6.2 Leaf Structure (Cambridge (CIE) O Level Biology): Flashcards
Exam code: 5090
1/220Still learning
Know0
- FrontLeaf Structure
What is the function of a leaf?
Was this flashcard helpful?
Cards in this collection (22)
What is the function of a leaf?
It is the plant organ that carries out photosynthesis.
Give two ways a leaf is adapted for photosynthesis.
A large surface area to absorb more light
Thin, so gases can diffuse quickly to and from the cells
Why do leaves have a large surface area?
To maximise the absorption of light for photosynthesis.
Why are leaves thin?
To allow the efficient (quick) diffusion of gases between the leaf cells and the surrounding air.
A leaf's large area maximises the absorption of light for photosynthesis.
A leaf's large surface area maximises the absorption of light for photosynthesis.
True or False?
Being thin helps carbon dioxide diffuse quickly to the photosynthesising cells.
True.
A thin leaf gives a short diffusion distance, so carbon dioxide reaches the cells rapidly.
The leaf is a plant adapted to carry out photosynthesis.
The leaf is a plant organ adapted to carry out photosynthesis.
How does a leaf's shape help carbon dioxide reach the photosynthesising cells?
It is thin and flat, giving a short diffusion distance so carbon dioxide diffuses in quickly.
Define palisade mesophyll.
A layer of tightly packed, column-shaped cells near the upper surface of the leaf, containing many chloroplasts for photosynthesis.
Define spongy mesophyll.
A layer of loosely packed photosynthesising cells with air spaces that allow gases to move easily.
Define stomata.
Pores (mostly on the lower leaf surface) that allow gases and water vapour to diffuse in and out of the leaf.
Define guard cells.
Cells surrounding each stoma that change shape to open or close it, controlling gas exchange and water loss.
What is the function of the waxy cuticle?
A transparent layer that protects the leaf and reduces water loss by evaporation, while still letting light through.
What does the xylem transport, and how does this help the leaf?
Water — providing water for photosynthesis and maintaining the transpiration stream.
What does the phloem transport?
Sucrose and amino acids away from the leaf to other parts of the plant.
Why is the upper epidermis transparent?
To allow light to pass through to the palisade and spongy mesophyll cells below.
Most plants have more stomata on the surface of the leaf.
Most plants have more stomata on the lower surface of the leaf.
How is the palisade mesophyll adapted for photosynthesis?
Column-shaped cells are packed tightly in a single layer near the top of the leaf, each with many chloroplasts, to maximise light absorption.
The waxy reduces water loss from the upper surface of the leaf.
The waxy cuticle reduces water loss from the upper surface of the leaf.
What is the role of the air spaces in the spongy mesophyll?
They allow the easy movement (diffusion) of gases through the leaf.
True or False?
Guard cells can close the stomata to reduce water loss.
True.
Guard cells change shape to close the stomata, reducing water loss from the leaf.
Define the vascular bundle.
The structure in a leaf that contains the xylem and phloem, delivering water and removing sugars.
Sign up to unlock flashcards
or