15. Chloroplasts and guard cells

What can chloroplasts do?

Rotate and move in mesophyll cells -> Can arrange themselves in best position for light absorption

What allow exchange of gases in plants?

Pores called stomata (stoma (s))

What can also be lost via the stomata?

Water

What is each pore bounded by?

Each pore bounded by 2 guard cells

What do guard cells have inside?

Chloroplasts, unlike epidermal cells

What do guard cells have? (not chloroplasts)

Thick inner wall and thin outer wall -> causes cell to become curved sausage shaped when cell swells

What does the guard cell becoming curved cause?

Causes stomatal pore to open

What can guard cells do?

Change shape to open and close the stomata, controlling gas exchange + water loss

Where are most stomata found? Why?

Lower leaf side to reduce water loss as they’re in the shade which reduces evaporation

What do most stomata do at night? Why?

Close to prevent plant losing water when light intensity is too low for photosynthesis