The diagram models two connected alveoli without surfactant. Which air movement and consequence are predicted?
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The diagram models two connected alveoli without surfactant. Which air movement and consequence are predicted?
Stomatal aperture and xylem flow were unchanged. What explains the carbon-dioxide uptake results?
| Mesophyll air spaces | Carbon-dioxide uptake / μmol m⁻² s⁻¹ |
|---|---|
| gas-filled | 12 |
| water-filled | 2 |
| gas-filled after water removal | 13 |
How does the spongy mesophyll support gas exchange in plant leaves?
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Nerves to inspiratory muscles were selectively blocked; stimulation intensity was unchanged. Which contributions to thoracic volume are supported?
| Nerve block | Increase in thoracic volume / dm³ |
|---|---|
| none | 1.2 |
| diaphragm | 0.4 |
| external intercostal | 0.8 |
| both | 0.0 |
A pathogen fills Y with fluid but does not damage cells. Which process is most directly limited?
Y to X; collapse of X
X to Y; collapse of Y
No net movement; neither alveolus collapses
X to Y; collapse of X
Gas-filled spaces provide low-resistance diffusion to mesophyll
Water-filled spaces accelerate diffusion to mesophyll
Xylem supplies most carbon dioxide directly to mesophyll
Water irreversibly damages mesophyll photosystems