2e) Structure of Leaf Flashcards
Word & symbol equation for photosynthesis
Carbon Dioxide + Water -> glucose + oxygen
6CO2 + 6H2O -> C6H12O6 + 6O2
Where does photosynthesis occur?
Chloroplasts in plants
What are the uses of glucose in plants?
Glucose is transported as starch
Glucose is stored as starch
Glucose is used as cellulose for cell walls
For respiration
How does CO2 concentration affect rate of photosynthesis?
It increases rate of photosynthesis up to a point because more CO2 is available for the reaction.
It then levels off because of limiting factors.
How does light intensity affect rate of photosynthesis
It increases rate of photosynthesis up to a point since more light means more energy for the reaction.
It then levels off because of limiting factors.
How does temperature affect rate of photosynthesis
It increases rate of photosynthesis up to a point since it allows enzymes to work at their optimum temperature.
It then levels off because enzymes are denatured
How is the waxy cuticle adapted for photosynthesis?
A thin layer of lipids that prevents water loss but allows light through
How is the upper epidermis adapted for photosynthesis?
It is transparent to allow light pass through
A protective layer to prevent pathogen entry.
How is the Palisade Mesophyll adapted for photosynthesis?
Tall, thin cells packed closely together
Contains a large amount of chloroplasts.
Therefore max. absorption of light for photosynthesis
How is the spongy mesophyll adapted for photosynthesis?
Spongy so there are large air spaces
This allows gases to circulate in the leaf.
CO2 for P and O for R can diffuse to the cells
CO2 can diffuse out
How is the lower epidermis adapted for photosynthesis?
Has pores called stomata to allow carbon dioxide into the leaf. Guard cells can close stomata to reduce water loss.
What is the function of xylem?
Brings water to the leaf from the soil, which is needed for photosynthesis.
What is the function of phloem?
It takes some of the products of photosynthesis to other parts of the plant for utility & storage
Describe the structure of xylem
They are long, hollow structures consisting of dead cells with no cytoplasm for an uninterrupted flow of water.
Walls are strengthened with lignin which provide support.
Describe the structure of phloem
Sieve tube cells are supplied with energy by companion cells.
Cytoplasm connects sieve tube cells to form a sieve tube.
Contents can travel up or down the plant
Describe how guard cells open and close stomata.
When the guard cells are turgid, they buckle, so a hole is formed for gas diffusion.
When the guard cells are flaccid, they go back to their original position, closing the stomata
When do stomata open/close and why?
They open during the day so gases and water can diffuse into the leaf for P.
They close during the night to prevent transpiration.
