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Health and Diseases

Health and Diseases — Free MYP5 Biology Practice Questions

1QuestionModes of Transmission of PathogensConcept Practice

4 marks~6 minCriterion D

A sewage leak contaminates the drinking water supply of a rural village. The diagram shows the faecal-oral transmission route of a bacterial pathogen, including vehicles such as water, food, hands, and soil connecting a faecal source to a new host.

Identify two vehicles through which faecal-oral transmission of a bacterial pathogen can occur. [2]

Explain how water treatment interrupts the faecal-oral transmission route. [1]

Analyse why faecal-oral diseases are more prevalent in low-income countries than in high-income countries. [1]

Solutions

2QuestionClassification of PathogensConcept Practice

3 marks~5 minCriterion A

A hospital records the following bacterial infections over one year:

Gram-positive bacteria: 120 infections
Gram-negative bacteria: 85 infections

Despite causing fewer infections, Gram-negative bacteria are considered a greater clinical threat due to their antibiotic resistance.

State which bacterial group caused more infections and calculate how many more infections it caused compared to the other group. [1]

Explain why Gram-negative bacteria are more resistant to antibiotics than Gram-positive bacteria, referring to their cell wall structure. [1]

Evaluate why a hospital might prioritise controlling Gram-negative infections over Gram-positive infections, even though Gram-negative bacteria caused fewer cases. [1]

Solutions

3QuestionImportance of VaccinationConcept Practice

2 marks~3 minCriterion A

During an immune response, a pathogen enters a lymph node and is detected by several immune cells. The diagram below shows a section of a lymph node with four labelled immune cells: B cell, T cell, macrophage, and dendritic cell.

Identify the immune cell in the diagram that is responsible for producing antibodies. [1]

Explain how this cell carries out its antibody-producing function during an immune response. [1]

Solutions

4QuestionImpact of Diet on HealthConcept Practice

2 marks~3 minCriterion A

The diagram below shows a villus from the small intestine, with structures labeled X visible on the surface of the epithelial cells.

Identify the structures labeled X. [1]

Explain how these structures increase the efficiency of nutrient absorption in the small intestine. [1]

Solutions

5QuestionCauses of Lifestyle DiseasesConcept Practice

2 marks~3 minCriterion A

The electron micrograph below shows a liver cell from a person with chronic excessive alcohol consumption. Organelle X appears swollen, with disrupted inner membrane folds.

Identify organelle X. [1]

Explain how damage to organelle X impairs ATP production during aerobic respiration. [1]

Solutions

6QuestionCommunicable DiseasesConcept Practice

2 marks~3 minCriterion A

The diagram shows two pathogens. Pathogen A contains a protein coat and genetic material only. Pathogen B contains a cell wall, cell membrane, cytoplasm, and genetic material.

Identify which pathogen is not cellular and state the term used to classify this type of pathogen. [1]

State one communicable disease caused by this type of pathogen. [1]

Solutions

7QuestionPathogens: Bacteria, Viruses, Fungi, and ParasitesAssessment Practice

4 marks~6 minCriterion C

The diagram shows four pathogens and their transmission routes: influenza virus (respiratory droplets), norovirus (contaminated food/water), MRSA (direct skin contact), and malaria parasite (mosquito vector).

State the difference between direct and indirect transmission of a pathogen. [1]

Describe how influenza virus is transmitted from an infected person to an uninfected person. [1]

Evaluate the effectiveness of handwashing as a public health measure by analysing which transmission routes shown in the diagram it would interrupt and which it would not. [2]

Solutions

8QuestionModes of Transmission of PathogensAssessment Practice

6 marks~9 minCriterion B

During a disease outbreak, the number of new infection cases per 100,000 people was recorded over 30 days in two communities across four transmission modes.

