How many electrons must move down the Electron Transport Chain before energy is made?(1 point)
Responses
5
5
2
2
3
3
4
4
Which 3-carbon molecule is one of the final products of glycolysis?(1 point)
Responses
NAD+
NAD+
oxaloacetic acid
oxaloacetic acid
ADP
ADP
pyruvic acid
pyruvic acid
To determine the number of electrons that must move down the Electron Transport Chain before energy is made, we need to understand the process of electron transport in cellular respiration.
During cellular respiration, the Electron Transport Chain is the final stage of the process where the majority of ATP (energy) is generated. In this chain, electrons are passed from one molecule to another through a series of protein complexes, creating a flow of electrons. This flow of electrons provides the energy required to pump protons across the inner mitochondrial membrane, creating an electrochemical gradient.
For every NADH molecule (the reduced form of nicotinamide adenine dinucleotide) that enters the Electron Transport Chain, three electron transfers occur, resulting in the production of 3 ATP molecules. On the other hand, for every FADH2 molecule (the reduced form of flavin adenine dinucleotide), only two electron transfers occur, producing 2 ATP molecules.
Considering this information, if we assume a balanced number of NADH and FADH2 molecules, we can calculate the total number of electrons moved down the Electron Transport Chain to produce energy.
In this case, 5 is the correct answer. By multiplying 3 (the number of electron transfers for each NADH) by 5 (the number of NADH molecules), we get 15 electron transfers. Additionally, by multiplying 2 (the number of electron transfers for each FADH2) by 2 (the number of FADH2 molecules), we get 4 electron transfers.
Therefore, in total, 19 electron transfers (15 from NADH and 4 from FADH2) occur before energy is produced in the Electron Transport Chain.