrawal reflexes. [1]

Explain how synaptic delay accounts for the difference in reaction time between the patellar reflex and the withdrawal reflex. [1]

The pupillary light reflex has fewer synapses than the withdrawal reflex yet a longer reaction time. Analyse what this reveals about the factors that determine reaction time in a reflex arc. [1]

Solutions

43QuestionCommon disordersAssessment Practice

2 marks~3 minCriterion D

A 35-year-old woman with a family history of Huntington's disease — a neurodegenerative disorder caused by a dominant allele — is currently symptom-free and considering predictive genetic testing.

Identify and explain one ethical issue she may face when deciding whether to undergo this testing. [2]

Solutions

44QuestionCentral and Peripheral Nervous SystemAssessment Practice

4 marks~6 minCriterion D

A 30-year-old patient with a complete spinal cord injury at C5 is offered an experimental brain-computer interface (BCI). Electrodes implanted in the motor cortex interpret neural signals to control a robotic arm, restoring basic hand movements. Clinical trials report a 15% infection risk at the implant site. Signal quality degrades noticeably within 6 months, requiring surgical electrode replacement to restore function. The device also requires daily recalibration by the patient at home.

Discuss the ethical tension between respecting the patient's autonomy and protecting them from the harms associated with this BCI. [2]

Discuss how signal degradation over time affects the real-world viability of this BCI as a long-term treatment for patients with spinal cord injury. [2]

Solutions

45QuestionCommon disordersAssessment Practice

3 marks~5 minCriterion A

The diagram shows a myelinated neuron with structure X labelled on the axon.

Identify structure X. [1]

Explain how structure X increases the speed of nerve impulse transmission along the axon. [1]

A patient with multiple sclerosis (MS) shows progressive damage to structure X. Evaluate how this damage accounts for the slowing of nerve impulse transmission seen in MS patients. [1]

Solutions

46QuestionCommon disordersAssessment Practice

5 marks~8 minCriterion C

A 68-year-old patient with Alzheimer's disease shows reduced acetylcholine levels in the hippocampus and extracellular amyloid plaque deposits between neurons. Postsynaptic neurons in affected regions show decreased acetylcholine receptor density.

Two hypotheses explain the observed memory loss:
- Hypothesis 1: amyloid plaques disrupt neurotransmitter release from presynaptic terminals.
- Hypothesis 2: degradation of receptors on postsynaptic neurons impairs signal reception.

Describe the sequence of events in normal cholinergic synaptic transmission, from action potential arrival to postsynaptic response. [2]

Explain how each piece of evidence either supports or weakens each hypothesis. [2]

Justify which hypothesis is more strongly supported by the evidence provided. [1]

Solutions

47QuestionComparing Nervous and Hormonal ControlAssessment Practice

3 marks~5 minCriterion C

The diagrams show two responses to stimuli.

Diagram A: A hand touches a hot stove. A pathway runs from the hand → spinal cord (sensory neuron) → arm muscle (motor neuron), causing the hand to pull away.

Diagram B: A person perceives danger. A pathway runs from the brain → adrenal gland (via nervous system), which releases adrenaline into the bloodstream → heart, increasing heart rate.

Identify the type of control system (nervous or hormonal) illustrated in each diagram. [1]

Explain why the response in Diagram A occurs more rapidly than the response in Diagram B. [1]

A student claims that the hormonal response in Diagram B is less useful than the nervous response in Diagram A because it is slower. Evaluate this claim. [1]

Solutions

48QuestionCommon diseasesAssessment Practice

6 marks~9 minCriterion B

The table below summarises four respiratory diseases.

Disease — Onset — Primary symptom — Spirometry pattern

Asthma — Intermittent/acute — Wheeze — Obstructive (reversible)
COPD — Gradual/chronic — Productive cough with sputum — Obstructive (irreversible)
Pneumonia — Acute — Productive cough with fever — Restrictive
Pulmonary fibrosis — Gradual/chronic — Dry cough — Restrictive (irreversible)

Bronchiectasis is characterised by permanent dilation of the bronchi caused by chronic inflammation and recurrent infections, leading to irreversible structural damage of the airway walls and mucus hypersecretion.