Airborne droplet — Urban	450	Rural: 120
Contaminated water — Urban	80	Rural: 310
Direct contact — Urban	200	Rural: 90
Vector-borne — Urban	60	Rural: 180

Identify the dominant transmission mode in the Urban community and the dominant transmission mode in the Rural community. [2]

Describe the pattern in how transmission mode effectiveness differs between the Urban and Rural communities, using data from the table. [2]

Analyse how environmental factors such as population density and sanitation infrastructure determine which transmission mode dominates in a given community. Use specific evidence from the data to support your analysis. [2]

Solutions

9QuestionClassification of PathogensAssessment Practice

2 marks~3 minCriterion D

During a respiratory illness outbreak, a clinic must decide whether to prescribe antibiotics. Rapid diagnostic tests can classify the causative pathogen as either bacterial or viral.

Explain how classifying a pathogen as bacterial rather than viral directly influences the treatment a clinician prescribes. [1]

Discuss one ethical issue that arises when clinics in low-income settings lack access to rapid diagnostic tests for pathogen classification. [1]

Solutions

10QuestionClassification of PathogensAssessment Practice

5 marks~8 minCriterion A

The electron micrograph below shows two pathogens imaged at the same scale: a bacteriophage (a type of virus) and Mycobacterium tuberculosis (a bacterium).

Identify which structure in the micrograph is the bacteriophage and which is Mycobacterium tuberculosis. [1]

Describe three observable structural differences between the two pathogens visible in the micrograph, using correct biological terminology. [3]

Justify how the structural features of each pathogen relate to its mode of reproduction and infection. [1]

Solutions

11QuestionPathogen-Host InteractionsAssessment Practice

8 marks~12 minCriterion C

A researcher infects two groups of mice with either a wild-type bacterial strain (WT) or a flagellin-gene deletion mutant (

\Delta fliC

). Bacterial load (CFU/mL) and antibody titre (relative units) are recorded over 14 days.

Day	2	4	6	8	10	12	14
WT bacterial load	$1.2 \times 10^{6}$	$2.5 \times 10^{6}$	$1.8 \times 10^{6}$	$5.0 \times 10^{5}$	$1.0 \times 10^{5}$	$5.0 \times 10^{3}$	0
WT antibody titre	0	50	300	1200	2500	3000	3200
$\Delta fliC$ bacterial load	$1.5 \times 10^{6}$	$3.0 \times 10^{6}$	$4.0 \times 10^{6}$	$3.5 \times 10^{6}$	$2.0 \times 10^{6}$	$1.0 \times 10^{6}$	$5.0 \times 10^{5}$
$\Delta fliC$ antibody titre	0	10	40	100	200	250	300

Describe the relationship between bacterial load and antibody titre for the WT strain. [2]

Explain why the

\Delta fliC

strain produces a weaker antibody response than the WT strain, referring to PAMP recognition. [3]

Evaluate which strain is more virulent, using both the data and your understanding of flagellin's role in activating adaptive immunity. [3]

Solutions

12QuestionClassification of PathogensAssessment Practice

5 marks~8 minCriterion C

A researcher applies Koch's postulates to investigate four bacterial strains (W, X, Y, Z) isolated from diseased mice. The results are shown below.

Postulate — W — X — Y — Z
1. Present in all diseased individuals: Yes — Yes — Yes — Yes
2. Isolated and grown in pure culture: Yes — Yes — No — Yes
3. Inoculation causes disease in healthy mice: Yes — No — Yes — Yes
4. Re-isolated from experimentally infected mice: Yes — Yes — Yes — No

State the purpose of Koch's postulates in microbiology. [1]

Identify which strain satisfies all four postulates and explain why each postulate is necessary to establish a bacterium as the causative agent of a disease. [2]

Evaluate the data for strains X, Y, and Z, justifying why each cannot be confirmed as the causative pathogen. [2]

Solutions

13QuestionHerd Immunity and Disease PreventionAssessment Practice

3 marks~5 minCriterion C

The table below shows vaccination coverage and confirmed measles cases across five communities over one year.

