In the Pressure-Flow Mechanism, Loading of Sucrose from Companion Cells

question 51

Multiple Choice

In the pressure-flow mechanism, loading of sucrose from companion cells to sieve-tube elements requires which of the following?

• A) plasmodesmata
• B) facilitated diffusion
• C) sucrose-K+ symporters
• D) sucrose-H+ antiporters

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Definitions:

Reversed-Treatment Pretest-Posttest Design

A research design where participants receive treatments in reverse order across two periods, allowing the examination of treatment effects over time.

Selection-By-Maturation Interaction

A potential threat to internal validity in experiments, caused when differences between groups change over time in a way that affects the dependent variable.

Pretest Sensitization

The effect that participation in a pretest may have on subjects' behavior in subsequent phases of a study, potentially biasing the results.

Time-Series Designs

Research methods that involve repeated observations of the same variables (e.g., individuals) over short or long periods of time.