Gas Exchange in Plants Flashcards
1
Q
palisade mesophyll features and function
A
- elongated cells so more SA for CO2 to diffuse
- main site site of photosynthesis as contains the highest density of chloroplasts
2
Q
spongy mesophyll
A
gas exchange surface
contains the vascular bundle
3
Q
waxy cuticle
A
- impermeable to water
- reduce water loss by evaporation
4
Q
epidermis in plant cells
A
- protection from mechanical damage
5
Q
air space in plant cells
A
- gas exchange
- easier to diffuse through air (gas) than cells
6
Q
stoma
A
- allows entry/exit of gases
- can close to reduce water loss by transpiration
7
Q
guard cells
A
- contains chloroplasts
- allows stomata to open and close
8
Q
gas exchange organ of plants
A
leaf
9
Q
gas exchange surface in plants
A
stomata
10
Q
xerophyte
A
a plant tht lives in an environment that has a limited supply of water and is adapted to survive there
11
Q
4 adaptations of a cactus
A
- leaves end in spines - reduce SA available for stomata, so less stomata, so less SA for transpiration
- fleshy (succulent) stem - stores water
- some have thick cuticle - reduces waer loss as more impermeable to water
- shallow, widespread roots - increases SA available for water uptake
12
Q
5 adaptations of marram grass
A
- rolled leaf - traps water molecules next to stomata, increasing humidity, reducing diffusion gradient so reducing transpiration
- leaf hairs - traps water. reducing diffusion gradient and transpiration
- sunken stomata - creates humid atmosphere outside stomata as air not moved away, reducing diffusion gradient, reducing transpiration
- fewer stomata - reduces SA for diffusion of water vapour out so reduces transpiration
- ticker waxy cuticle - reduces water loss by evaporation as more impermeable to water
13
Q
at night, what is the net movement of O2 and why?
A
net movement in as rate of PS is greater than that of RS
14
Q
in the day, what is the net movement of O2?
A
net movement out as rate of RS more than rate of PS
15
Q
gases exchanged by plants
A
- O2
- CO2
- water diffusion
