Topic 5 Notes

Photosynthesis

The conversion of light energy to chemical energy.

Autotrophs

Organisms that produce their own food from simple substances in their surroundings.

Heterotrophs

Organisms unable to make their own food, relying on other organisms for sustenance.

Cyanobacteria

Early prokaryotic organisms capable of photosynthesis that oxygenated Earth's atmosphere.

Chloroplast

Organelle where photosynthesis occurs, found in the mesophyll of leaves.

Stomata

Pores in leaves that allow CO2 to enter and O2 to exit.

Thylakoids

Membranous structures within chloroplasts that form stacks known as grana.

ATP (Adenosine Triphosphate)

A molecule that carries energy within cells, produced during the light reactions of photosynthesis.

Calvin Cycle

The set of biochemical reactions in photosynthesis that reduces CO2 to sugar (G3P) using ATP and NADPH.

Photorespiration

A process occurring in hot conditions where plants close stomata, leading to reduced CO2 and increased O2, resulting in no sugar production.