Community	A	B	C	D	E
Vaccination coverage (%)	95	90	80	70	60
Measles cases	5	20	50	80	120

Deduce the relationship between vaccination coverage and the number of measles cases, using data from the table. [1]

Predict the likely number of measles cases in a community with 50% vaccination coverage. [1]

Evaluate whether vaccination coverage alone is sufficient to explain differences in measles cases between communities. [1]

Solutions

14QuestionHerd Immunity and Disease PreventionAssessment Practice

2 marks~3 minCriterion A

Three populations have the following vaccination coverage: Population A: 60%, Population B: 80%, Population C: 95%. A pathogen is introduced into each population simultaneously. Unvaccinated individuals remain fully susceptible to infection.

Describe how the spread of the pathogen differs across Populations A, B, and C, using correct biological terminology. [1]

Explain why Population C achieves herd immunity, while Populations A and B do not. [1]

Solutions

15QuestionHerd Immunity and Disease PreventionAssessment Practice

3 marks~5 minCriterion A

The graph below shows the number of new measles infections over time in a constant-sized population, at vaccination coverages of 50%, 75%, 90%, and 95%.

State the relationship between the percentage of vaccinated individuals and the number of new infections shown in the graph. [1]

Explain how increasing vaccination coverage reduces the transmission of measles through a population. [1]

Identify the vaccination coverage at which herd immunity is achieved for measles and justify why this threshold is higher than for most other infectious diseases. [1]

Solutions

16QuestionImportance of VaccinationAssessment Practice

3 marks~5 minCriterion B

The graph below shows vaccination coverage (percent) and disease incidence (cases per 100,000 people) recorded annually over ten years for a single disease.

Year	1	2	3	4	5	6	7	8	9	10
Vaccination coverage (percent)	40	45	50	55	60	65	70	75	80	85
Disease cases per 100,000	200	180	150	120	90	60	35	20	10	5

Identify the relationship between vaccination coverage and disease incidence shown in the graph, using data to support your answer. [1]

Explain how increasing the proportion of vaccinated individuals in a population reduces disease incidence. [1]

Discuss how the pattern of decline in disease cases supports the concept of herd immunity, with reference to a threshold effect visible in the data. [1]

Solutions

17QuestionHerd Immunity and Disease PreventionAssessment Practice

3 marks~5 minCriterion A

Three populations (A, B, C) are each exposed to the same infectious pathogen. The proportion of vaccinated individuals in each population is shown below.

Population A: 60% vaccinated
Population B: 80% vaccinated
Population C: 95% vaccinated

The critical vaccination threshold for this pathogen is known to exceed 80%.

Identify which population is most likely to achieve herd immunity and explain how the concept of the critical vaccination threshold supports your answer. [2]

The basic reproduction number (

R_0

) of a pathogen is related to the critical vaccination threshold (

p_c

) by:

p_c = 1 - \frac{1}{R_0}

Use this relationship to explain why a more transmissible pathogen requires a higher proportion of vaccinated individuals to achieve herd immunity. [1]

Solutions

18QuestionHerd Immunity and Disease PreventionAssessment Practice

6 marks~9 minCriterion D

A school board is considering mandating the MMR vaccine for all students to achieve herd immunity against measles. Measles has a basic reproduction number (

R_0

) of 15. The herd immunity threshold is given by:

v = 1 - \frac{1}{R_0}

where

v

is the minimum proportion of the population that must be immune.

Calculate the minimum vaccination rate, as a percentage, needed to achieve herd immunity. [2]

A proposed religious exemption policy would reduce the vaccination rate to 88%. Explain how this reduction affects herd immunity and the risk to immunocompromised students who cannot receive the MMR vaccine. [2]

Evaluate whether the school board should adopt the religious exemption policy, considering the tension between individual rights and community health, and one limitation of using

R_0

to model real-world disease spread. [2]

Solutions

19QuestionHerd Immunity and Disease PreventionAssessment Practice

2 marks~3 minCriterion D

A student refuses the measles vaccine, arguing that vaccinated classmates will protect them through herd immunity. Measles requires approximately 95% vaccination coverage in a population to maintain herd immunity.

