Welcome to the Quiz!
This quiz contains 10 questions from a mix of 1 subtopics.
How do radioactive tracers provide evidence for the mass flow hypothesis?
they show that organic substances move from source to sink
they show that inorganic substances move from source to sink
they show that organic substances move from sink to source
they show that organic substances do not move through the plant
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Which of the following is NOT evidence supporting the mass flow hypothesis?
aphid feeding
radioactive tracers
sugars moving to sinks with the highest water potential
ringing experiments
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What is the primary purpose of translocation?
to maintain a concentration gradient using enzymes
to move water through the xylem
to transport dissolved sugars and amino acids through the phloem
to actively load solutes into companion cells
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According to the mass flow hypothesis, what happens at the source to initiate translocation?
water exits the sieve tube elements by osmosis
solutes are actively removed from sieve tube elements
solutes like sucrose are actively loaded into sieve tube elements
hydrostatic pressure decreases in the 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 decreases
it fluctuates
it increases
it remains unchanged
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According to the mass flow hypothesis, what creates the pressure gradient that drives translocation?
(Select all that apply)
active loading of solutes at the source and removal of solutes at the sink
diffusion of solutes through plasmodesmata into companion cells from sieve tube elements at the source
osmosis of water out of sieve tube elements at the source and in at the sink
movement of water by osmosis into sieve tube elements at the source and out at the sink
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Which of the following is NOT a feature of translocation?
it transports substances from sources to sinks
it occurs through the xylem
it maintains a concentration gradient using enzymes
it requires energy
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What happens to the hydrostatic pressure in sieve tube elements at the source during translocation?
it remains unchanged
it decreases
it increases
it fluctuates
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Which of the following is a source of assimilates for translocation?
stems
flowers
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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