Identify the relationship between disease onset and spirometry pattern shown in the table. [1]

Deduce the likely symptom progression and spirometry pattern for a patient with bronchiectasis, using evidence from the table to support your reasoning. [2]

Discuss how the biological mechanisms of airway wall damage and mucus hypersecretion in bronchiectasis produce its characteristic spirometry pattern, distinguishing it from the mechanisms responsible for the spirometry patterns seen in asthma and pulmonary fibrosis. [3]

Solutions

49QuestionMain organsAssessment Practice

3 marks~5 minCriterion C

The diagram shows a cross-section of the human respiratory system, labelling the trachea, bronchi, bronchioles, and alveoli.

State one structural feature of the alveoli that increases the rate of gas exchange. [1]

Explain how a rich capillary network surrounding the alveoli maintains efficient gas exchange. [1]

A student claims that increasing alveolar wall thickness would have no effect on the rate of oxygen diffusion into the blood. Evaluate this claim. [1]

Solutions

50QuestionCommon diseasesAssessment Practice

6 marks~9 minCriterion D

A government is considering a nationwide ban on tobacco sales to reduce respiratory disease. Studies project that over 20 years, smoking prevalence could fall by 40%, and tobacco farmland currently covers 15% of the country's agricultural area.

Identify two specific ways tobacco smoke damages the respiratory system, naming the disease each causes. [2]

Explain how a 40% reduction in smoking prevalence would affect rates of respiratory disease and secondhand smoke exposure across the population over 20 years. [2]

Evaluate the overall effectiveness of this ban, considering both its benefits — including environmental impacts of reduced tobacco farming — and its limitations, such as black market activity and economic displacement of farming communities. [2]

Solutions

51QuestionCommon diseasesAssessment Practice

4 marks~6 minCriterion A

The diagrams below show cross-sections of a bronchiole from a healthy individual (A) and from a patient with chronic obstructive pulmonary disease (COPD) (B).

Diagram A – Healthy bronchiole: thin, smooth airway wall; wide, open lumen; intact alveoli of normal size.

Diagram B – COPD bronchiole: thickened, inflamed airway wall with excess mucus; narrowed, partially blocked lumen; damaged, enlarged alveoli with reduced surface area.

Identify two structural differences between bronchiole A and bronchiole B visible in the diagrams. [2]

Explain how the structural changes shown in diagram B contribute to shortness of breath in a COPD patient. [2]

Solutions

52QuestionCommon diseasesAssessment Practice

3 marks~5 minCriterion C

The graph below shows the prevalence of three respiratory diseases — asthma, COPD, and lung cancer — in a population from 2010 to 2020.

Asthma prevalence remains stable at approximately 80–85 cases per 1000. COPD prevalence increases from 30 (2010) to 40 (2015) to 50 (2020) cases per 1000. Lung cancer prevalence increases from 10 (2010) to 15 (2015) to 20 (2020) cases per 1000.

State the change in COPD prevalence between 2010 and 2020. [1]

Explain one biological reason why COPD prevalence increases over time in an ageing population. [1]

Analyse why asthma prevalence remaining stable does not mean asthma poses a lesser public health concern than COPD. [1]

Solutions

53QuestionCommon diseasesAssessment Practice

6 marks~9 minCriterion D

A school district is considering a policy requiring all students to receive the influenza vaccine before attending school. Influenza spreads primarily via respiratory droplets; vaccination stimulates antibody production, reducing transmission. Supporters cite herd immunity as protection for immunocompromised students who cannot be vaccinated. Opponents, including some parents, argue the policy violates religious freedom and parental autonomy over medical decisions. Equity concerns also exist, as vaccine access varies across the community.

Explain how vaccination interrupts influenza transmission and contributes to herd immunity in a school population. [2]

Analyse the public health benefits of mandatory vaccination against the ethical challenges it raises in a diverse community. [4]

Solutions

54QuestionCommon problemsAssessment Practice

5 marks~8 minCriterion B

An athlete's grip endurance is measured as the time (in seconds) until fatigue during a sustained handgrip contraction. Five athletes were tested before and immediately after a 60-second sprint.

