Chemistry for Biologists

Gas exchange

1. Withdrawing potassium ions from guard cells:
reduces water potential
has no effect on the stoma
closes the stoma
opens the stoma
2. The plant hormone that triggers potassium ion withdrawal from guard cells
acetic acid
amino acid
abscissic acid
ascorbic acid
3. Gases flow in and out of leaves by the process of:
diffusion
hydrolysis
electrolysis
osmosis
4. The effect of adding potassium ions on the water potential in guard cells is:
the water potential decreases
the water potential is unaltered
the water potential is exactly zero
the water potential increases
5. Water flows in and out of the guard cells by the process of:
diffusion
electrolysis
osmosis
hydrolysis
6. Stomata close when guard cells:
contain no water
are turgid
are not turgid
contain no potassium ions
7. The ions transported into guard cells to close the stomata are:
OH-
Na+
K+
Cl-
8. The inner walls of stomata are held rigid by:
cellulose microfibrils
spongy mesophylls
palisade mesophylls
sclerenchyma
9. When guard cells fill up with water they are said to become:
turgid
turbid
turbulent
traumatized
10. Stomata are situated in the gaps between:
palisade cells
guard cells
xylem cells
phloem cells

 

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