Question

explain what happens in (glycolysis, transition step, krebs cycle, light reactions, Calvin cycle) What us oxidized? What is reduced? Inputs? Outputs?

Answer 1

1.GLYCOLYSIS:The process takes place in the cytoplasm.The process creates 2ATP's and 2NADP's,but in the end uses these products glucose(6c)is broken down into 2PGALS(phosphoglyceraldehide -3 carbon molecules)This process takes 2ATPmolecules,3PGAL's(3C) are convereted into 2 pyruvates and this creates 4ATPS AND 2NADPH'S.The net ATPproduction of glycolysis is 2ATP'S

2.CALVIN CYCLE:

In plants, carbon dioxide (\text{CO}_2CO2​start text, C, O, end text, start subscript, end subscript) enters the interior of a leaf via pores called stomata and diffuses into the stroma of the chloroplast—the site of the Calvin cycle reactions, where sugar is synthesized. These reactions are also called the light-independent reactions because they are not directly driven by light.

In the Calvin cycle, carbon atoms from \text {CO}_2CO2​start text, C, O, end text, start subscript, , end subscript are fixed (incorporated into organic molecules) and used to build three-carbon sugars. This process is fueled by, and dependent on, ATP and NADPH from the light reactions. Unlike the light reactions, which take place in the thylakoid membrane, the reactions of the Calvin cycle take place in the stroma (the inner space of chloroplast)

KREBS CYCLE: The Krebs cycle, also known as the citric acid cycle or the tricarboxylic acid cycle, is one of the most important reaction sequences in biochemistry. Not only is this series of reactions responsible for most of the energy needs in complex organisms, the molecules that are produced in these reactions can be used as building blocks for a large number of important processes, including the synthesis of fatty acids, steroids, cholesterol, amino acids for building proteins, and the purines and pyrimidines used in the synthesis of DNA. Fuel for the Krebs cycle comes from lipids (fats) and carbohydrates, which both produce the molecule acetyl coenzyme-A (acetyl-CoA). This acetyl-CoA reacts in the first step of the eight step sequence of reactions that comprise the Krebs cycle, all of which occur inside mitochondria of eukaryotic cells. While the Krebs cycle does produce carbon dioxide, this cycle does not produce significant chemical energy in the form of adenosine triphosphate (ATP) directly, and this reaction sequence does not require any oxygen. Instead, this cycle produces NADH and FADH2, which feed into the respiratory cycle, also located inside of the mitochondria.

TRANSISTION CYCLE:

Formation of Acetyl-CoA through the Transition Reaction

The transition reaction connects glycolysis to the citric acid (Krebs) cycle. Through a process called oxidative decarboxylation, the transition reaction converts the two molecules of the 3-carbon pyruvate from glycolysis (and other pathways) into two molecules of the 2-carbon molecule acetyl Coenzyme A (acetyl-CoA) and 2 molecules of carbon dioxide. First, a carboxyl group of each pyruvate is removed as carbon dioxide and then the remaining acetyl group combines with coenzyme A (CoA) to form acetyl-CoA.

The Transition Reaction between Glycolysis and the Citric Acid Cycle. Before the pyruvates from glycolysis can enter the citric acid cycle, they must undergo a transition reaction. The 3-carbon pyruvate is converted into a 2-carbon acetyl group with a carboxyl being removed as CO2. The acetyl group is attached to coenzyme A to form acetyl coenzyme A (acetyl-CoA), a key precursor metabolite. As the two acetyl groups become oxidized to acetyl-CoA, two molecules of NAD+ are reduced to 2NADH + 2H+.