Energy from human activity

Such sources caused by human activity include industry, energy production, transport, residential heating and waste incineration. These sources give rise to different contributions to the total emissions resulting from human activity, depending on the structure of the economy. Table 5.7 presents the relative percentage contributions to the pollution from the human activity. 

The processes of electron transport and oxidative phosphorylation are membrane-associated. Bacteria are the simplest life form, and bacterial cells typically consist of a single cellular compartment surrounded by a plasma membrane and a more rigid cell wall. In such a system, the conversion of energy from NADH and [FADHg] to the energy of ATP via electron transport and oxidative phosphorylation is carried out at (and across) the plasma membrane. In eukaryotic cells, electron transport and oxidative phosphorylation are localized in mitochondria, which are also the sites of TCA cycle activity and (as we shall see in Chapter 24) fatty acid oxidation. Mammalian cells contain from 800 to 2500 mitochondria other types of cells may have as few as one or two or as many as half a million mitochondria. Human erythrocytes, whose purpose is simply to transport oxygen to tissues, contain no mitochondria at all. The typical mitochondrion is about 0.5 0.3 microns in diameter and from 0.5 micron to several microns long its overall shape is sensitive to metabolic conditions in the cell. 

Chemical energy fuels all human activity, whether it be work or play (Figure 6-81. In any physical activity, a person does work to accomplish movement, and the energy for this work comes from the chemical energy stored In food. Our explores human energy requirements. 

All physical human activities involve doing thermodynamic work, which the body supplies from the chemical energy stored in foods. 

Dinitrophenol is a member of the aromatic family of pesticides, many of which exhibit insecticide and fungicide activity. DNP is considered to be highly toxic to humans, with a lethal oral dose of 14 to 43mg/kg. Environmental exposure to DNP occurs primarily from pesticide runoff to water. DNP is used as a pesticide, wood preservative, and in the manufacture of dyes. DNP is an uncoupler, or has the ability to separate the flow of electrons and the pumping of ions for ATP synthesis. This means that the energy from electron transfer cannot be used for ATP synthesis [75,77]. The mechanism of action of DNP is believed to inhibit the formation of ATP by uncoupling oxidative phosphorylation. 

Genchi et al. (2000) showed that heat dissipation from traffic, air conditioning, and other human activities, during a warm day in Tokyo, adds up to a heat production of 140 W m-2 in Tokyo with a resulting air temperature increase of about 3 °C. A similar estimation for Stockholm results in 70 W m-2. The Swedish energy consumption, mainly based on fossil fuel and nuclear power, corresponds to a national heat generation of 0.16 W m-2 though the country is sparsely populated (20 person km-2). 

Although much of the preceding discussion involved the synthesis of new molecules by organic and inorganic chemists, there is another area of chemistry in which such creation is important—the synthesis of new atoms. The periodic table lists elements that have been discovered and isolated from nature, but a few have been created by human activity. Collision of atomic particles with the nuclei of existing atoms is the normal source of radioactive isotopes and of some of the very heavy elements at the bottom of the periodic table. Indeed nuclear chemists and physicists have created some of the most important elements that are used for nuclear energy and nuclear weapons, plutonium in particular. 

Radioactivity is a form of energy emitted by radioactive elements (radioisotopes or radionuclides). Radionuclides can present a health threat to humans and marine organisms because of the ionizing ability of the emitted radiation. The major pathway by which marine organisms and humans are exposed to radionuclides comes from consumption of fish and shellfish due to bioaccumulation of °Po and °Pb. Most of the °Po and Pb in the ocean is natural, but, human activities have increased their inputs to the coastal ocean. 

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