Question

In the citric acid cycle (also known as the Krebs cycle), acetyl CoA is completely oxidized. From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of the citric acid cycle.

Drag each compound to the appropriate bin. If a compound is not involved in the citric acid cycle, drag it to the "not input or output" bin. (Note that not all of the inputs and outputs of the citric acid cycle are included.)
a. Net input:
Acetyl CoA
NAD⁺
ADP
b. Net output:
NADH
CO₂
ATP
Coenzyme A
c. Not input ot output:
Glucose
O₂
Pyruvate

Answer 1

The citric acid cycle involves the complete oxidation of acetyl CoA, with acetyl CoA, NAD+, and ADP entering the cycle as net inputs and NADH, CO2, ATP, and regenerated Coenzyme A as outputs. Glucose, O2, and pyruvate are not directly involved as inputs or outputs in this cycle.

Step-by-step explanation:

The citric acid cycle (also known as the Krebs cycle or TCA cycle) is a crucial part of cellular respiration where acetyl CoA is fully oxidized. During this process, acetyl CoA combines with a four-carbon molecule called oxaloacetate to form citric acid. This is followed by a series of reactions, leading to the production of ATP and the reduction of electron carriers.

During each turn of the cycle, for each acetyl group fed into the cycle, citric acid cycle processes result in the production of three NADH, one FADH₂, and one ATP (or GTP, depending on the cell type) molecules, by processes including substrate-level phosphorylation. In the presence of oxygen, acetyl CoA's entrance into the cycle leads to the ultimate production of CO₂ and H₂O, while electron carriers such as NAD⁺ are reduced to NADH. These molecules can then be used in the electron transport chain to generate more ATP.