Why study photosynthesis?

Environment

• Source of earth’s oxygen

• Uses carbon dioxide to prevent greenhouse gases

Agriculture• Food

• Sugar cane most efficient plant

Energy Production• Ethanol and fuels

Electronics

• Solar power• Light-based computer

chips

Medicine/Health Care

• Natural sunscreens• Cures for disease• Skin care

Fiber/Materials

• Clothes• Construction• Paper, wood

What is Photosynthesis

(Sunlight and chlorophyll)

C02 + H20------------------- C6H1206 + 02

Carbon dioxide + water makes glucose + oxygen

Where does it take place?

Chloroplasts in leaves

Assignment

• Fold a piece of paper into thirds

• Draw and color a LEAF (See Figure 23-18, pg. 596). Label the veins.

• Draw and color the LEAF CROSS SECTION on pg. 596.

• Label the spongy mesophyll, guard cells, cuticle, upper epidermis, palisade mesophyll, xylem, phloem, vein, lower epidermis, stoma.

• Draw and color the CHLOROPLAST on pg. 208.

• Label the stroma, granum, thylakoids.

• It should look like this:

Leaf Cross-section

chloroplast

Leaf cross-section“Pathway of Photosynthesis”

C02 + H20------------------- C6H1206 + 02

Cuticle-waterproof, waxy coating; protects leaf from water loss

cuticle

Epidermis- cube shaped cells; outermost layer; upper and lower

LIGHT ENTERS HERE

Upper epidermis

Lower epidermis

Mesophyll includes:

Palisade layer- tall columnar shaped cells: CONTAIN CHLOROPLASTS

Palisade layer

Mesophyll includes:Spongy layer – cells arranged with air spaces – OXYGEN AND C02 ENTER

AND LEAVE HERE

Spongy Mesophyll

Vascular bundle-veinXylem-WATER moves UP to

leaves FROM ROOT

Xylem

Vascular bundlePhloem-FOOD moves DOWN to

ROOTS

Phloem

Stomata- opening to allow water and GAS exchange

stomata

Guard Cells-regulates opening of stomata according to water

pressure

Guard cells