Refer to the image showing two populations: one with high vaccination coverage and one with low vaccination coverage.

Identify the ethical issue raised by the student's reasoning. [1]

Explain why this reasoning becomes self-defeating if a significant number of students adopt the same approach. [1]

Solutions

20QuestionCommunicable DiseasesAssessment Practice

4 marks~6 minCriterion C

The diagram below shows two individuals. Person A has Type 2 diabetes, caused by poor diet and physical inactivity, leading to insulin resistance. Person B has influenza, caused by the influenza virus — a pathogen transmitted through respiratory droplets.

Explain why Type 2 diabetes is classified as a lifestyle disease and influenza is classified as a communicable disease. Refer to the causes shown in the diagram. [2]

Deduce whether each disease can spread from Person A or Person B to another individual. Support your deduction with a reason for each disease. [1]

A public health team wants to reduce the spread of influenza in a school. Evaluate one strategy they could use, considering both its effectiveness and a limitation. [1]

Solutions

21QuestionCauses of Lifestyle DiseasesAssessment Practice

7 marks~11 minCriterion B

A study tracked 20 adults over five years, recording BMI, weekly physical activity (hours), and fasting blood glucose (mmol/L) at the start and end. The table below shows the five-year change in blood glucose for four representative individuals.

Individual A	BMI 22	activity 7 h/week	glucose change $+0.1$ mmol/L
Individual B	BMI 28	activity 3 h/week	glucose change $+1.2$ mmol/L
Individual C	BMI 32	activity 1 h/week	glucose change $+2.5$ mmol/L
Individual D	BMI 35	activity 0 h/week	glucose change $+4.0$ mmol/L

Interpret the pattern relating BMI, physical activity, and blood glucose change. State a general rule that predicts the risk of progressing from prediabetes to Type 2 diabetes based on these two factors. [2]

Deduce the expected five-year blood glucose change for an individual with BMI 30 and 2 h/week of physical activity. Show your reasoning. [2]

Justify why high BMI and low physical activity each contribute to rising blood glucose, and explain why their combined effect is greater than either factor alone. [3]

Solutions

22QuestionNon-Communicable Diseases OverviewAssessment Practice

4 marks~6 minCriterion A

The diagram below shows a cross-section of a healthy artery alongside an artery affected by atherosclerosis.

Identify two components that accumulate within the artery wall during the development of atherosclerosis. [1]

Explain how the accumulation of these components narrows the lumen and reduces blood flow to downstream tissues. [2]

Analyse how a narrowed arterial lumen leads to an increase in blood pressure, referring to both resistance and cardiac response. [1]

Solutions

23QuestionCommunicable DiseasesAssessment Practice

6 marks~9 minCriterion D

A government must choose between two public health interventions: (1) a nationwide tax on sugary drinks to reduce obesity, and (2) increased funding for measles vaccination programmes. Measles has a basic reproduction number (

R_0

) of approximately 12–18. Obesity-driven type 2 diabetes progresses over decades through chronic hyperglycaemia and insulin resistance, whereas measles has an incubation period of approximately 10–12 days.

Explain one positive and one negative societal impact of the sugar tax, using biological reasoning in each case. [2]

Analyse the societal and environmental impacts of prioritising the sugar tax over the vaccination programme. In your answer, refer to herd immunity, disease transmission, and plastic or medical waste. [2]

Evaluate the limitations of using a single cost-benefit model to compare these two interventions. In your answer, refer to biological time scales, ethical considerations, and methodological constraints. [2]

Solutions

24QuestionCauses of Lifestyle DiseasesAssessment Practice

2 marks~3 minCriterion D

A government health agency proposes banning sugary drink advertising near schools to reduce type 2 diabetes rates. Beverage companies argue this infringes their right to advertise legal products.

Outline the ethical conflict between the public health goal and the commercial rights of beverage companies. [1]

Explain one limitation of using advertising bans alone to reduce type 2 diabetes rates, referring to either a biological or a social factor. [1]

Solutions