Leaf Structure And Function

Front 1

Vascular Bundle

Back 1

veins of the leaf

transport water and photosynthetic products

Front 2

Palisade Mesophyll

Spongy Mesophyll

Back 2

Palisade Mesophyll
- top of leaf
- column cells
- sunlight capture

Spongy Mesophyll
- spongier
- air diffuses through leaf here
- stomata

Front 3

Stomata

Back 3

- stomatal pore + guard cells
allow for co2 diffusion into leaf
-pores open to allow for h2o to diffuse through leaf
- turgid = open

Front 4

Guard cell

Back 4

only cell on epidermis with chloroplast:
- to sense light and because it requires ATP to open and close g. cell

To OPEN:
- H+ ions pumped out of guard cell
- K+ ions in
- This lowers water potential of cell, causing water to flow in due to osmotic gradient
- Makes it turgid, pore opens

Front 5

What happens under hot, arid conditions in terms of the stomata and water loss?

Back 5

Leaves lose water by evaporation through stomatal openings.

The stomata close to conserve water but this creates a build up of oxygen, and co2 cannot enter leaves.

Front 6

Non-Glandular Trichomes

Back 6

Epidermal hairs trap a boundary layer of air against the leaf surface, preventing the loss of moisture and heat

non secretary, just physical structure

provides barrier against insects and herbivores

found in dry, arid , warm places

Front 7

Glandular Trichomes

Back 7

Secretes toxic and nasty tasting subtstances to ward off herbivores

Front 8

Leaf Vascular System

Back 8

contain xylem and phloem

transports water and photosynthesis products around the plant

Front 9

What is photorespiration?

Back 9

O2 competes with co2 for binding site on rubisco

Rubisco fixing o2 = co2 released --> reverses calvin cycle

Always occurs in sunlight

Front 10

When is photorespiration a problem?

Back 10

This is a problem in hotter places, cause the stomata stays closed --> co2 depletion, but heaps of o2

Front 11

C4 Photosynthesis...

Back 11

Goal is to get around photorespiration.

Fixes co2 into a 4 carbon product, which is moved to the bundle sheath

Co2 is then removed and processed in the calvin cycle. 3 carbon molecule is recyled to the mesophull

Front 12

CAM Photosynthesis

Back 12

during the night, stomata opens, takes in co2, and converts it to malate and stores in vacuole

during the day, keeps stomata closed, liberators co2 from malate and runs calvin cycle.

Front 13

What enzyme does C4 and CAM Photosynthesis use?

Back 13

PEP Carboxylase

This does not react with oxygen, hence it is more efficient in warm conditions.

Front 14

Isobilateral Leaves

Back 14

Isobilateral leaves hang vertically and have palisade mesophyll on both sides
Distribution of stomata is even across both surfaces

minimises heat

opposite is dorsiventral

Front 15

Heterophylly

Back 15

possession of two diff leaf types on one plant