12.2 Leaves Flashcards
1
Q
Leaves important functions for the plant
A
- Protection: contain pigments, tannins, and caffeine that prevent herbivores from eating
- Photosynthesis
- Gas exchange: Release of O2 and intake of CO2 on the surface or epidermis which is porous
2
Q
Why the leaves are important
A
- Where photosynthesis occurs
- Leaves absorb sunlight, a specific organelle called chloroplasts
- Each chloroplast contains photopigments
- This defies the type of light absorbed/reflected by
the leaf - Often red or blue are absorbed, green reflected
- This defies the type of light absorbed/reflected by
3
Q
External structures of the leaf
A
Blade
Petiole
Leaflets
Veins
4
Q
Blade
A
Flat part of the leaf
5
Q
Petiole
A
Stalk attaching leaf blade to stem
6
Q
Leaflets
A
Multiple bladed plant
7
Q
Veins
A
Sub stems attaching to petiole
8
Q
How the leaves support photosynthesis and gas exchange
A
- Cuticle: waxy coating layer preventing water loss and physical barrier from external harm
- Upper epidermis: first layer of cells, transparent so light can travel through for photosynthesis
9
Q
Photosynthesis occurs in…
A
- the mesophyll (middle layer)
10
Q
Two parts of the mesophyll
A
- Palisade mesophyll
- Spongy mesophyll
11
Q
Palisade mesophyll
A
- Layer of elongated cells arranged under the upper surface, contains chloroplasts (elongated to maximize sunlight exposure)
12
Q
Spongy mesophyll
A
- Layer of loosely packed cells, large air spaces to allow for gas exchange with environment
13
Q
How do the gases get out?
A
- Stoma (plural stomata): opening in the leaves to allow gases in and out
- Guard cells: control the opening and closing of the stomata
14
Q
4 Human uses of leaves
A
- provides nutrients and energy
- furniture polish
- religious ceremonies
- psychotropic drugs
15
Q
- provides nutrients and energy
A
- dark leafy greens (spinach) that contain minerals (Ca, K, Fe, and Mg) and vitamins B, C, E and K
