Chemistry for Biologists

Gas exchange

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

 

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