Athlete	A	B	C	D	E
Before sprint (s)	45	52	38	60	47
After sprint (s)	22	28	15	35	25

Calculate the decrease in grip endurance time for each athlete. Analyse the data to identify the pattern and explain, with reference to a named physiological mechanism, why sprinting reduces muscle endurance. [2]

Propose an experiment to investigate whether a 30-second rest interval between the sprint and the grip test produces less muscle fatigue than a 60-second rest interval. Your proposal must include: the independent and dependent variables; at least two control variables; a step-by-step procedure; and one method each to ensure reliability and validity. [3]

Solutions

55QuestionCommon problemsAssessment Practice

6 marks~9 minCriterion C

During a high-intensity cycling test, blood lactate concentration (mmol/L) was recorded for three athletes:

Time — Untrained — Moderately Trained — Elite

Rest: 1.0	0.8	0.6
After 1 min: 3.5	2.8	1.9
After 5 min: 8.2	5.1	3.0
After 10 min: 10.5	4.0	1.2

Describe the pattern of blood lactate accumulation for the untrained athlete over the 10-minute exercise period, using data from the table. [2]

Identify which athlete demonstrates the fastest lactate clearance after the 5-minute peak and explain how training level correlates with this ability. [2]

Analyse how the muscular system responds to sustained high-intensity exercise to produce lactate, and evaluate why lactate accumulation is greater in untrained athletes. [2]

Solutions

56QuestionCommon problemsAssessment Practice

4 marks~6 minCriterion A

During a 400 m sprint, muscles rapidly deplete available oxygen, forcing a switch in metabolic pathway. The diagram shows elevated lactic acid concentrations in the sprinter's leg muscles immediately after the race.

Describe the cellular process that causes lactic acid to accumulate in muscle tissue during intense exercise. [2]

Explain why the sprinter continues to breathe heavily for several minutes after crossing the finish line, referring to the concept of oxygen debt in your answer. [2]

Solutions

57QuestionCommon problemsAssessment Practice

5 marks~8 minCriterion C

During intense exercise, muscles produce lactate as a by-product of anaerobic respiration. A study investigated whether lactic acid buildup directly causes muscle fatigue.

Three groups of ten athletes each were assessed:
Sprint group: 30-second sprint intervals
Jog group: steady-state jogging at 60% maximum heart rate
Control group: rested

Blood lactate (mmol/L) measured immediately after:

Sprint	12.1	14.5	11.8	13.2	15.0	10.9	16.2	12.7	13.9	14.1
Jog	2.3	2.1	2.5	2.0	2.4	2.2	2.6	2.3	2.1	2.4
Control	1.0	0.9	1.1	1.0	1.2	0.8	1.0	1.1	0.9	1.0

All athletes reported muscle fatigue after sprinting; none reported fatigue after jogging.

Calculate the mean blood lactate concentration for each group. [1]

Describe the trend in lactate concentration across the three groups and identify one anomaly in the sprint data, justifying your choice. [2]

Evaluate the hypothesis that lactic acid buildup directly causes muscle fatigue, using the data and identifying two limitations of the experimental design that affect this conclusion. [2]

Solutions

58QuestionCommon problemsAssessment Practice

6 marks~9 minCriterion D

A pharmaceutical company has developed a myostatin-inhibitor drug. Myostatin is a protein that normally limits muscle growth. Clinical trials show the drug effectively prevents muscle wasting in bedridden patients. However, healthy athletes have begun requesting the drug to enhance performance and muscle appearance. The company is now lobbying regulators to approve the drug for non-medical use.

