4.3 - Structure of the Leaf Flashcards
Why does it have a large Surface Area?
To enable it to collect the maximum amount of sunlight.
How are the leaves arranged?
They are arranged so as to minimise overlapping and shadowing other leaves.
Why are leaves thin?
Because most light is absorbed within the first few mm’s of the leaf - hence a short diffusion distance.
What enables light to pass through to the mesophyll cells?
A transparent cuticle and epidermis.
What are mesophyll cells?
Long and narrow cells that contain many chloroplasts to collect sunlight for photosynthesis.
What is special about the stomata?
There are many for gaseous exchange. Also, they open and close with light intensity.
Why are there many air spaces in the lower mesophyll?
To allow diffusion of Carbon Dioxide and Oxygen.
What does the xylem do?
It carries water to the leaf cells.
What does the phloem do?
It carries the sugars produced in photosynthesis away from the leaves.
What are the grana, and where are they found?
stacks of up to 100 thylakoids.
What is the stroma, and what process is it used in?
Fluid-filled matrix inside the chloroplast. Used in LIR. Contains the grana among other things.
What are thylakoids, and what process are they used in?
Disc-like structures that contain the photosynthetic pigment chlorophyll. They are used in the LDR.
