What is the movement of sucrose and amino acids in the phloem called?
Reveal answer
Translocation.
Key words: translocation
3(h) TRANSPORT · RECALL
3.3 Phloem
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Why does ringing a tree kill its roots?
Reveal answer
Phloem removed → no sucrose reaches roots → no respiration → roots die.
Key words: sucrose · phloem
Which two substances does phloem transport?
Reveal answer
Sucrose and amino acids.
Key words: sucrose · amino acids
Where does phloem carry sucrose to?
Reveal answer
From leaves (source) → to growing regions and storage organs (sinks), up or down.
Key words: up · down
What is meant by the term translocation?
Reveal answer
Transport of sucrose and amino acids in phloem.
Key words: translocation
What is meant by the term source?
Reveal answer
Tissue that loads assimilates into phloem.
Key words: source
What is meant by the term sink?
Reveal answer
Tissue that unloads and uses or stores assimilates.
Key words: sink
What is meant by the term sieve tube?
Reveal answer
Column of living conducting cells in phloem.
Key words: sieve tube
Source and sink examples: for Mature illuminated leaf, give the likely role and the reason.
Reveal answer
Likely role: Source. Reason: Exports photosynthate.
Key words: Mature illuminated leaf
Source and sink examples: for Growing root tip, give the likely role and the reason.
Reveal answer
Likely role: Sink. Reason: Uses sugars and amino acids.
Key words: Growing root tip
Source and sink examples: for Developing fruit, give the likely role and the reason.
Reveal answer
Likely role: Sink. Reason: Growth and storage.
Key words: Developing fruit
Source and sink examples: for Storage root in spring, give the likely role and the reason.
Reveal answer
Likely role: Source. Reason: Mobilises stored carbohydrate.
Key words: Storage root in spring
True or false, and why? “Phloem only transports sugar downward.”
Reveal answer
False. It transports from sources to sinks, which may lie in either direction.
True or false, and why? “Glucose is the main long-distance phloem sugar.”
Reveal answer
False. Sucrose is the principal named transport sugar.
True or false, and why? “Phloem cells are dead hollow tubes.”
Reveal answer
False. Sieve tubes are living and supported by companion cells.