Ch.18 Metabolic Pathways and ATP Production

Timberlake - Chemistry: An Introduction to General, Organic, and Biological Chemistry 13th Edition

Timberlake13th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9780134421353Not the one you use?Change textbook

Timberlake 13th Edition

Ch.18 Metabolic Pathways and ATP Production

Problem 42d

Chapter 18, Problem 42d

Refer to the diagram of the citric acid cycle in Figure 18.13 to answer each of the following:
d. In which reactions are secondary alcohols oxidized?

Verified step by step guidance

Identify the secondary alcohols in the citric acid cycle. Secondary alcohols are characterized by the hydroxyl group (-OH) attached to a carbon atom that is bonded to two other carbon atoms.

Refer to Figure 18.13 of the citric acid cycle and locate the molecules that contain secondary alcohol functional groups. Common examples in the cycle include isocitrate.

Determine the reactions in the citric acid cycle where these secondary alcohols are oxidized. Oxidation involves the loss of hydrogen atoms or electrons, often facilitated by enzymes such as dehydrogenases.

Observe the conversion of isocitrate to α-ketoglutarate. This reaction involves the oxidation of the secondary alcohol group in isocitrate to form a ketone group in α-ketoglutarate, catalyzed by isocitrate dehydrogenase.

Confirm that the oxidation of secondary alcohols in the citric acid cycle is coupled with the reduction of NAD⁺ to NADH, which is a hallmark of oxidative reactions in metabolic pathways.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Citric Acid Cycle

The citric acid cycle, also known as the Krebs cycle, is a series of enzymatic reactions that occur in the mitochondria, playing a crucial role in cellular respiration. It involves the oxidation of acetyl-CoA to produce energy in the form of ATP, as well as electron carriers like NADH and FADH2. Understanding this cycle is essential for identifying where specific reactions, such as the oxidation of secondary alcohols, take place.

Oxidation of Alcohols

Oxidation of alcohols refers to the chemical process where alcohols lose electrons, often resulting in the formation of carbonyl compounds. In the context of the citric acid cycle, secondary alcohols are typically oxidized to ketones. This transformation is facilitated by specific enzymes, and recognizing these reactions is vital for understanding metabolic pathways and energy production.

Enzymatic Reactions

Enzymatic reactions are biochemical processes catalyzed by enzymes, which are proteins that speed up chemical reactions without being consumed. In the citric acid cycle, various enzymes facilitate the oxidation of substrates, including secondary alcohols. Identifying the specific enzymes involved in these reactions is key to understanding how the cycle operates and how energy is generated in cells.

Refer to the diagram of the citric acid cycle in Figure 18.13 to answer each of the following:d. In which reactions are secondary alcohols oxidized?