What is the best free Krebs cycle diagram generator?

ConceptViz offers a free AI-powered Krebs cycle diagram generator that creates professional citric acid cycle diagrams in seconds. Describe what you need — a complete labeled cycle, simplified overview, enzyme-focused diagram, or blank worksheet — and the AI generates a detailed, accurate diagram ready for study or publication.

How many ATP does the Krebs cycle produce?

Each turn of the Krebs cycle directly produces 1 GTP (equivalent to 1 ATP) through substrate-level phosphorylation. However, it also produces 3 NADH and 1 FADH2 per turn, which generate approximately 9 additional ATP through the electron transport chain (2.5 ATP per NADH, 1.5 ATP per FADH2). Since glucose yields 2 acetyl-CoA, the total from the Krebs cycle is about 20 ATP per glucose.

What are the 8 steps of the Krebs cycle?

The 8 steps are: (1) Citrate synthesis from acetyl-CoA + oxaloacetate, (2) Isomerization of citrate to isocitrate, (3) Oxidative decarboxylation to alpha-ketoglutarate (produces NADH + CO2), (4) Oxidative decarboxylation to succinyl-CoA (produces NADH + CO2), (5) Substrate-level phosphorylation producing GTP, (6) Oxidation of succinate to fumarate (produces FADH2), (7) Hydration of fumarate to malate, (8) Oxidation of malate to oxaloacetate (produces NADH).

Why is the Krebs cycle also called the citric acid cycle?

The Krebs cycle is called the citric acid cycle because citrate (citric acid) is the first product formed when acetyl-CoA combines with oxaloacetate in step 1. It is also called the tricarboxylic acid (TCA) cycle because citrate contains three carboxyl groups. Hans Krebs described the pathway in 1937 and received the Nobel Prize in 1953.

Where does the Krebs cycle take place?

The Krebs cycle takes place in the mitochondrial matrix of eukaryotic cells. Pyruvate from glycolysis is transported into the mitochondria and converted to acetyl-CoA by pyruvate dehydrogenase before entering the cycle. The NADH and FADH2 produced then transfer electrons to the electron transport chain in the inner mitochondrial membrane.

Can I create a blank Krebs cycle diagram for quizzes?

Yes, our AI generator can create blank Krebs cycle templates perfect for quizzes and worksheets. Simply request a blank diagram with numbered empty boxes for intermediates, enzymes, and products. Students can fill in the missing components to test their understanding of the pathway.

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Krebs Cycle Diagram Krebs Cycle

Describe the Krebs cycle diagram you need and our AI will create it instantly. Perfect for biochemistry courses, exam preparation, and research presentations.

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Krebs Cycle Diagram Generator

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Krebs Cycle Diagram Examples

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Complete Labeled Krebs Cycle

Complete Krebs cycle (citric acid cycle) diagram with all 8 enzymatic steps, intermediates, and energy carriers clearly labeled.

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Simplified Krebs Cycle Overview

Simplified overview of the Krebs cycle emphasizing major inputs (acetyl-CoA, NAD+, FAD) and outputs (NADH, FADH2, ATP, CO2).

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Krebs Cycle with Enzymes

Detailed Krebs cycle focusing on the 8 enzymes that catalyze each step, with regulatory enzymes highlighted.

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Energy Carrier Focus Diagram

Krebs cycle diagram focused on energy carrier production, showing exactly where NADH, FADH2, and ATP are generated.

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Krebs Cycle in Mitochondria Context

Krebs cycle positioned within the mitochondrial matrix, showing its connection to the electron transport chain and cellular respiration.

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Blank Krebs Cycle for Quiz

Blank Krebs cycle worksheet template with numbered empty boxes for students to fill in substrates, enzymes, and products.

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What is the Krebs Cycle?

The Krebs cycle, also known as the citric acid cycle or tricarboxylic acid (TCA) cycle, is a series of eight enzymatic reactions that occur in the mitochondrial matrix of eukaryotic cells. Discovered by Hans Krebs in 1937, this metabolic pathway is the central hub of cellular respiration, connecting carbohydrate, fat, and protein metabolism. The cycle oxidizes acetyl-CoA (derived from pyruvate, fatty acids, or amino acids) to produce CO2, while generating high-energy electron carriers NADH and FADH2 that feed into the electron transport chain for ATP production. Each complete turn of the cycle processes one acetyl group (2 carbons) and regenerates oxaloacetate to accept the next acetyl-CoA.

