IB Diploma · Biology B3.2
IB Biology B3.2: Transport — Practice Questions & Answers
IB Biology B3.2 study notes: the circulatory system, heart, blood vessels, and transport of water and sugars in plants.
Here are 10 practice questions with full answers and explanations.
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Practice questions with answers
1
Multiple choice
What is the function of fenestrations in some capillaries?
- Facilitate rapid exchange of materials.
- Prevent blood flow.
- Store blood cells.
- Reduce blood pressure.
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WhyFenestrations are pores that speed exchange of fluids and small solutes between blood and tissues.
2
Multiple choice
How can arteries and veins be distinguished in micrographs?
- By the structure and thickness of their vessel walls relative to the lumen
- By the color of the blood
- By the presence of fenestrations
- Veins always appear perfectly circular in cross-section due to higher blood pressure
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WhyArteries have thick muscular walls and narrow lumens, whereas veins have thinner walls and wider lumens.
3
Multiple choice
What adaptation of arteries helps them withstand high blood pressures?
- Layers of muscle and elastic tissue in their walls.
- Thin walls.
- Presence of valves.
- Large lumen.
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WhyThick muscular and elastic layers let arteries stretch and recoil, withstanding high, pulsing blood pressure.
4
Multiple choice
How is heart rate determined by feeling the pulse?
- By feeling the carotid or radial pulse with fingertips
- By measuring blood pressure
- By listening to heart sounds
- By feeling the pulse in major veins with fingertips
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WhyCounting pulses at the carotid or radial artery gives the heart rate as beats per minute.
5
Multiple choice
What adaptation of veins prevents backflow of blood?
- Valves.
- Thick muscular walls.
- High blood pressure.
- Small lumen.
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WhyOne-way valves in veins prevent blood from flowing backwards under low venous pressure.
6
Multiple choice
What feature of vein walls allows them to be compressed by muscle action?
- Flexibility.
- Rigidity.
- Thickness.
- Lack of elastic tissue.
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WhyThin, flexible vein walls are readily compressed by surrounding skeletal muscle to aid venous return.
7
Multiple choice
What is the most immediate and direct consequence of a blockage (occlusion) in the coronary arteries?
- Reduced oxygen supply to the heart muscle, potentially leading to tissue damage (infarction)
- Increased blood pressure in the systemic circulation due to resistance in peripheral vessels
- Fluid buildup in the lungs due to the heart's inability to pump blood effectively
- Irregular heart rhythm (atrial fibrillation) and the formation of blood clots due to electrical disturbances
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WhyA coronary blockage starves cardiac muscle of oxygen, causing ischaemia and possible infarction.
8
Multiple choice
What do correlation coefficients quantify?
- Correlations between variables
- The causal relationship between two variables
- The variability of a single variable
- The statistical significance of differences between group means
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WhyCorrelation coefficients measure the strength and direction of the association between two variables.
9
Multiple choice
What does a low correlation coefficient indicate?
- Evidence against a hypothesis
- Strong causal link
- A strong linear relationship between two variables
- No relationship
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WhyA low correlation coefficient means little linear association, offering evidence against a proposed relationship.
10
Multiple choice
What causes water to be drawn up xylem vessels during transpiration?
- Tension (negative pressure potentials) generated by water loss from leaf cells.
- Active transport.
- Root pressure.
- Gravity.
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WhyWater loss from leaf cells creates tension (negative pressure) that pulls water up the xylem.
Key terms in Transport
Artery: A vessel carrying blood away from the heart at high pressure, with thick elastic and muscular walls.
Capillary: A microscopic vessel with walls one cell thick where exchange between blood and tissues occurs.
Vein: A vessel returning blood to the heart at low pressure, with valves to prevent backflow.
Double circulation: A system in which blood passes through the heart twice per circuit, with separate pulmonary and systemic loops.
Sinoatrial node: The heart’s pacemaker in the right atrium that initiates each heartbeat; the heartbeat is myogenic.
Transpiration: The loss of water vapour from a plant, mainly through the stomata, which drives the transpiration stream.
Cohesion–tension theory: The explanation that water is pulled up the xylem as an unbroken column held together by cohesion.
Xylem: Dead hollow vascular tissue that transports water and minerals upward from roots to leaves.
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