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Systems in Organisms — Free MYP3 Sciences Practice Questions
1QuestionTypes of Joints and Their MovementConcept Practice
2 marks~3 minCriterion B
A student investigates how the angle of the elbow joint affects the distance a ball is thrown. The same person throws the same ball at elbow angles of , , and , measuring the throwing distance each time.
a
Identify the independent variable and the dependent variable in this investigation. [1]
b
State one controlled variable and explain why keeping it constant makes the investigation a fair test. [1]
Solutions
2QuestionFunctions of the Human SkeletonConcept Practice
2 marks~3 minCriterion A
The diagram below shows the human skeleton with one bone labelled X.
a
Identify the bone labelled X. [1]
b
Explain why the shape and hardness of bone X makes it well suited to its primary function. [1]
Solutions
3QuestionBasic Stages of Human ReproductionConcept Practice
3 marks~5 minCriterion B
The table below shows the number of cells in a developing human embryo at various days after fertilization.
| Day (days after fertilization) | 1 | 2 | 3 | 4 |
|---|---|---|---|---|
| Number of cells | 1 | 2 | 4 | 8 |
a
Describe the trend in the number of cells shown in the table. [1]
b
Identify the biological process responsible for this trend. [1]
c
A student claims that by Day 5 the embryo will contain 16 cells. Using the data in the table, explain whether this claim is likely to be correct. [1]
Solutions
4QuestionBasic Stages of Human ReproductionConcept Practice
2 marks~3 minCriterion A
The diagram below shows the female reproductive system with four labeled structures: A (ovary), B (fallopian tube), C (uterus), and D (vagina).
a
Identify the letter that represents the structure where an egg is released during ovulation. [1]
b
Explain what happens to the egg immediately after it is released from that structure. [1]
Solutions
5QuestionConcept of Excretion and Examples in HumansConcept Practice
2 marks~3 minCriterion A
The diagram shows a simplified outline of the human body with three excretory organs labeled A, B, and C.
a
Identify the letter that corresponds to the organ responsible for removing carbon dioxide () from the blood. [1]
b
Explain why removing from the blood is considered excretion rather than simply breathing. [1]
Solutions
6QuestionCase Studies of System Interactions in Daily LifeConcept Practice
3 marks~5 minCriterion A
The diagram shows nutrients moving from the small intestine into blood vessels after a meal.
a
Identify the process by which nutrients pass from the small intestine into the bloodstream. [1]
b
Explain how the digestive system and the circulatory system work together to deliver nutrients to body cells. In your answer, use the terms absorption and transport. [2]
Solutions
7QuestionAbsorption of Nutrients in the Small IntestineConcept Practice
2 marks~3 minCriterion A
The diagram shows a villus from the small intestine. Structure X is found on the surface of the epithelial cells lining the villus.
a
Identify structure X. [1]
b
Describe how structure X increases the efficiency of nutrient absorption. [1]
Solutions
8QuestionAbsorption of Nutrients in the Small IntestineConcept Practice
3 marks~5 minCriterion B
The table below shows data for three sections of the small intestine.
| Section | Villi per | Surface area () |
|---|---|---|
| Duodenum | 15 | 30 |
| Jejunum | 25 | 60 |
| Ileum | 40 | 90 |
a
State what happens to the surface area of the small intestine as the number of villi per increases. [1]
b
Explain how villi increase the surface area of the small intestine. [1]
c
Analyse how the data suggest that the ileum is the most efficient section for nutrient absorption. [1]
Solutions
9QuestionBlood Vessels Arteries Veins CapillariesConcept Practice
2 marks~3 minCriterion A
The diagram shows a cross-section of two blood vessels, labelled X and Y.
a
Identify which vessel is an artery. [1]
b
Describe one visible structural difference between vessel X and vessel Y shown in the cross-section. [1]
Solutions
10QuestionFunctions of the Human SkeletonAssessment Practice
6 marks~9 minCriterion D
Osteoporosis is a condition in which bone density decreases, making bones more fragile. Two elderly individuals, each with a mass of 70 kg, fall and experience a deceleration of upon impact.
