Foods energy from

As stated in section 5.1.1, some bacteria derive energy from food sources without the use of oxygen, whereas others are able to use this gas. The pathway of oxygen utilization itself is also a stepwise series of reactions and thus the overall picture emerges of cellular metabolism characterized by multistep reactions. 

Figure 2.2 Fat, or adipose, cells store extra energy from food. Adipose cells help insulate the body to keep it warm, cushion and protect the internal organs, and store extra energy for later use. When people consume more energy from food, the extra energy is stored as fat in adipose cells. Years ago, this stored energy could be used to avoid starvation in times of famine. Today, people never use this stored fat because famine does not exist in developed countries. These fat cells continue to accumulate and lead to weight gain and eventually to obesity.

Mitochondria Mitochondria are complex organelles that convert energy from food into a form that the cell can use. They have their own genetic material, separate from the DNA in the nucleus, and can make copies of themselves. 

Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Each cell contains hundreds to thousands of mitochondria, which are located in the fluid that surrounds the nucleus (the cytoplasm). 

Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Although most DNA is packaged in chromosomes within the nucleus, mitochondria also have a small amount of their own DNA (known as mitochondrial DNA or mtDNA). In some cases, inherited changes in mitochondrial DNA can cause problems with growth, development, and function of the body s systems. These mutations disrupt the mitochondria s ability to generate energy efficiently for the cell. 

The final stage in the extraction of energy from food is oxidative phosphorylation, in which the energy of NADH and FADHj is released via the electron transport chain (ETC) and used by an ATP synthase to produce ATP. This process requires O. ... 

State Enthalpies of Physical and Chemical Change Interlude—Energy from Food ... 

The energy budget is distributed somewhat differently in less active species. In red mullet and pickerel, which can be defined as moderately active fish, the energy from food is divided nearly equally between basal and active metabolism (30-35%) while feeding metabolism demands only 13-15%. However, the metabolic energy expenditure still exceeds that used for synthesis, although the latter is several times as great as in the most active fish. 

The cells of most organisms produce carbon dioxide, C02, during cellular respiration the process that releases energy from food. Plants, like the ones shown in Figure 3.4, synthesize their own food from carbon dioxide and water using the Sun s energy. 

In addition to obtaining energy from food, organisms must obtain the necessary nutrients to construct body tissues. For proper growth, most organisms require the following elements or essential nutrients (biogenetic elements) ... 

Oxidation—A biochemical process which is part of metabolism. It involves the steady but relatively slow release of energy from food molecules for cell activity. 

In the same way, the energy our bodies need to keep warm, move about, and build new tissue comes from a food reserve carbohydrates, chiefly in the form of starch. (We eat other animals, too, but ultimately the chain goes back to a carbo-hydrate-eater.) In the final analysis, we get energy from food just as we do from petroleum we oxidize it to carbon dioxide and water. 

Other cofactors involved in deriving energy from food include coenzyme A (derived from the vitamin pantothenate), thiamine pyrophosphate, and Upoic acid. 

The synthesis of fats is an important way an organism stores the energy from foods. The dehydration step in fatty acid biosynthesis is an example of an ElcB sequence in which the conjugate acid of the initial base serves to protonate the leaving group on departure. This second step is a general acid-catalyzed beta elimination (Section 7.4.3). 

ATP is an intermediate in the flow of energy from food molecules to the biosynthetic reactions of metabolism. 

DNP is a lipophilic molecule that binds reversibly with protons. It dissipates that proton gradient in mitochondria by transferring protons across the inner membrane. The uncoupling of electron transport from oxidative phosphorylation causes the energy from food to be dissipated as heat. DNP causes liver failure because of insufficient ATP synthesis in a metabolically demanding organ. 

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