Respiration cellular

The ready reversibility of this reaction is essential to the role that qumones play in cellular respiration the process by which an organism uses molecular oxygen to convert Its food to carbon dioxide water and energy Electrons are not transferred directly from the substrate molecule to oxygen but instead are transferred by way of an electron trans port chain involving a succession of oxidation-reduction reactions A key component of this electron transport chain is the substance known as ubiquinone or coenzyme Q... 

Coenzyme Q (Section 24.14) Naturally occurring group of related quinones involved in the chemistry of cellular respiration. Also known as ubiquinone. 

Prokaryotic cells have only a single membrane, the plasma membrane or cell membrane. Because they have no other membranes, prokaryotic cells contain no nucleus or organelles. Nevertheless, they possess a distinct nuclear area where a single circular chromosome is localized, and some have an internal membranous structure called a mesosome that is derived from and continuous with the cell membrane. Reactions of cellular respiration are localized on these membranes. In photosynthetic prokaryotes such as the cyanobacteria,... 

The fixation of carbon dioxide to form hexose, the dark reactions of photosynthesis, requires considerable energy. The overall stoichiometry of this process (Eq. 22.3) involves 12 NADPH and 18 ATP. To generate 12 equivalents of NADPH necessitates the consumption of 48 Einsteins of light, minimally 170 kj each. However, if the preceding ratio of l ATP per NADPH were correct, insufficient ATP for COg fixation would be produced. Six additional Einsteins would provide the necessary two additional ATP. Prom 54 Einsteins, or 9180 kJ, one mole of hexose would be synthesized. The standard free energy change, AG°, for hexose formation from carbon dioxide and water (the exact reverse of cellular respiration) is +2870 kj/mol. 

In both plant (e.g. [57]) and animal (e.g. [86]) cell systems, cellular respiration has been shown to be a more sensitive indicator of system response to hydro-dynamic stress than membrane integrity, suggesting that intracellular enzymes and/or organelles may be affected at stress levels lower than those required to cause membrane damage. 

Besides, potentiometric sensors with ion-selective ionophores in modified poly(vinyl chloride) (PVC) have been used to detect analytes from human serum [128], Cellular respiration and acidification due to the activity of the cells has been measured with CMOS ISFETS [129], Some potentiometric methods employ gas-sensing electrodes for NH3 (for deaminase reactions) and C02 (for decarboxylase reactions). Ion-selective electrodes have also been used to quantitate penicillin, since the penicillinase reaction may be mediated with I or GST. 

M. Lehmann, W. Baumann, M. Brischwein, H.J. Gahle, I. Freund, R. Ehret, S. Drechsler, H. Palzer, M. Kleintges, U. Sieben, and B. Wolf, Simultaneous measurement of cellular respiration and acidification with a single CMOS ISFET. Biosens. Bioelectron. 16, 195-203 (2001). 

The production of NO within or around neurons, can impart irreversible adverse affects on mitochondrial 02-dependent cellular respiration [21, 333, 334]. Degenerative diseases that involve NO correspond to toxicity that parallels the loss of mito-... 

HCN is among the most rapidly acting of all known poisons. Absorption occurs by all routes the mechanism of action is inhibition of cellular respiration. The respiratory, central nervous, and cardiovascular systems are the primary targets of an acute exposure. Information on human exposures was limited to exposures to high concentrations for short time intervals, poorly documented accidental exposures, and chronic occupational exposures. 

Mitochondria are found in the cell body and all processes of the neuron. They possess a double membrane and their own DNA and they play a role in cellular respiration and energy synthesis. Mitochondria contain enzymes essential for energy production in the form of adenosine triphosphate (ATP). 

Carbohydrates are found in foods such as bread, pasta, potatoes, and fruits. They are the primary source of energy for the body. In a process called cellular respiration, carbohydrates combine with inhaled oxygen and are oxidized to produce carhon dioxide and water, plus energy. As shown in Figure 2.18, carhon dioxide and water vapour from cellular respiration are expelled in your hreath. 

Quinones are widespread in natnre (Thomson, 1971) and have a variety of functions in the life cycles of most kinds of living organisms. These diketones are fonnd in higher plants, fungi, bacteria, and throughout the animal kingdom, and they play a central role in many biosynthetic processes that involve electron transport, such as cellular respiration (nbiqninone) and photosynthesis (plastoqninone). Vitamin K is an important factor in blood... 

Mitochondria, which are cytoplasmic organelles involved in cellular respiration, have their own chromosome, which contains 16,569 DNA base pairs (bp) arranged in a drcalar molecule. This DNA encodes 13 proteins that are subunits of complexes in the electron transport and oxidative phosphorylation processes (see Section 1, Chapter 13). In addition, mitochondrial DNA encodes 22 transfer RNAs and two ribosomal RNAs. 

In the rabbit eye, a drop of the liquid caused superficial injury. The liquid on the belly of a rabbit caused a faint erythema of short duration. The toxic effects of acetonitrile are attributed to the metabolic release of cyanide via hepatic metabolism cyanide in turn acts by inhibiting cytochrome oxidase and thus impairs cellular respiration. Evidence of the cyanide effect is supported by the reported effectiveness of specific cyanide antidotes in acetonitrile poisonings. ... 

Cyanide ion exerts an inhibitory action on certain metabolic enzyme systems, most notably cytochrome oxidase, the enzyme involved in the ultimate transfer of electrons to molecular oxygen. Because cytochrome oxidase is present in practically all cells that function under aerobic conditions, and because the cyanide ion diffuses easily to all parts of the body, cyanide quickly halts practically all cellular respiration. The venous blood of a patient dying of cyanide is bright red and resembles arterial blood because the tissues have not been able to utilize the oxygen brought to them. Cyanide intoxication produces lactic acidosis, the result of an increased rate of glycolysis and production of lactic acid. ... 

At the cellular level, rotenone inhibits cellular respiration by blocking electron transport between flavoprotein and ubiquinone. It also inhibits spindle microtubule assembly. ... 

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