Chemistry for Biologists

Gas exchange

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

 

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