Introduction to Photosynthesis

What is Photosynthesis and Respiration? The use of carbon dioxide, water and light energy to produce organic matter and oxygen CO 2 + H 2 O + Light Energy CH 2 O + O 2 Life on Earth respires, metabolic processes that use oxygen and nutrients to generate energy and waste products CH 2 O + O 2 CO 2 + H 2 O + Energy

To carryout photosynthesis you need pigments to help absorb light Light that reaches Earth Each pigment absorbs light of different energy antonine-education.co.uk

Demo Spinach leaves and extract of the pigment Chlorophyll a Both look green under natural white light, what will happen when we shine a black (violet) light on them?

Demo Black light Both look red, why?

Shi T, Sun Y, Falkowski PG Environmental Microbiology (2007) Photosynthesis Light Energy + H 2 O + CO 2 CH 2 O + O 2

Where does photosynthesis occur?

Where does photosynthesis occur?

Land vs Ocean Vascular plants Turn over time 10 yrs 50% global production of photosynthesis Algae and cyanobacteria Turn over time 7 days 50% global production of photosynthesis

Evolution of Photosynthesis in Earth’s History Billions of Years Ago Formation of EarthFirst photosynthetic bacteriaCyanobacteriaFirst rock evidence of atmospheric oxygenRed and brown algaeGreen algaeFirst land plantsVascular plants Humans

Modified from Introduction to Atmospheric Chemistry, P. Hobbs, 2000 Effects of photosynthesis on Earth’s atmosphere

How does Photosynthesis effect biogeochemistry cycling on Earth? Carbon cycle Oxygen cycle Nitrogen cycle

Oxygen cycle