Chapter 9: Cellular Respiration

substrate level phosphorylation

In substrate-level phosphorylation, the PO43- from a phosphorylated substrate is transferred to ADP to form ATP. Phosphorylases and kinases catalyse this process. This is what happens during glycolysis substrate level phosphorylation refers to the synthesis of ATP by reactions in which ADP is one of several substrates and ATP is one of several products of an enzyme catalyzed reaction.

oxidative phosphorylation

Oxidative phosphorylation is the process in which ATP is formed as a result of the transfer of electrons from NADH or FADH 2 to O 2 by a series of electron carriers. This process, which takes place in mitochondria, is the major source of ATP in aerobic organisms

redox reaction

Redox reactions, or oxidation-reduction reactions, primarily involve the transfer of electrons between two chemical species. The compound that loses an electron is said to be oxidized, the one that gains an electron is said to be reduced. Oxidation - involves the loss of electrons or hydrogen OR gain of oxygen OR increase in oxidation state Reduction - involves the gain of electrons or hydrogen OR loss of oxygen OR decrease in oxidation state

reduction

Reduction - involves the gain of electrons or hydrogen OR loss of oxygen OR decrease in oxidation state

oxidation

The combination of a substance with oxygen.

lactic acid fermentation

a type of fermentation muscle cells undergo; pyruvic acid + NADH --> lactic acid + NAD+ is known as ___ ___ fermentation Glycolysis is the chemical breakdown of glucose to lactic acid. This process makes energy available for cell activity in the form of a high-energy phosphate compound known as adenosine triphosphate ATP Lactic acid from glycolysis produces a feeling of tiredness; ie muscle fatigue

alcoholic fermentation

a type of fermentation; pyruvic acid + NADH --> alcohol + CO2 + NAD+ is known as ___ fermentation is a type of cellular Respiration which does not require oxygen (anaerobic respiration), and involves the breaking down of glucose to pyruvic acid and then finally ethanol. Alcoholic fermentation is identical to glycolysis except for the final step In alcoholic fermentation, pyruvic acid is broken down into ethanol and carbon dioxide.

NAD+

an electron carrier that accepts a pair of high-energy electrons; similar to NADP+ in photosynthesis Abbreviation for nicotinamide adenine dinucleotide, a coenzyme in NAD+ is an oxidizing agent - it accepts electrons from other molecules and becomes reduced. This reaction forms NADH, which can then be used as a reducing agent

cytochrome

any of several carrier molecules in the mitochondria of plant and animal cells, consisting of a protein and an iron-containing porphyrin ring and participating in the stepwise transfer of electrons in oxidation reactions: each cytochrome alternately accepts and releases an electron at a slightly lower energy level in the order designated b, c 1 , c, a, and a 3 .

chemosynthesis

is the biological conversion of one or more carbon molecules and nutrients into organic matter using the oxidation of inorganic molecules or methane as a source of energy, rather than sunlight, as in photosynthesis.

anaerobic

not requiring oxygen; because fermentation does not require oxygen, it is said to be ___ Anaerobic may be used to describe an organism, a cell, a process or a mechanism that can function without air (i.e. air to generally mean oxygen)

ATP synthase

plays a key role in biological energy metabolism. This enzyme interconverts two major "energy currencies" of a living cell: adenosine triphosphate (ATP) and transmembrane electrochemical proton potential difference. ATP synthase is found in bacteria, plants, and animals. In most organisms the primary function of the enzyme is ATP synthesis from adenosine diphosphate (ADP) and inorganic phosphate (Pi)

aerobic

requiring oxygen; the final steps of cellular respiration are ___ Aerobic respiration requires oxygen in order to generate ATP. Although carbohydrates, fats, and proteins can all be processed and consumed as reactants, it is the preferred method of pyruvate breakdown in glycolysis and requires that pyruvate enter the mitochondrion in order to be fully oxidized by the Krebs cycle.

electron transport chain

the ___ ___ ___ uses the high-energy electrons from the Krebs cycle to convert ADP into ATP An electron transport chain is a series of compounds that transfer electrons from electron donors to electron acceptors via redox reactions, and couples this electron transfer with the transfer of protons across a membrane.

acetyl-CoA

the compound formed when Coenzyme A joins the 2-carbon molecule Acetyl coenzyme A or acetyl-CoA is an important molecule in metabolism, used in many biochemical reactions. Its main function is to convey the carbon atoms within the acetyl group to the citric acid cycle to be oxidized for energy production.

facultative anaerobe

A facultative anaerobe is an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation or anaerobic respiration if oxygen is absent

proton-motive force

A proton-motive force is "energy that is generated by the transfer of protons or electrons across an energy-transducing membrane and can be used for chemical, osmotic or mechanical work." It can be "generated by a variety of phenomena uncluding the operation of an electron transport chain,

reducing agent

A reducing agent is an element or compound that loses an electron to another chemical species in a redox chemical reaction. Since the reducing agent is losing electrons, it is said to have been oxidized

Beta oxidation

Beta-oxidation is the process by which fatty acid molecules are broken down in the mitochondria to generate acetyl-coA, which enters the citric acid cycle, and NADH and FADH2, which are used by the electron transport chain.

citric acid cycle or krebs cycle

the compound formed when acetyl-CoA adds the 2-carbon acetyl group to a 4-carbon compound When oxygen is present, the pyruvate moves out of the cytosol in which glycolysis took place and crosses the membrane into the matrix of the mitochondria. There, before entering the citric acid cycle proper, the pyruvate undergoes a transition stage, in which the two pyruvates are converted into two acetyl-coenzyme A (acetyl-CoA), two carbon dioxide molecules, and two NADH. Then, during the series of eight reactions that make up the citric acid cycle, the two acetyl-coA molecules are oxidized, yielding two more molecules of carbon dioxide and 2 ATP. The carbon dioxide generated in these two processes is the carbon dioxide we exhale when we breathe.

glycolysis

the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid. Glycolysis is the metabolic pathway that converts glucose C6H12O6, into pyruvate, CH3COCOO− + H+. The free energy released in this process is used to form the high-energy compounds ATP and NADH.

cellular respiration

the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen The term cellular respiration refers to the biochemical pathway by which cells release energy from the chemical bonds of food molecules and provide that energy for the essential processes of life. All living cells must carry out cellular respiration. produces ATP and releases CO2 as waste

fermentation

the process that releases energy from food molecules by producing ATP in the absence of oxygen Fermentation occurs in fruits, bacteria, yeasts, fungi, as well as in mammalian muscle Fermentation differs from cellular respiration in a way that it uses organic compounds such as carbohydrates as (endogenous) electron acceptors instead of molecular oxygen (which is an exogenous electron acceptor in cellular respiration). However, compared with oxidative phosphorylation (of cellular respiration), fermentation produces less ATP.