Chemistry for Biologists

Gas exchange

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

 

RSC