gas exchange in dicotyledonous plants

Question 1

How do plants prevent water evaporation

Answer 1

waxy cuticle

Question 2

which cell layer is the site of photosynthesis

Answer 2

palisade cell layer

Question 3

which layer allows for gas diffusion

Answer 3

spongy mesophyll layer

Question 4

what is a dicotyledonous plant

Answer 4

a type of flowering plant with 2 seed leaves

Question 5

what are the stomata

Answer 5

tiny openings on the under side of the leaf which have guard cells on either side

Question 6

what happens to the stomata during the day

Answer 6

the guard cells on either side of the stomata fill with water via osmosis which makes the turgid causing the stomata to open. as a result carbon dioxide can entre the leaf for photosynthesis and oxygen can diffuse out.

Question 7

what happens to the stomata at night

Answer 7

the guard cells on either side of the stomata empty of fluid via osmosis which makes the flaccid causing the stomata to close

Question 8

what is the role of potassium in the opening of the stomata

Answer 8

when light intensity is high potassium ions move into the guard cells. This causes more water to move in via osmosis which leads to the cell becoming turgid. However because the inner walls is less flexible than the outer walls it swells unevenly creating a small open pore in between the two guard cells.

Question 9

what is plasmolysis

Answer 9

detachment of plasma membrane from cell wall as cytoplasm shrinks

Question 10

reducing water loss in plants

Answer 10

-waxy cuticle= reduces water loss due to evaporation through the epidermis
-stomata location= under surface of the leaf to minimise evaporation due to sunlight
-stomata closes at night