Plant Organisation - The Leaf

What is a leaf?

The leaf is a plant organ adapted specifically for photosynthesis

What is on top of the leaf structure?

waxy cuticle

What is below the top waxy cuticle?

upper epidermis

What is below the upper epidermis?

palisade mesophyll layer

What is below the palisade mesophyll?

spongy mesophyll

What is below the spongy mesophyll?

lower epidermis

What is part of the lower epidermis layer?

guard cells

What is above the guard cells?

air space

What runs through the side of the spongy mesophyll layer?

vascular bundle (xylem and phloem)

structure of a leaf

here

What are some adaptions of the leaf? (10)

Large surface area, thin, chlorophyll, network of veins, stomata, epidermis is thin and transparent, waxy cuticle, palisade layer at top of leaf, air spaces, vascular bundle

purpose of large surface area as an adaption?

Increases surface area for the diffusion of carbon dioxide and absorption of light for photosynthesis

purpose of thin as an adaption?

Allows carbon dioxide to diffuse to palisade mesophyll cells quickly

purpose of chlorophyll as an adaption?

Absorbs light energy so that photosynthesis can take place

purpose of vein network as an adaption?

Allows the transport of water to the cells of the leaf and carbohydrates from the leaf for photosynthesis (water for photosynthesis, carbohydrates as a product of photosynthesis)

purpose of the stomata as an adaption?

Allows carbon dioxide to diffuse into the leaf and oxygen to diffuse out

purpose of thin and transparent epidermis as an adaption?

Allows more light to reach the palisade cells

purpose of waxy cuticle as adaption?

to protect the leaf without blocking sunlight

purpose of palisade layer at top as an adaption?

Maximises the absorption of light as it will hit chloroplasts in the cells directly

purpose of air spaces in the spongy layer as an adaption?

Air spaces allow carbon dioxide to diffuse through the leaf, increasing the surface area

purpose of vascular bundle as an adaption?

Thick cell walls of the tissue in the bundles help to support the stem and leaf

what is the purpose of the structure of the leaf?

The structure of a leaf maximises the diffusion of carbon dioxide into the mesophyll cells for photosynthesis

What is the pathway of carbon dioxide in the leaf?

1. in the atmosphere: higher concentration of carbon dioxide compared to inside the leaf

2. co2 diffuses into leaf through open stoma into air space in spongy mesophyll

3. co2 diffuses through cell wall + cell membrane of mesophyll cell, dissolves in the cytoplasm + diffuses into chloroplast

What does the structure of the leaf enable?

The structure of a leaf enables air to circulate within it to maximise the diffusion of carbon dioxide to the chloroplasts for photosynthesis