In what stage of cellular respiration is most of the carbon dioxide produced?
C. citric-acid cycle
D. electron transport chain
Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga.
Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus.
Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
Respiration occurs in three stages. The first stage is glycolysis, which is a series of enzyme-controlled reactions that degrades glucose (a 6-carbon molecule) to pyruvate (a 3-carbon molecule) which is further oxidized to acetylcoenzyme A (acetyl CoA). Amino acids and fatty acids may also be oxidized to acetyl CoA as well as glucose.
In the second stage, acetyl CoA enters the citric acid (Krebs) cycle, where it is degraded to yield energy-rich hydrogen atoms which reduce the oxidized form of the coenzyme nicotinamide adenine dinucleotide (NAD+) to NADH, and reduce the coenzyme flavin adenine dinucleotide (FAD) to FADH2. (Reduction is the addition of electrons to a molecule, or the gain of hydrogen atoms, while oxidation is the loss of electrons or the addition of oxygen to a molecule.) Also in the second stage of cellular respiration, the carbon atoms of the intermediate metabolic products in the Krebs cycle are converted to carbon dioxide.
The third stage of cellular respiration occurs when the energy-rich hydrogen atoms are separated into protons [H+] and energy-rich electrons in the electron transport chain. At the beginning of the electron transport chain, the energy-rich hydrogen on NADH is removed from NADH, producing the oxidized coenzyme, NAD+ and a proton (H+) and two electrons (e-). The electrons are transferred along a chain of more than 15 different electron carrier molecules (known as the electron transport chain). These proteins are grouped into three large respiratory enzyme complexes, each of which contains proteins that span the mitochondrial membrane, securing the complexes into the inner membrane. Furthermore, each complex in the chain has a greater affinity for electrons than the complex before it. This increasing affinity drives the electrons down the chain until they are transferred all the way to the end where they meet the oxygen molecule, which has the greatest affinity of all for the electrons. The oxygen thus becomes reduced to H2O in the presence of hydrogen ions (protons), which were originally obtained from nutrient molecules through the process of oxidation.
During electron transport, much of the energy represented by the electrons is conserved during a process called oxidative phosphorylation. This process uses the energy of the electrons to phosphorylate (add a phosphate group) adenosine diphosphate (ADP), to form the energy-rich molecule ATP.