Question

Which of the following processes produces ATP, NADP and $FADH_2$ from pyruvate ?
A. Krebs Cycle
B. Electron Transport Chain
C. Fermentation
D. Glycolysis
E. Calvin cycle

Answer 1

Two molecules of acetyl -CoA are produced from each glucose molecule so two turns of krebs cycle are required which yield for $CO_2$, 6 NADH 2 $FADH_2$ and 2ATPs. In this process , two molecules of $CO_2$ are released and oxaloacetate is recycled. Energy is stored in ATP and other high energy compounds like NADH and $FADH_2$.

Complete answer:
The tricarboxylic acid cycle, commonly known as the Krebs or citric acid cycle, is the primary source of energy for cells and is an essential component of aerobic respiration. The cycle converts the available chemical energy of acetyl coenzyme A (acetyl CoA) into nicotinamide adenine dinucleotide reducing power (NADH).
The electron transport chain is a network of electron transporters located in the inner mitochondrial membrane that transports electrons from NADH and $FADH_2$ to molten oxygen. Protons are pumped from the mitochondrial matrix to the intermembrane gap and oxygen is reduced to create water as a result of this process.
Fermentation is a metabolic process that uses enzymes to cause chemical changes in organic substrates. It is described as the extraction of energy from carbohydrates in the absence of oxygen in biochemistry.
One molecule of glucose is transformed into two molecules of pyruvate, two hydrogen ions, and two molecules of water during glycolysis. The 'high energy' intermediary molecules of ATP and NADH are synthesised during this process.
The calvin cycle is a process that plants and algae use to turn $CO_2$. Plants depend on the calvin cycle for energy and food.
Krebs cycle produces ATP, NADP and $FADH_2$ from pyruvate.
Hence option A. is the correct answer.

Note:
The krebs cycle is a series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetate derived from carbohydrate, fats and proteins into $CO_2$ . The cycle is also central to biosynthetic reactions where the intermediates produced are required to make other molecules , such as amino acid , nucleotide base and cholesterol.