State one ethical concern raised by prescribing this drug to healthy athletes for performance enhancement. [1]

Explain one potential health risk associated with long-term suppression of myostatin in the human body. [2]

Evaluate whether this drug should be restricted to medical use only, or also permitted for cosmetic and performance purposes. [3]

Solutions

59QuestionCommon problemsAssessment Practice

3 marks~5 minCriterion A

A sports physiotherapist records the average recovery time for three common muscle injuries:

Contusion: 2 weeks
Strain: 3 weeks
Tear: 8 weeks

State the injury with the shortest recovery time. [1]

Explain why a muscle strain heals more quickly than a muscle tear. [1]

A patient with a muscle tear is advised that recovery time may extend beyond 8 weeks if scar tissue forms incorrectly. Explain how abnormal scar tissue formation could impair muscle function during the remodelling phase. [1]

Solutions

60QuestionCommon problemsAssessment Practice

6 marks~9 minCriterion D

Powered exoskeletons are robotic suits that assist movement by compensating for weakened skeletal muscle. Sarcopenia — the progressive, age-related loss of muscle mass and strength — affects approximately 10–30% of adults over 60, increasing fall risk and dependence on care.

Explain how sarcopenia affects skeletal muscle at the cellular level, and describe one way a powered exoskeleton compensates for this loss. [2]

Analyse one environmental concern arising from the widespread adoption of powered exoskeletons in elderly care. [2]

Evaluate whether the societal benefits of large-scale exoskeleton use outweigh its environmental costs, proposing one evidence-based strategy to reduce those costs. [2]

Solutions

61QuestionCommon problemsAssessment Practice

4 marks~6 minCriterion A

The diagram below shows two bone fractures in a child's forearm: a greenstick fracture (Figure 1) and a complete fracture (Figure 2).

Identify the type of fracture shown in Figure 1. [1]

Explain the role of the periosteum during the healing of a greenstick fracture, including how a callus forms and how it restores bone integrity. [3]

Solutions

62QuestionFunctionsAssessment Practice

3 marks~5 minCriterion B

Four human bones are listed below with their primary functions and structural features.

Bone: Femur	Function: Body weight support	Feature: Hollow shaft
Bone: Skull	Function: Brain protection	Feature: Fused plates
Bone: Rib	Function: Organ protection	Feature: Curved shape
Bone: Patella	Function: Joint articulation	Feature: Small, rounded shape

State one structural feature from the table and identify its corresponding function. [1]

Explain how the structural feature of the femur suits its function of body weight support. [1]

Analyse the trend connecting structural features to functions across all four bones, identifying what distinguishes bones that provide support or protection from bones that enable movement. [1]

Solutions

63QuestionFunctionsAssessment Practice

6 marks~9 minCriterion C

The table below shows osteoblast activity (bone formation) and osteoclast activity (bone resorption) alongside bone density for five individuals.

Age (years)	12	25	40	60	80
Osteoblast activity (%)	85	70	55	40	30
Osteoclast activity (%)	20	30	45	60	70
Bone density (g/cm²)	1.2	1.1	1.0	0.85	0.7

Analyse the trend in the balance between osteoblast and osteoclast activity as age increases. [2]

Using the data, calculate the average rate of bone density decline between ages 60 and 80, then deduce the expected bone density for a 70-year-old. [2]

Evaluate whether the shift in cellular activity balance is sufficient on its own to explain the decline in bone density, or whether additional biological factors must be considered. [2]

Solutions

64QuestionCommon problemsAssessment Practice

5 marks~8 minCriterion D

A controlled study investigated whether vitamin D deficiency delays bone fracture healing. Twenty rats with induced fractures were divided equally into two groups. Group A received a vitamin D-deficient diet; Group B received a normal diet. After four weeks, X-ray imaging measured callus formation area (

\text{mm}^2

) at each fracture site.

Group A (vitamin D deficient): 12, 15, 10, 8, 14, 11, 9, 13, 10, 12

Group B (normal diet): 22, 25, 20, 28, 24, 26, 23, 27, 21, 25

Identify the independent variable and the dependent variable in this experiment. [1]

Calculate the mean callus formation area for each group and describe the trend shown by the data. [2]

Evaluate whether the data support the hypothesis that vitamin D deficiency delays bone fracture healing. In your answer, include the role of vitamin D in bone repair and at least one limitation of this study. [2]

Solutions

65QuestionCommon problemsAssessment Practice

3 marks~5 minCriterion A

The diagram below shows a simple (closed) fracture and a compound (open) fracture of the femur.

