Chemistry for Biologists

Gas exchange

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

 

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