Individual A (healthy): bone density
Individual B (osteoporosis): bone density
Individual A (healthy): bone density
Individual B (osteoporosis): bone density
a
Identify one function of the human skeleton related to protecting internal organs. [1]
b
Calculate the impact force experienced by each individual, using . [2]
c
The two individuals experience the same impact force, yet Individual B is at much greater risk of a hip fracture. Analyse two reasons why impact force alone is insufficient to predict fracture risk. [3]
Solutions
11QuestionFunctions of the Human SkeletonAssessment Practice
4 marks~6 minCriterion C
During a fall, a person lands hard on their chest. The diagram shows the rib cage surrounding the heart and lungs at the moment of impact.
a
Identify two organs protected by the rib cage. [1]
b
Explain how the structure of the rib cage protects these organs when the chest hits the ground. [2]
c
A classmate claims that flat bones would protect the heart and lungs just as well as curved ribs. Using your knowledge of the skeletal system, explain whether you agree with this claim. [1]
Solutions
12QuestionImportance of Reproduction for Species ContinuityAssessment Practice
4 marks~6 minCriterion D
The diagram shows a flower with three labeled parts: stigma, anther, and ovary.
a
State the role of the anther in reproduction. [1]
b
Explain how the positions of the anther and stigma work together to allow pollination to occur. [2]
c
A plant species exists in two populations: one that relies only on self-pollination and one that relies only on cross-pollination. Analyse which population is more likely to survive a sudden change in environmental conditions, and justify your reasoning. [1]
Solutions
13QuestionImportance of Reproduction for Species ContinuityAssessment Practice
5 marks~8 minCriterion C
A scientist studied two plant species in a forest affected by a fungal disease. Species A reproduces sexually, producing 50 seeds per plant per year with high genetic variation. Species B reproduces asexually, producing 200 identical offspring per plant per year.
Survivors recorded over three years:
Survivors recorded over three years:
| Species A | Year 1 = 1000 | Year 2 = 750 | Year 3 = 600 |
|---|---|---|---|
| Species B | Year 1 = 1000 | Year 2 = 400 | Year 3 = 100 |
a
Calculate the percentage survival rate of each species from Year 1 to Year 2. [2]
b
Explain why Species A shows greater resistance to the fungal disease than Species B, despite producing fewer offspring. [2]
c
Using the data and your understanding of genetic variation, evaluate the claim: "Asexual reproduction is always better for species continuity because it produces more offspring faster." [1]
Solutions
14QuestionRole of Kidneys and Urinary SystemAssessment Practice
4 marks~6 minCriterion B
A student investigates how fluid intake affects urine output. They drink different volumes of water and measure total urine produced over two hours.
| Water intake (mL) | 0 | 200 | 400 | 600 |
|---|---|---|---|---|
| Urine volume (mL) | 50 | 180 | 350 | 530 |
a
Describe the relationship between water intake and urine volume shown in the data. [1]
b
Explain why the body produces different volumes of urine at different levels of water intake. [1]
c
A second student drinks 800 mL of water. Use the data to predict their urine volume and justify your prediction. [2]
Solutions
15QuestionConcept of Excretion and Examples in HumansAssessment Practice
6 marks~9 minCriterion D
A patient with kidney failure undergoes dialysis. Blood passes through a machine containing a specialised filter that removes waste products such as urea, and the cleaned blood is returned to the body.
a
Describe the role of healthy kidneys in removing waste products from the blood. [1]
b
Explain how a dialysis machine performs the same function as healthy kidneys. [2]
c
A doctor tells the patient: "Dialysis keeps you alive, but it cannot fully replace what your kidneys do." Using your knowledge of kidney function, analyse this statement and decide whether you agree or disagree. Support your answer with one advantage and one disadvantage of dialysis compared to healthy kidneys. [3]
Solutions
16QuestionRole of Kidneys and Urinary SystemAssessment Practice
3 marks~5 minCriterion C
The graph shows kidney filtration rate (mL/min) plotted against blood pressure (mmHg), ranging from 60 mmHg to 180 mmHg.
a
Describe the relationship shown in the graph. [1]
b
Explain why the filtration rate remains constant above 80 mmHg. [1]
c
A patient's blood pressure rises from 80 mmHg to 160 mmHg during exercise. Using the graph and your knowledge of kidney autoregulation, explain whether this change is likely to damage the glomeruli. [1]
Solutions
17QuestionCase Studies of System Interactions in Daily LifeAssessment Practice
6 marks~9 minCriterion D
A student eats a large meal and immediately goes for a run. During the run, they feel nauseous and sluggish.