State one structural difference between a simple fracture and a compound fracture. [1]

Explain the role of the periosteum in bone healing following a fracture. [1]

Analyse why a compound fracture is more likely to result in delayed healing than a simple fracture of the same bone. [1]

Solutions

66QuestionFunctionsAssessment Practice

5 marks~8 minCriterion C

Two groups of rats were studied over 8 weeks. Group A received a calcium-deficient diet; Group B received a normal diet. Bone density and blood calcium were measured at week 0 and week 8.

Bone density (

\text{g/cm}^3

): Group A: week 0 = 1.20, week 8 = 0.85 | Group B: week 0 = 1.20, week 8 = 1.20

Blood calcium (

\text{mg/dL}

): Group A: week 0 = 10.0, week 8 = 9.8 | Group B: week 0 = 10.0, week 8 = 10.0

Calculate the percentage decrease in bone density for Group A between week 0 and week 8. [1]

Explain how the roles of osteoclasts and parathyroid hormone (PTH) account for the changes observed in Group A. [2]

Evaluate whether the experimental data support the hypothesis: "The skeletal system prioritises maintaining blood calcium levels over preserving bone structural integrity." In your answer, discuss one limitation of the experimental design. [2]

Solutions

67QuestionChemical signalingAssessment Practice

4 marks~6 minCriterion A

The graph below shows blood glucose concentration measured at intervals following a carbohydrate-rich meal.

Time (min)	0	30	60	90	120
Blood glucose (mg/dL)	90	140	110	85	90

Describe the sequence of hormonal events that occurs between 0 and 60 minutes, using the terms: insulin, receptor binding, and target cells. [2]

Explain how the data between 60 and 120 minutes demonstrates that negative feedback is self-limiting once blood glucose approaches its set point. [2]

Solutions

68QuestionChemical signalingAssessment Practice

8 marks~12 minCriterion C

A study investigated how insulin dose affects blood glucose regulation. Five healthy adults each received a low, medium, or high insulin dose on separate days. Blood glucose (mmol/L) was measured at five time points after injection. Average results are shown below.

Time (min)	0	30	60	90	120
Low dose (mmol/L)	5.5	5.0	4.8	4.7	4.6
Medium dose (mmol/L)	5.5	4.5	3.8	3.5	3.4
High dose (mmol/L)	5.5	4.0	3.2	2.8	2.7

Describe the relationship between insulin dose and both the rate and the final level of blood glucose decrease shown in the data. [3]

Deduce the average blood glucose level for the medium dose group at 150 minutes, using evidence from the data to support your reasoning. [2]

Analyse how the principles of negative feedback and insulin-receptor saturation together explain the pattern of diminishing glucose decrease observed across all three doses. [3]

Solutions

69QuestionChemical 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

5 \, \text{mmol/L}

and insulin is low. Glucose peaks at approximately

8 \, \text{mmol/L}

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.

Describe the trends in blood glucose and insulin concentration between 0 and 180 minutes, referring to specific values from the graph. [1]

Explain how the endocrine system uses chemical signalling to return blood glucose to its baseline concentration after the meal. [1]

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

70QuestionChemical 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.

State what structural feature a cell must possess in order to respond to a hormone. [1]

Explain why the liver cell responds to adrenaline while the muscle cell does not. [2]

Analyse what would happen to blood glucose regulation if muscle cells also expressed adrenaline receptors. Justify your reasoning. [1]

Solutions

71QuestionChemical 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

Explain the role of cortisol in the hypothalamic-pituitary-adrenal (HPA) axis negative feedback loop. [1]

Analyse how the data from the adrenalectomy groups supports the conclusion that cortisol maintains blood glucose levels. [2]

Evaluate whether this experiment tests negative feedback regulation of cortisol, identifying two limitations of the experimental design. [2]

Solutions

72QuestionWorkingAssessment 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.

Explain two clinical benefits and one clinical risk of this HRT for menopausal women. [2]

Analyse how hormone metabolites entering wastewater systems affect aquatic organisms and their populations. [2]

Evaluate the long-term societal and environmental impact of this HRT, considering limitations of the clinical trial data. [2]

Solutions