4. In the Krebs cycle (or citric acid cycle), starting with citrate, what happens?
a. Organic compounds become more reduced and CO2 is produced
b. Organic compounds become more oxidized and CO2 is produced
c. Some organic compounds become reduced and electron carriers become reduced.
d. Some organic compounds are oxidized and electron carriers become oxidized and CO2 is
produced
is it b?
Yes, the correct answer is b. In the Krebs cycle, also known as the citric acid cycle, organic compounds become more oxidized and CO2 is produced.
To arrive at this answer, it is important to understand the key events that occur in the Krebs cycle. The Krebs cycle is a series of chemical reactions that take place in the mitochondria of cells. It is a fundamental part of cellular respiration, which is the process by which cells convert glucose into energy (ATP) to fuel various cellular activities.
The Krebs cycle starts with the compound citrate, which is derived from the breakdown of glucose. During the cycle, citrate undergoes a series of chemical transformations and reactions. In each step, certain organic compounds are oxidized, meaning they lose electrons, while other compounds are reduced, meaning they gain electrons.
As the cycle progresses, high-energy electrons are released and captured by electron carriers such as NAD+ (nicotinamide adenine dinucleotide). These electron carriers become reduced, meaning they gain electrons and become NADH. The reduced electron carriers, including NADH, will then go on to participate in the electron transport chain, where further energy will be generated.
Furthermore, as the organic molecules in the Krebs cycle become oxidized, carbon atoms are removed in the form of carbon dioxide (CO2). This is one of the key contributions of the cycle, as it completes the breakdown of glucose and releases CO2 as a waste product.
Therefore, option b, which states that organic compounds become more oxidized and CO2 is produced, is the correct answer.