In this part, you will know how rubisco is activated in the light and inactivated in the dark. Know how Mg 2+, pH and light are related to it activation; know how Ribulose-1,5-bisphosphate acts as a substrate and an inhibitor of rubisco; understand the oxygenase/carboxylase activities of rubisco. Know what are the products of the two reactions;...
In this chapter, you will learn to: Know that photosynthesis is broken up into two parts: Light rxns and carbon fixation, know the names of the major components of the chloroplast and the functions and properties of these components, know how light energy is converted to chemical energy, understand how a photon can excite an electron to a high energy orbital, know what happens when the electron returns to ground state,...
Why did I decide to write this book? As an undergraduate student I could not
make up my mind whether I wanted to be a zoologist or a botanist, so I decided to
adopt ecology, in its broadest sense, as my area of interest. This led me to think
about interactions among organisms and to try to look at ecosystems from a
holistic, rather than from an autecological, point of view. As someone with little
formal training in mycology, my interest in fungi started during my doctoral
research, especially when attending university-wide lectures by C. T. Ingold,
given at the University of London.
Photosynthesis is the primary source of energy for all life forms (except chemolithotrophic prokaryotes). Much of the energy of photosynthesis is used to drive the synthesis of organic molecules from atmospheric CO2. How is solar energy captured and transformed into metabolically useful chemical energy? How is the chemical energy produced by photosynthesis used to create organic molecules from carbon dioxide?
Phototrophic green bacteria, phototrophic purple
bacteria, and heliobacteria are three groups of bacteria that use anoxygenic photosynthesis.
Anoxygenic phototrophs have photosynthetic pigments called bacteriochlorophylls.
Bacteriochlorophyll a and b have maxima wavelength absorption at 775 nm and 790 nm,
respectively in ether. Unlike oxygenic phototrophs, anoxygenic photosynthesis only
functions using a single photosystem. This restricts them to cyclic electron flow only, and
they are therefore unable to produce O2 from the oxidization of H2O.
Ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO) is the key
enzyme of the Calvin cycle, catalyzing the fixation of inorganic carbon
dioxide to organic sugars. Unlike most enzymes, RuBisCO is extremely
slow, substrate unspecific, and catalyzes undesired side-reactions, which are
considered to be responsible for the slow deactivation observed in vitro,
a phenomenon known as fallover.