BIO251H1 Lecture Notes - Lecture 2: Oryza, Ribulose, Succulent Plant
Document Summary
Human society is dependent upon photosynthesis for its food and energy needs. All life ultimately depends on the transformation of physical energy to biologically useful energy stored in molecules such as atp and nadph. There are two forms of physical energy available to life on earth, both of which are ultimately derived from nuclear reactions. The less common form comes from reduced sulphur compounds emitted from hot springs and deep ocean fumaroles; bacteria oxidize these molecules to acquire metabolic energy. This energy is derived from heat in the earth"s interior, which in turn is generated by fission decay of radioactive elements. The more common energy source is light energy, which is generated by thermonuclear fusion reactions in the sun. And, over 90% of energy consumed by society is derived from either recent photosynthetic products (wood, dung, peat, crop residues) or ancient photosynthetic products (oil, coal and natural gas).
