Leaves & Photosynthesis

Leaf Structure

What do leaves do? Photosynthesis Regulate water loss Gas exchange

This means they make their own food. Plants are Autotrophs!! This means they make their own food. Plants make their own food via photosynthesis.

What is photosynthesis? A process in autotrophs where radiant energy (sunlight) is converted to chemical energy (glucose)for cellular respiration

Photosynthesis Equation Photosynthesis uses sunlight energy to convert water (H2O) and carbon dioxide (CO2) into high energy sugars and oxygen. (light) Carbon Dioxide + Water Sugar + Oxygen 6 CO2 + 6 H2O C6H12O6 + 6 O2

Leaves have 2 structure that help regulate water loss. Regulating Water Loss Leaves have 2 structure that help regulate water loss. Cuticle Waxy layer (what biomolecule is a wax) Stomata Structure that opens and closes to help regulate water evaporation.

Stomata Structure

Guard Cells Specialized cells that surround the stomata and control the opening and closing of the stomata. When the plant needs to close the stomata, the guard cells are filled with water, which swells them until the stomata are sealed shut. When the plant is ready to open the stomata, the guard cells are drained, which creates an opening called a pore.

Stomata Function Photosynthesis Cellular Respiration Transpiration CO2 in and O2 out Cellular Respiration O2 in and CO2 out Transpiration H2O out Pulls on water from the roots

What is Transpiration? Transpiration occurs when plants release water vapor through the stomata, which results in additional water being pulled up through the stem and circulated through the plant for use in photosynthesis.

What is Transpiration? When there is little water, the stomata remain closed in order to conserve moisture. When the stomata are closed due to a water shortage photosynthesis cannot occur because the plant is not taking in carbon dioxide.

Benefits of stomata The unique structure of the stomata makes the plant more efficient and better able to cope during different environmental conditions. Less advanced plants, such as the liverwort, do not have stomata. These plants have continuously open pores, and therefore can only survive in extremely wet environments. The use of stomata, however, allows plants to survive in many different types of climates.