IB Biology HL B3.2 Transport Questions
Practise IB Biology HL B3.2 by linking transport structures to pressure, cardiac cycles, xylem, phloem and mass-flow evidence.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Exam points
- Explain how thin, fenestrated capillary walls permit tissue-fluid formation and exchange.
- Compare artery, vein and capillary structure to explain pressure, flow direction and exchange.
- Measure pulse rate reproducibly by timing beats at the radial or carotid artery.
- Compare single and double circulation, tracing blood flow and linking heart structures to pressure.
- Interpret ECG, pressure or heart-sound data to identify cardiac-cycle stages and valve states.
- Explain root-to-leaf water movement through xylem using transpiration pull and root pressure.
- Identify vascular bundles and xylem/phloem positions in stem and root diagrams.
- Explain phloem pressure-flow translocation using sieve tubes, companion cells and source-sink loading.
Covered syllabus points
B3.2.1—Capillary adaptationsB3.2.2—Artery and vein structureB3.2.3—Artery adaptationsB3.2.4—Pulse rate measurementB3.2.5—Vein adaptationsB3.2.6—Coronary artery occlusionB3.2.7—Water transport in plantsB3.2.8—Xylem vessel adaptationsB3.2.9—Stem tissue distributionB3.2.10—Root tissue distributionB3.2.11 (HL)—Tissue fluid in capillariesB3.2.12 (HL)—Exchange between tissue fluid and cellsB3.2.13 (HL)—Lymph ductsB3.2.14 (HL)—Single vs. double circulationB3.2.15 (HL)—Mammalian heart adaptationsB3.2.16 (HL)—Cardiac cycle stagesB3.2.17 (HL)—Root pressure generationB3.2.18 (HL)—Phloem adaptations
Question 1
Explain how the structure of capillaries relates to their functions.
Question 2
Which characteristic of the subclavian vein distinguishes it from the subclavian artery?
A
Larger lumen
B
Absence of valves
C
Presence of pores
D
Two layers of muscle
Question 3
Hypertension (blood pressure exceeding 140 mmHg ) affects millions of people worldwide. Many modern societies consume more sodium in the form of salt (NaCl) than is required for normal physiology. The effect of changing the levels of dietary sodium has been studied in various organisms.
Scientists recorded the blood pressure changes in chimpanzees (Pan troglodytes) fed a diet without added sodium (control) or a sodium supplemented diet (experimental) as follows
- 5 grams of salt per day from December 1991 until May 1992
- 10 grams of salt per day until June 1992
- 15 grams of salt per day until August 1993
after which no more salt was added to the diet until the experiment ended.
Blood pressure is measured in the arteries. Explain how arteries are adapted to withstand increases in blood pressure.
Question 4
The graph shows the relationship between the maximum heart rate during exercise and a person's age.
Outline one method that the researchers could have used to measure heart rate in this study.
Question 5
What is a reason that veins have relatively thin walls compared to arteries?
A
Allows muscle contraction to assist in blood flow
B
Prevents a blood clot forming
C
Allows exchange of materials with tissue fluid
D
Easier attachment of semilunar valves
Question 6
The rate of transpiration can be measured using a data-logging pressure sensor connected to a plant cutting via a plastic tube. In an experiment, a control set-up was connected to the tube and placed in a well-lit room with normal humidity levels.
Predict, with a reason, what will happen to the pressure in this tube as transpiration occurs.
Question 7
Ehlers-Danlos syndrome (EDS) causes joint hypermobility, where joint movement extends well beyond the normal range. Researchers used two different methods to measure angles of movement at a joint of the smallest (fifth) finger.
Joints are part of the musculoskeletal system of animals, which provides support and movement to the body. Xylem provides support in plants and also transports water and minerals.
Explain the adaptations of xylem for its functions.
Question 8
The micrograph shows a section through the root of a dicotyledonous plant .
Describe the distribution of vascular tissues in the stem of dicotyledonous plants.
Question 9
The micrograph shows a section through the root of a dicotyledonous plant .
Label tissues X and Y .
Question 10
The diagrams show blood circulation in a fish and a mammal.
Which two labels represent deoxygenated blood with the lowest pressure in each animal?
A
W and Z
B
X and Y
C
W and Y
D
X and Z
Question 11
The diagram shows a section through a human heart with the chambers, valves and main blood vessels.
What are the functions of X and Y ?
X
Y
To carry oxygenated blood to the
head and body
To prevent backflow into the aorta
when the ventricle relaxes
To carry oxygenated blood to the
head and body
To prevent backflow into the aorta
when the atrium relaxes
To carry deoxygenated blood to
the lungs
To prevent backflow into the atrium
when the ventricle contracts
To carry deoxygenated blood to
the lungs
To prevent backflow into the atrium
when the ventricle relaxes
Question 12
Many biological processes are cyclical. Examples of cycles can be found at the level of the cell, the organism and the ecosystem.
Outline the role of the right atrium in the cardiac cycle.
Question 13
(a) Explain how the pressure potential and solute potential change inside a plant root cell when it is placed into a solution that is more hypotonic than the cell's cytoplasm.
The photograph shows a seedling (young plant) of the family Fabaceae. The shoot and roots have been labelled.
Explain how root pressure is generated to cause movement of water through seedlings.
Question 14
Fluids inside unicellular and multicellular organisms allow materials to be moved.
Describe the transport of carbon compounds such as sucrose and amino acids in phloem.
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