The Citric Acid Cycle

Steps

100

Step 1 of the Citric Acid Cycle

What is the reaction between Oxaloacetate and Acetyl-CoA to form Citrate?

200

The step that converts Isocitrate to alpha-Ketoglutarate

What is Step 3?

300

Step 4 of the Citric Acid Cycle

What is the conversion of alpha-Ketoglutarate to Succinyl-CoA?

400

The steps that convert Succinyl-CoA to Succinate and Succinate to Fumarate

What are steps 5 and 6?

500

The last 2 steps of the Citric Acid Cycle

What is the conversion of Fumarate to Malate and Malate to Oxaloacetate?

Enzymes

100

The enzyme that catalyzes step 3 of the Citric Acid Cycle

What is Isocitrate dehydrogenase?

200

This enzyme catalyzes the conversion reaction of Succinate to Fumarate in the Citric Acid Cycle

What is Succinate dehydrogenase?

300

The enzymes that catalyze steps 1 and 2 of the Citric Acid Cycle

What is Citrate synthase and Aconitase?

400

Fumarase and Malate dehydrogenase catalyze these conversion reactions in the Citric Acid cycle

What is the conversion from Fumarate to Malate and Malate to Oxaloacetate?

500

The enzymes that catalyze the reactions of steps 4 and 5 of the Citric Acid Cycle

What is alpha-Ketoglutarate and Succinyl-CoA synthetase?

Byproducts and Electron Carriers

100

These steps of the Citric Acid Cycle produce CO₂ as a byproduct

What is step 3 and 4?

200

This electron carrier is reduced in steps 3, 4, and 8 of the Citric Acid Cycle

What is NAD+/NADH?

300

This step of the Citric Acid Cycle produces ATP and CoA-SH

What is step 5?

400

The only byproduct of step 1 of the Citric Acid Cycle

What is CoA-SH?

500

This step of the Citric Acid Cycle reduces the electron carrier FAD to FADH₂

What is step 6?

Intermediates and Other Metabolic Pathways

100

This metabolic pathway produces Fumarate that feeds back into the Citric Acid Cycle

What is the Urea Cycle?

200

Beta-oxidation produces this molecule that feeds into the Citric Acid Cycle

What is Acetyl-CoA?

300

This intermediate of the Citric Acid Cycle undergoes a transamination reaction to produce Aspartate to feed into the Urea Cycle

What is Oxaloacetate?

400

These intermediates of the Citric Acid Cycle participate in the “shuttling” of electrons to feed into the electron transport chain

What is Malate and alpha-ketoglutarate?

500

This intermediate from the Citric Acid Cycle can go through a transamination reaction to create Glutamate. 

What is alpha-Ketoglutarate?

Regulation

100

These steps of the Citric Acid Cycle are regulated

What is steps 1, 3, and 4

200

The increase of this electron carrier inhibits the regulatory steps of the Citric Acid Cycle.

What is NADH?

300

Steps 3 and 4 of the Citric Acid Cycle are _____ by increased levels of Ca²⁺.

What is stimulated?

400

These steps of the Citric Acid Cycle are inhibited by increased levels of Succinyl-CoA.

What is steps 1 and 4?

500

Increased levels of this byproduct inhibit step 3 of the Citric Acid Cycle.

What is ATP?