Question

ATP molecules produced respectively by NADH $(H^{+})$ and $FADH_{2}$ during electron transport are
A. 3 and 2
B. 1 and 1
C. 2 and 3
D. 3 and 3

Answer 1

Hint: ATP or adenosine triphosphate is an organic energy rich compound molecule. It carries energy to fuel many biological processes in living cells such as muscle contraction, nerve impulse propagation, condensate dissolution, and different chemical synthesis.

Complete step by step answer: Adenosine triphosphate or ATP, is an energy-carrying bio-molecule that is present in the cells of all living things. ATP receives chemical energy which came from the breakdown of food molecules and supplies chemical energy to execute various cellular processes.
ATP has a nucleotide structure composed of three main components which are adenine, and the sugar i.e. ribose, and a chain of three phosphate groups that are attached to ribose. The phosphate tail of ATP acts as the main power supplier in the cell and the energy is stored in the bonds between the phosphates. When the bonds are broken, the energy gets released and this takes place through the addition of a water molecule. Generally, the outer phosphate bond is broken down to generate energy, and ATP is converted to adenosine diphosphate or ADP.
When the Krebs cycle and glycolysis take place, NADH and $FADH_{2}$ are generated and they are moved to the inner membrane and drop their electrons into the membrane. This release of electrons is called redox reaction and NADH converted into AD and $FADH_{2}$ converted into the FAD. The electrons pump the protons present through the inner membrane from the matrix to intermembrane space.
Each NADH pumps 3 protons and each $FADH_{2}$ pumps 2 protons. Due to this a concentration gradient of hydrogen atoms is found across the membrane. These hydrogen ions are moved back into the matrix by diffusion. Each proton that pumps by the electron produced one ATP. NADH makes 3 ATP and $FADH_{2}$ makes 2 ATP.
Therefore, the correct option is option A.

Note: ATP is the energy molecule of the cell. It provides energy during various processes like muscle contraction, nerve impulse propagation, etc. It consists of three main components; nitrogen base, sugar, and a phosphate group. Mainly this phosphate group produces energy. During the Krebs cycle and glycolysis, NADH and FADH2 are produced respectively 3 and 2 ATP due to the pumping of the proton by electrons.