a
Describe how the digestive system and the muscular system compete for blood flow after a large meal. [2]
b
Explain why the "blood flow competition" model alone does not fully account for the body's response in this situation. [2]
c
A coach advises athletes to wait at least 90 minutes after a large meal before training. Using your understanding of system interactions, analyse whether this advice is well supported. [2]
Solutions
18QuestionHow Systems Work Together in the Human BodyAssessment Practice
6 marks~9 minCriterion C
After a meal, blood glucose concentration (mg/dL) and insulin secretion (arbitrary units) were recorded over 4 hours. At time 0, blood glucose is 90 mg/dL and insulin is 2 units. Blood glucose peaks at 140 mg/dL at 1 hour, then falls to 85 mg/dL at 4 hours. Insulin peaks at 18 units at 1.5 hours, then falls to 4 units at 4 hours.
a
State the peak blood glucose concentration and the time at which it occurs. [1]
b
Describe the relationship between blood glucose concentration and insulin secretion during the 4-hour period. [2]
c
Using evidence from the graph, explain how the digestive and circulatory systems work together to return blood glucose to its starting level after the meal. [3]
Solutions
19QuestionTransport of Nutrients and Oxygen to CellsAssessment Practice
6 marks~9 minCriterion B
A student investigates diffusion by placing a drop of blue dye at one end of a 10 cm gel block and recording how long the dye takes to reach the opposite end. Four concentration differences are tested.
| Concentration difference (%) | 5 | 10 | 15 | 20 |
|---|---|---|---|---|
| Time taken (min) | 40 | 20 | 13 | 10 |
a
Describe the relationship between concentration difference and time taken shown in the data. [1]
b
Calculate the predicted time taken for a concentration difference of 25%. Show your working. [2]
c
Explain why a larger concentration difference causes dye particles to reach the opposite end of the gel block more quickly. [3]
Solutions
20QuestionAbsorption of Nutrients in the Small IntestineAssessment Practice
3 marks~5 minCriterion C
The diagram below shows a villus from the lining of the small intestine. An arrow indicates the microvilli on the surface of an epithelial cell.
a
Describe the function of microvilli in the small intestine. [1]
b
Explain how the structure of microvilli allows nutrients to be absorbed more efficiently. [1]
c
A student claims that removing microvilli would reduce nutrient absorption but would not affect the rate of absorption. Evaluate whether this claim is correct. [1]
Solutions
21QuestionAbsorption of Nutrients in the Small IntestineAssessment Practice
2 marks~3 minCriterion D
Short bowel syndrome is a condition in which a portion of the small intestine is surgically removed, reducing the length available for digestion.
Explain the significance of villi for a patient with short bowel syndrome. [2]
Explain the significance of villi for a patient with short bowel syndrome. [2]
Solutions
22QuestionGas Exchange in the AlveoliAssessment Practice
6 marks~9 minCriterion B
The table below shows the number of alveoli and the oxygen uptake rate for three mammal species.
| Species | Mouse | Rabbit | Human |
|---|---|---|---|
| Number of alveoli (millions) | 5 | 50 | 300 |
| Oxygen uptake rate (mL /min) | 12 | 100 | 600 |
a
Describe the relationship between the number of alveoli and the oxygen uptake rate. [2]
b
A cat has 200 million alveoli. Calculate its predicted oxygen uptake rate and explain how you used the data to reach your answer. [2]
c
The actual oxygen uptake rate for a cat is 400 mL /min. Compare this value with your prediction and analyse one biological reason that could account for a difference between predicted and actual values in any species. [2]
Solutions
23QuestionBlood Vessels Arteries Veins CapillariesAssessment Practice
6 marks~9 minCriterion C
During exercise, blood flow to leg muscles increases while blood flow to the digestive system decreases. The structure of arteries and veins allows the body to redirect blood efficiently.
a
Describe two structural features of arteries that allow them to carry blood at high pressure to the leg muscles during exercise. [2]
b
Explain how the structure of veins helps return deoxygenated blood from the legs to the heart during exercise. [2]
c
A student uses a heart rate monitor during a 100-metre sprint and concludes that a higher heart rate means more blood is reaching the leg muscles. Analyse one reason why this conclusion may not be valid. [2]
Solutions
24QuestionBlood Vessels Arteries Veins CapillariesAssessment Practice
8 marks~12 minCriterion D
A biomedical engineering firm is developing a synthetic blood vessel for heart bypass surgery. The vessel must withstand high pressure and pulsatile (rhythmic) blood flow near the heart.
a
Compare the wall structure of arteries and veins. Give two structural differences in your answer. [2]
b
Explain why the synthetic vessel should be designed to mimic an artery rather than a vein. [2]
c
The firm plans to test the synthetic vessel on animals before human trials. Analyse the ethical implications of this decision, considering both animal welfare and the potential benefit to human health. [4]
Solutions