Gas Exchange in Plants Flashcards
what are the three key layers of a dicotyledonous leaf
palisade mesophyll
spongy mesophyll
stomata
where are the stomata found
on the lower side of the leaf
what is the stomata
the site of gas exchange in a leaf
what are the cells on either side of the stomata called
guards cells
where does carbon dioxide diffuse into through the stomata
spongy mesophyll layer
where does carbon dioxide diffuse through to from the spongy mesophyll
palisade mesophyll
how do you identify the spongy mesophyll in a diagram
there will be loads of gaps throughout the layer
what is the vascular bundle
where the xylem and phloem are
how do you identify the palisade mesophyll layer in a diagram
layer of longer, narrower cells
why is the palisade mesophyll layer packed with chloroplasts
to maximise the amount of chlorophyll for light absorption
what gas diffuses into the stomata
carbon dioxide
what gases diffuse out of the stomata
oxygen
how do the stomata reduce water loss by evaporation
the guard cells close at night when photosynthesis isnt occuring
if the guard cells are swollen the stomata are open/closed
open
if the guard cells are shrunken the stomata are open/closed
closed
what are xerophytic plants
plants that have to adapt to live in dry arid conditions
what structural features do xerophytic plants have to efficiently exchange gases whilst limiting water loss
curled leaves
hair like structures
sunken stomata
thicker cuticle
longer root network
how is curled leaves aiding efficient gas exchange in xerophytic plants
water that manages to evaporates, is trapped within the curl so the area becomes very humid > reduces the water potential gradient from inside to outside of plant which reduces further evaporation
how do the spikey hair like structures aid efficient gas exchange in xerophytic plants
they help to trap the water within the curl > increases humidity > reduces water potential gradient from the inside to outside of the leaf > reduces further evaporation
how is sunken stomata aiding efficient gas exchange in xerophytic plants
helps trap moisture > increase in humidity > reduces water potential gradient from inside to outside of the cell > reduces further evaporation
how is a thicker cuticle aiding efficient gas exchange in xerophytic plants
reduces evaporation
how does having a longer root network aid efficient gas exchange in xerophytic plants
allows the roots to reach out to longer distances top reach more water
