TCA / Krebs Cycle / Citric Acid Cycle - Basics for Beginners - Biochemistry Lesson

The video tutorial explains the tricarboxylic acid cycle, also known as the Krebs or Citric Acid Cycle. It covers the conversion of pyruvate to Acetyl CoA, the formation of citrate, and the subsequent steps leading to the regeneration of oxaloacetate. The tutorial highlights the regulatory mechanisms of key enzymes and the energy yield from the cycle, including ATP, NADH, and FADH2 production. It also provides mnemonic aids for remembering the sequence of reactions and discusses the energy efficiency of the cycle.

Who first described the Krebs Cycle?

• Albert Einstein

• Hans Krebs

• Marie Curie

• Isaac Newton

What is the role of pyruvate dehydrogenase in the Krebs Cycle?

• Converts pyruvate to glucose

• Converts citrate to isocitrate

• Converts pyruvate to Acetyl CoA

• Converts Acetyl CoA to citrate

Which enzyme catalyzes the formation of citrate from Acetyl CoA and oxaloacetate?

• Alpha-ketoglutarate dehydrogenase

• Isocitrate dehydrogenase

• Citrate synthase

• Aconitase

What is the main regulatory factor for citrate synthase?

• Temperature

• pH level

• Energy status of the cell

• Concentration of water

Which enzyme converts isocitrate to alpha-ketoglutarate?

• Malate dehydrogenase

• Citrate synthase

• Isocitrate dehydrogenase

• Aconitase

What is produced during the conversion of alpha-ketoglutarate to succinyl CoA?

• NADH and CO2

• FADH2

• ATP

• Water

Which enzyme is responsible for the conversion of succinate to fumarate?

• Citrate synthase

• Fumarase

• Succinate dehydrogenase

• Malate dehydrogenase

How many NADH molecules are produced per cycle of the Krebs Cycle?

• 3

• 1

• 4

• 2

What mnemonic can help remember the order of compounds in the Krebs Cycle?

• ATP

• F MOX

• CITRATE

• GLYCOLYSIS

What is the estimated ATP yield from one turn of the Krebs Cycle according to some textbooks?

• 8 ATP

• 10 ATP

• 12 ATP

• 14 ATP