Leaves Flashcards
When does the stomata tend to close ?
Low water availability or low sunlight
When does the stomata tend to open ?
Plenty of water and sunlight
When does the stomata close ?
When the guard cells lose water to the neighboring epidermal cells and they become flaccid (limp)
When does a stomata open ?
When water moves by osmosis into the guard cells causing them to become turgid ( swollen and hard )
What happens to oxygen and any excess water vapour not used during photosynthesis?
They diffuse out of the leaf
What is the purpose of the stomata ?
To allow the diffusion of gases
What do guard cells do ?
They are on either sides of a stomata and they are responsible for the opening and closing of a stomata
What is the stomata ?
Pores or spaces mostly found on the lower epidermis of the leaf
What is the function of xylem vessels ?
To transport water and minerals to the palisade layer
What is the function of Palisade cells that are packed with chloroplast?
Absorb light
What is the function of close contact between the cells and the air spaces?
Allowed efficient gas exchange for photosynthesis and respiration
What is the function of moist air?
Gases can dissolve into it for easier movement in and out of the cells
What is the function of the thin cell walls ?
Allow gases to move in and out of the cells easily
What is the function of the stomata in the lower epidermis?
Open in sunlight to allow gas movement in and out of the leaf
What is the function of air spaces ?
Allow gas movement around the loosely packed mesophyll cells
What are the internal leaf adaptations?
Air spaces
Many stomata people in the lower epidermis
Thin cell walls
Moist air
Close contact between the cells and the air spaces
Palisade cells that are packed with chloroplast
Xylem vessels
What is the function of the upper epidermis ?
Transparent to allow sunlight to reach the palisade layer
What is the function of a waxy cuticle ?
To prevent excessive water loss through evaporation
What is the function of leaves having many stomata?
Allow movement of gases in and out of the air spaces inside the leaf by maintaining a steep concentration gradient
What is the function of thin leaves ?
Gives a short diffusion distance of gases
What is the function of leaves being broad and flat ?
Giving them a large surface area to capture light
What are the external adaptations of a leaf ?
Broad and flat
Thin leaves
Many stomata
Waxy cuticle
Upper epidermis
What are categories of leaf adaptations to carry out photosynthesis?
Internal adaptations and External adaptations
What is the Spongy mesophyll layer ?
Found below the Palisade layer
This contains air spaces which allows CO2 to diffuse to the palisade layer and O2 to diffuse out
What is the palisade mesophyll layer?
Found at the top of the leaf
Packed with many cells that contain chloroplast
This is where most of a plant’s photosynthesis occurs
What are the 2 layers of the leaf ?
Palisade mesophyll layer and Spongy mesophyll layer
How many layers is the leaf divided into ?
2
