Chemistry for Biologists

Gas exchange

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

 

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