The Krebs cycle produces electron carrier molecules. Where do these carrier molecules deliver the electrons produced in the Krebs cycle?
a
glycolysis
b
the electron transport chain
c
lactic acid fermentation
d
alcohol fermentation
b) the electron transport chain
The electron carrier molecules produced in the Krebs cycle deliver the electrons to the electron transport chain.
The correct answer is b) the electron transport chain.
To understand why, let's go through the steps of the Krebs cycle and how it connects to the electron transport chain. The Krebs cycle, also known as the citric acid cycle or TCA cycle, occurs in the mitochondria of cells and plays a crucial role in cellular respiration.
During the Krebs cycle, a series of chemical reactions takes place, ultimately producing high-energy electron carrier molecules such as NADH and FADH2. These molecules are created when certain enzymes in the Krebs cycle strip off electrons from molecules involved in the cycle.
After their formation in the Krebs cycle, these electron carrier molecules, particularly NADH and FADH2, transport the electrons they have acquired to the next step in cellular respiration, which is the electron transport chain.
The electron transport chain is a series of proteins located within the inner mitochondrial membrane. It is responsible for transferring the electrons extracted from the Krebs cycle to generate ATP, the primary energy currency of cells.
As the electrons pass along the electron transport chain, a process known as oxidative phosphorylation occurs. This process leads to the pumping of protons across the inner mitochondrial membrane, creating an electrochemical gradient. Ultimately, this gradient drives the synthesis of ATP from ADP and inorganic phosphate.
So, in summary, the electron carrier molecules produced in the Krebs cycle, such as NADH and FADH2, deliver the electrons they carry to the electron transport chain to generate ATP. Hence, the correct answer to the question is b) the electron transport chain.