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CAIE IGCSE Biology 8.4 Translocation Questions

Practise translocation questions on sucrose and amino acid movement in phloem, source-sink decisions, seasonal organ roles and girdling evidence.

Syllabus
2026–2028
Course
Biology 0610

Exam points

  • Explain translocation as phloem movement of sucrose and amino acids, rather than water or maltose, between plant organs.
  • Classify leaves, storage organs and growing tissues as sources or sinks by deciding whether they release, use or store assimilates.
  • Explain seasonal source–sink reversals by tracing assimilates from storage organs to shoots and later from leaves to storage.

Covered syllabus points

8.4.1—Translocation as the movement8.4.2—Describe: (a) sources as the parts8.4.3—Some parts of a plant may act

Question 1

[Maximum number: 2]

Question (a)

(a)

Fig. 6.1 is a diagram showing some parts of a plant. The circle shows a magnified cross-section of part of the stem.

Fig. 6.1

Fig. 6.1

[ 2 ]

Question (i)

(i)

State the name of the process that describes the transport of sucrose in a plant.

[ 1 ]

Question (ii)

(ii)

State one letter from Fig. 6.1 that is a structure that is an example of a source for sucrose transport.

[ 1 ]

Question 2

[Maximum number: 4]

Aphids are arthropods.
Aphids insert their mouthpieces into the phloem in the stem of a plant to feed.
An aphid is shown in Fig. 2.1.

Fig. 2.1

Fig. 2.1

magnification ×22\times 22

Fig. 2.3 shows a potato plant growing in the spring and then in the summer.

Fig. 2.3

Fig. 2.3

Explain how translocation changes between spring and summer in the potato plant shown in Fig. 2.3.

Use the terms source and sink in your answer.

Question 3

[Maximum number: 1]

Which statement describes the process of translocation?

A

the movement of sucrose and amino acids in the xylem from the source to the sink

B

the movement of sucrose and water in the phloem from the sink to the source

C

the movement of sucrose and amino acids in the phloem from the source to the sink

D

the movement of water and amino acids in the xylem from the source to the sink

Question 4

[Maximum number: 1]

Fig. 6.1 is a diagram showing some parts of a plant. The circle shows a magnified cross-section of part of the stem.

Fig. 6.1

Fig. 6.1

State the name of the process that describes the transport of sucrose in a plant.

Question 5

[Maximum number: 1]

Fig. 6.1 is a diagram showing some parts of a plant. The circle shows a magnified cross-section of part of the stem.

Fig. 6.1

Fig. 6.1

State one letter from Fig. 6.1 that is a structure that is an example of a source for sucrose transport.

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