Question

1. according to model 2, what happens to pyruvic acid during the krebs cycle?
2. according to model 2, where does the change identified in the previous question occur?
3. note the number of atoms of carbon in pyruvic acid and explain why three molecules of carbon dioxide are produced.

Explanation:

8.

Step1: Analyze the model

In the model, pyruvic acid (3 - carbon molecule) is transformed.

Step2: Identify the change

Pyruvic acid is broken down. Carbon atoms are removed and released as carbon dioxide. Also, \(NAD^{+}\) is reduced to \(NADH\) and \(FAD\) is reduced to \(FADH_{2}\), and some \(ADP\) is converted to \(ATP\).

Step1: Locate the site in the model

In the model, the relevant part for the change of pyruvic acid (from question 8) is labeled.

Step2: Name the location

The change occurs in the mitochondrial matrix.

Step1: Count carbon atoms in pyruvic acid

Pyruvic acid (\(C_{3}H_{4}O_{3}\)) has 3 carbon atoms.

Step2: Apply the law of conservation of mass

In a chemical reaction (Krebs cycle), mass (and thus the number of atoms of each element) is conserved. Each carbon dioxide (\(CO_{2}\)) molecule has 1 carbon atom.

Answer:

Pyruvic acid is broken down. Carbon atoms are removed and released as carbon dioxide. \(NAD^{+}\) is reduced to \(NADH\), \(FAD\) is reduced to \(FADH_{2}\), and some \(ADP\) is converted to \(ATP\).

9.