Welcome to the Quiz!
This quiz contains 9 questions from a mix of 1 subtopics.
What is the primary purpose of translocation?
to actively load solutes into companion cells
to move water through the xylem
to transport dissolved sugars and amino acids through the phloem
to maintain a concentration gradient using enzymes
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According to the mass flow hypothesis, what happens at the source to initiate translocation?
solutes are actively removed from sieve tube elements
hydrostatic pressure decreases in the sieve tube elements
water exits the sieve tube elements by osmosis
solutes like sucrose are actively loaded into sieve tube elements
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What happens to the water potential in sieve tube elements when solutes are actively loaded at the source?
it remains unchanged
it fluctuates
it increases
it decreases
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According to the mass flow hypothesis, what creates the pressure gradient that drives translocation?
(Select all that apply)
osmosis of water out of sieve tube elements at the source and in at the sink
active loading of solutes at the source and removal of solutes at the sink
movement of water by osmosis into sieve tube elements at the source and out at the sink
diffusion of solutes through plasmodesmata into companion cells from sieve tube elements at the source
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Which of the following is NOT a feature of translocation?
it maintains a concentration gradient using enzymes
it occurs through the xylem
it requires energy
it transports substances from sources to sinks
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What happens to the hydrostatic pressure in sieve tube elements at the source during translocation?
it fluctuates
it remains unchanged
it decreases
it increases
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Which of the following is a source of assimilates for translocation?
flowers
stems
leaves
roots
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Explain how the mass flow hypothesis proposes that translocation occurs, including the roles of the source and sink.
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How are hydrogen ions (H+) involved in the active loading of sucrose into the phloem?
H+ is co-transported with sucrose into companion cells
H+ is not involved in the active loading of sucrose
H+ is actively transported into companion cells from surrounding source cells
H+ diffuses through plasmodesmata from companion cells to sieve tube elements
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