The 8 Steps of the Krebs Cycle

Step 1: Citrate synthase combines acetyl-CoA (2C) with oxaloacetate (4C) to form citrate (6C), releasing CoA
Step 2: Aconitase converts citrate to isocitrate through a dehydration-rehydration reaction
Step 3: Isocitrate dehydrogenase oxidizes isocitrate to alpha-ketoglutarate (5C), producing NADH and releasing CO2
Step 4: Alpha-ketoglutarate dehydrogenase converts alpha-ketoglutarate to succinyl-CoA (4C), producing NADH and releasing CO2
Step 5: Succinyl-CoA synthetase converts succinyl-CoA to succinate, producing GTP (or ATP) via substrate-level phosphorylation
Step 6: Succinate dehydrogenase oxidizes succinate to fumarate, producing FADH2 (the only enzyme embedded in the inner membrane)
Step 7: Fumarase hydrates fumarate to form malate
Step 8: Malate dehydrogenase oxidizes malate to regenerate oxaloacetate, producing the third NADH of the cycle

Key Molecules and Energy Output

Each turn of the Krebs cycle produces 3 NADH, 1 FADH2, 1 GTP (equivalent to ATP), and 2 CO2. Since each glucose molecule yields 2 acetyl-CoA (via pyruvate decarboxylation), the cycle turns twice per glucose, producing a total of 6 NADH, 2 FADH2, and 2 GTP. The key intermediates include citrate (6C), isocitrate (6C), alpha-ketoglutarate (5C), succinyl-CoA (4C), succinate (4C), fumarate (4C), malate (4C), and oxaloacetate (4C). The electron carriers NADH and FADH2 donate their electrons to the electron transport chain, ultimately driving oxidative phosphorylation to produce approximately 30-32 ATP per glucose molecule.

Connection to the Electron Transport Chain

The Krebs cycle is tightly coupled to the electron transport chain (ETC) located in the inner mitochondrial membrane. NADH donates electrons to Complex I, while FADH2 donates electrons to Complex II (succinate dehydrogenase, which is also a Krebs cycle enzyme). As electrons pass through the ETC complexes, protons are pumped across the inner membrane, creating a proton gradient that drives ATP synthase. Each NADH yields approximately 2.5 ATP, and each FADH2 yields approximately 1.5 ATP through oxidative phosphorylation. Without the ETC to regenerate NAD+ and FAD, the Krebs cycle would stall due to lack of electron acceptors.

Classroom and Study Applications

Biochemistry courses: Master the complete pathway with all enzymes, substrates, and regulatory mechanisms
Biology exams: Use labeled diagrams to memorize intermediates and energy carrier production points
Medical education: Understand metabolic disorders linked to Krebs cycle enzyme deficiencies
Blank diagram worksheets: Test knowledge with fill-in-the-blank cycle templates
Comparative metabolism: Study how the cycle connects to gluconeogenesis, amino acid synthesis, and fatty acid metabolism
Research presentations: Create publication-quality diagrams for papers and poster sessions

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What is the Krebs Cycle?

The 8 Steps of the Krebs Cycle

Step 1: Citrate synthase combines acetyl-CoA (2C) with oxaloacetate (4C) to form citrate (6C), releasing CoA

Step 2: Aconitase converts citrate to isocitrate through a dehydration-rehydration reaction

Step 3: Isocitrate dehydrogenase oxidizes isocitrate to alpha-ketoglutarate (5C), producing NADH and releasing CO2

Step 4: Alpha-ketoglutarate dehydrogenase converts alpha-ketoglutarate to succinyl-CoA (4C), producing NADH and releasing CO2

Step 5: Succinyl-CoA synthetase converts succinyl-CoA to succinate, producing GTP (or ATP) via substrate-level phosphorylation

Step 6: Succinate dehydrogenase oxidizes succinate to fumarate, producing FADH2 (the only enzyme embedded in the inner membrane)

Step 7: Fumarase hydrates fumarate to form malate

Step 8: Malate dehydrogenase oxidizes malate to regenerate oxaloacetate, producing the third NADH of the cycle

Key Molecules and Energy Output

Connection to the Electron Transport Chain

Classroom and Study Applications

Biochemistry courses: Master the complete pathway with all enzymes, substrates, and regulatory mechanisms

Biology exams: Use labeled diagrams to memorize intermediates and energy carrier production points

Medical education: Understand metabolic disorders linked to Krebs cycle enzyme deficiencies

Blank diagram worksheets: Test knowledge with fill-in-the-blank cycle templates

Comparative metabolism: Study how the cycle connects to gluconeogenesis, amino acid synthesis, and fatty acid metabolism

Research presentations: Create publication-quality diagrams for papers and poster sessions