Glycolysis occurs in the cytoplasm of cells, not in organelles, and occurs in all kinds of living organisms. Prokaryote cells use glycolysis and the first living cells most likely used glycolysis. Fermentation: During fermentation, the pyruvic acid produced during glycolysis is converted to either ethanol or lactic acid.
This continued use of pyruvic acid during fermentation permits glycolysis to continue with its associated production of ATP. Cellular Respiration: Respiration is the general process by which organisms oxidize organic molecules e.
In addition to the energy released, the products of the reaction are carbon dioxide and water. In eukaryotic cells, cellular respiration begins with the products of glycolysis being transported into the mitochondria. Figure 2. The energy required for extracting electrons from these molecules is much lower than that required for the hydrolysis of water. Photo-energy is more often used for nitrogenase activation, i. ATP reproduction Eq. The number of photons required for ATP reproduction by photosynthetic bacteria has not been theoretically elucidated, though an experimental number of 1.
A value of 1 has also been suggested In addition to ATP, nitrogenase-mediated reactions, require Fd as an electron carrier. Reaction mechanisms involved have not however been completely elucidated 10, The reducing potential, created in the RC of purple, non-sulfur photosynthetic bacteria such as R. Such bacteria would be incapable of directly reducing Fd, which has an oxidizing and reducing potential of approximately mV.
ATP may however be capable of reducing Fd. Assuming that one ATP molecule is used for reducing one Fd molecule, at least six ATP molecules are needed for the production of one hydrogen molecule, resulting in a net requirement for nine photons.
Energy is also required for the decomposition of organic substances Equation This energy is however, much lower 8. It is unlikely that improvements can be made in the photo-energy conversion efficiencies of nitrogenases. On the other hand, hydrogenases catalyze hydrogen-producing reactions without ATP requirements Eq. Hydrogenase-catalyzed reactions are reversible, and are either biased in favour of hydrogen production or hydrogen uptake.
Hydrogenases in Clostridium and other bacteria work primarily to produce hydrogen, while hydrogenases in photosynthetic bacteria work toward hydrogen uptake.
Hydrogen-producing efficiency is known to be higher in hydrogenase-deplete strains of photosynthetic bacteria. Hydrogen-producing hydrogenases, such as those which occur in species such as Clostridium are required for hydrogen production.
However, problems such as the necessity for complex control are encountered with the use of hydrogenases. Leaves and leaf structure Plants are the only photosynthetic organisms to have leaves and not all plants have leaves. A leaf may be viewed as a solar collector crammed full of photosynthetic cells.
The raw materials of photosynthesis, water and carbon dioxide, enter the cells of the leaf, and the products of photosynthesis, sugar and oxygen, leave the leaf.
Water enters the root and is transported up to the leaves through specialized plant cells known as xylem vessels. Land plants must guard against drying out and so have evolved specialized structures known as stomata to allow gas to enter and leave the leaf. Carbon dioxide cannot pass through the protective waxy layer covering the leaf cuticle , but it can enter the leaf through the stoma the singular of stomata , flanked by two guard cells.
Likewise, oxygen produced during photosynthesis can only pass out of the leaf through the opened stomata. Unfortunately for the plant, while these gases are moving between the inside and outside of the leaf, a great deal of water is also lost. Cottonwood trees, for example, will lose gallons about dm3 of water per hour during hot desert days.
The structure of the chloroplast and photosynthetic membranes The thylakoid is the structural unit of photosynthesis. Only eukaryotes have chloroplasts with a surrounding membrane. Thylakoids are stacked like pancakes in stacks known collectively as grana.
The areas between grana are referred to as stroma.
Hydrogen-producing hydrogenases, such as those which occur in species such as Clostridium are required for hydrogen production. O and K. A key factor in determining the commercial applicability of hydrogen production processes, is the rate at which hydrogen is produced. Ku, S. Hall, D. The mitochondria use the energy released in this oxidation in order to synthesize ATP.
Miyake, J. Accessory pigments absorb energy that chlorophyll a does not absorb. Energy is also required for the decomposition of organic substances Equation Random House. A key factor in determining the commercial applicability of hydrogen production processes, is the rate at which hydrogen is produced. The reducing potential, created in the RC of purple, non-sulfur photosynthetic bacteria such as R.
On the other hand, hydrogenases catalyze hydrogen-producing reactions without ATP requirements Eq. Miyake, J. In eukaryotic cells, cellular respiration begins with the products of glycolysis being transported into the mitochondria. Only eukaryotes have chloroplasts with a surrounding membrane. Hydrogen-producing hydrogenases, such as those which occur in species such as Clostridium are required for hydrogen production. Hydrogen-producing efficiency is known to be higher in hydrogenase-deplete strains of photosynthetic bacteria.
Function Photosynthesis uses light energy to convert carbon dioxide and water into glucose and oxygen gas. All photosynthetic organisms have chlorophyll a. Clayton, R. ATP reproduction Eq. CO2 and H2O are end products of these reactions. Ku, S.
Chlorophyll - click on image to open All chlorophylls have: a lipid-soluble hydrocarbon tail C20H39 - a flat hydrophilic head with a magnesium ion at its centre; different chlorophylls have different side-groups on the head The tail and head are linked by an ester bond. Miyake, J and Kawamura, S.