Anabolic and Catabolic ReactionsCatabolism refers to metabolic reactions that break down larger molecules to smaller ones. Catabolism usually involves atp hydrolysis anabolic. Anabolism refers to metabolic reactions that synthesize larger molecules from smaller ones. Anabolism usually involves reduction. Catabolic reactions release energy and anabolic reactions require energy.
Catabolism refers to metabolic reactions that break down larger molecules to smaller ones. Catabolism usually involves oxidation. Anabolism refers to metabolic reactions that synthesize larger molecules from smaller ones. Anabolism usually involves reduction.
Catabolic reactions release energy and anabolic reactions require energy. The oxidation state of a molecule is related to its available energy. The higher the oxidation state of a molecule, the less energy that can be obtained from it.
Thus, glucose, which has a higher oxidation state than fatty acids, provides less energy to cells than fatty acids. The first two are used to accept electrons in redox reactions, whereas NADPH is used mostly in anabolic reactions.
Activated carriers contain a high energy between themselves such as CoA and the molecule they are carrying acetyl group. The high energy of their bond is used to make possible the reaction where the molecule being carried is donated to a larger molecule. There are six classes of reactions catalyzed by enzymes. Glycolysis, the breakdown of glucose, is a catabolic pathway involving oxidation and yields ATP energy. There are 10 reactions in glycolysis.
Students should know structures of fructose and glucose compounds, all enzyme names discussed in class, all molecule names discussed in class, and reactions I described in class where the Delta G zero prime is strongly positive, or strongly negative. Note that glycolysis has three phases - an energy investment phase, a molecular rearrangement phase, and an energy realization phase where ATP is made. In reaction 1 of glycolysis, hexokinase catalyzes transfer of phosphate to glucose from ATP, forming G6P.
Thus, this step uses ATP, which provides the energy necessary for the reaction to proceed. It is an example of an energy-coupled reaction and the Delta G zero prime is strongly negative, thanks to the ATP hydrolysis. Hexokinase changes shape as it binds to glucose. This property is consistent with that of an induced fit of an enzyme in the process of catalysis.
Reaction 2 of glycolysis is catalyzed by phosphoglucoisomerase. In it, G6P is converted to F6P. The Delta G zero prime for the reaction is close to zero. Note than a linear intermediate is formed in the process. Reaction 3 is the primary regulatory reaction of glycolysis. It is catalyzed by phosphofructokinase PFK.
Note that this reaction also requires ATP. PFK is the most important regulatory enzyme for glycolysis. The molecule made in the process, F1,6BP, is a high energy molecule and the energy in the molecule is needed in the next reaction.
The reaction is another example of an energy-coupled reaction and the Delta G zero prime is strongly negative, thanks to the ATP hydrolysis. Reaction 4 is catalyzed by aldolase. It has a strongly positive Delta G zero prime. In the cell, however, the reaction is pulled by reactions ahead of it which remove products and pushed by reactions behind it which increase amounts of reactants , making the Delta G favorable negative.