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
ascorbic acid
abscissic acid
3. Gases flow in and out of leaves by the process of:
osmosis
diffusion
hydrolysis
electrolysis
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 increases
the water potential decreases
7. The ions transported into guard cells to close the stomata are:
Cl-
K+
OH-
Na+
8. When guard cells fill up with water they are said to become:
turbulent
traumatized
turbid
turgid
9. The inner walls of stomata are held rigid by:
sclerenchyma
cellulose microfibrils
spongy mesophylls
palisade mesophylls
10. Stomata are situated in the gaps between:
xylem cells
phloem cells
palisade cells
guard cells

 

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