Table of contents

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

21. The Generation of Biochemical Energy

The Citric Acid Cycle

GOB Chemistry

21. The Generation of Biochemical Energy

The Citric Acid Cycle

Previous problemNext problem

4:46 minutes

Problem 15

Textbook Question

Which of the reactants in the citric acid cycle have two chiral carbon atoms?

Verified step by step guidance

Understand the citric acid cycle: The citric acid cycle (also known as the Krebs cycle or TCA cycle) is a series of chemical reactions used by aerobic organisms to generate energy through the oxidation of acetyl-CoA. It involves several intermediates, some of which are chiral molecules.

Review the concept of chirality: A chiral carbon atom is a carbon atom that is bonded to four different groups. Molecules with chiral carbons can exist as non-superimposable mirror images (enantiomers).

Identify the intermediates in the citric acid cycle: The main intermediates include citrate, isocitrate, α-ketoglutarate, succinyl-CoA, succinate, fumarate, malate, and oxaloacetate. Not all of these intermediates are chiral.

Determine which intermediates have two chiral carbons: Analyze the molecular structure of each intermediate. For example, isocitrate has two chiral carbons because it contains two carbon atoms each bonded to four different groups.

Conclude that isocitrate is the reactant in the citric acid cycle with two chiral carbon atoms. Other intermediates may have one or no chiral carbons, but isocitrate specifically has two.

Verified video answer for a similar problem:

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

Video duration:

Play a video:

Was this helpful?

Key Concepts

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

Chirality

Chirality refers to the geometric property of a molecule having a non-superimposable mirror image, much like left and right hands. A chiral carbon atom is one that is attached to four different substituents, leading to two distinct configurations, known as enantiomers. Understanding chirality is essential in biochemistry, as it can influence the behavior and interaction of molecules in biological systems.

Citric Acid Cycle

The citric acid cycle, also known as the Krebs cycle, is a key metabolic pathway that occurs in the mitochondria of cells. It plays a crucial role in cellular respiration by oxidizing acetyl-CoA to produce energy in the form of ATP, as well as electron carriers like NADH and FADH2. The cycle involves a series of enzymatic reactions, and understanding its components is vital for identifying reactants with specific structural features, such as chirality.

Reactants in the Citric Acid Cycle

The reactants in the citric acid cycle include acetyl-CoA, oxaloacetate, and various intermediates such as citrate, isocitrate, and alpha-ketoglutarate. Each of these compounds plays a specific role in the cycle, and some contain chiral centers. Identifying which of these reactants have two chiral carbon atoms requires knowledge of their molecular structures and the ability to recognize chiral centers within them.

Watch next

Master Phase A - Citrate Formation Concept 1 with a bite sized video explanation from Jules

Start learning

Related Videos

Related Practice

Multiple Choice

Complete the following net equation for one turn of the citric acid cycle.

Acetyl CoA + __H₂O + 3 NAD+ + FAD + GDP + ____ ⭢ CoA + ___NADH + ___H⁺ + FADH₂ + GTP + ___CO₂

547

views

Textbook Question

Look ahead to Figure 21.8 for the citric acid cycle.

<IMAGE>

a. Draw the structures of the reactants in steps 3, 6, and 8, and indicate which hydrogen atoms are removed in these reactions.

576

views

Textbook Question

Why, do you suppose, the coenzyme for the reaction in the citric acid cycle that is catalyzed by succinate dehydrogenase is FAD and not NAD⁺?

1055

views

Textbook Question

Identify the participants in the citric acid cycle that contain alcohol groups. Identify these groups as primary, secondary, or tertiary alcohols.

681

views

Textbook Question

Since no molecular oxygen participates in the citric acid cycle, the steps in which acetyl groups are oxidized to CO₂ involve removal of hydride ions and hydrogen ions. What is the acceptor of hydride ions? What is the acceptor of hydrogen ions?

559

views

Textbook Question

What is the final fate of the carbons in acetyl-CoA after several turns of the citric acid cycle?

997

views

Textbook Question

Look at the eight steps of the citric acid cycle (Figure 21.8) and answer the following questions:

a. Which steps involve oxidation reactions?

408

views

Textbook Question