Question 14
The Krebs cycle produces electron carrier molecules. Where do these carrier molecules deliver the electrons produced in the Krebs cycle?
a
the electron transport chain
b
glycolysis
c
lactic acid fermentation
d
alcohol fermentation
a. the electron transport chain
The correct answer is a. The electron carrier molecules produced in the Krebs cycle, such as NADH and FADH2, deliver the electrons to the electron transport chain.
The correct answer is option a: the electron transport chain.
To understand why the electron carrier molecules produced in the Krebs cycle deliver the electrons to the electron transport chain, we first need to understand the Krebs cycle and the electron transport chain.
The Krebs cycle, also known as the citric acid cycle or the tricarboxylic acid cycle, is a series of chemical reactions that occur in the mitochondria of cells. Its primary function is to generate high-energy molecules, such as ATP (adenosine triphosphate), which is the main energy source for cellular activities.
During the Krebs cycle, a series of chemical reactions take place that involve the breakdown of acetyl-CoA, which is derived from the breakdown of carbohydrates, fats, and proteins. As a result of these reactions, several high-energy molecules, including NADH (Nicotinamide adenine dinucleotide) and FADH2 (Flavin adenine dinucleotide), are produced as electron carrier molecules.
Now, let's move on to the electron transport chain. This process takes the high-energy electrons carried by NADH and FADH2 from the Krebs cycle and uses them to create a gradient of protons (H+) across the inner mitochondrial membrane. This proton gradient is then used to generate ATP, the energy currency of the cell.
In summary, the electron carrier molecules (NADH and FADH2) produced in the Krebs cycle deliver the electrons to the electron transport chain, where they are used to create a proton gradient and generate ATP. Therefore, the correct answer is option a: the electron transport chain.