Energy Systems and Enzymes Quiz

What is the only direct energy source for muscle contraction?

• Glucose

• ATP

• Phosphocreatine

• Glycogen

Which enzyme breaks down ATP into ADP + Pi + Energy?

• Creatine kinase

• Lactate dehydrogenase

• ATPase

• Phosphofructokinase

How long does the ATP-PC system typically last?

• 2–3 minutes

• 30–60 seconds

• 8–10 seconds

• 5 minutes

What is the main by-product of anaerobic glycolysis?

• Carbon dioxide

• Lactic acid

• Water

• Oxygen debt

Which system produces the highest ATP yield per glucose molecule?

• ATP-PC system

• Anaerobic glycolysis

• Aerobic glycolysis (with Krebs + ETC)

• Beta-oxidation

Which enzyme converts pyruvate into lactic acid?

• Lactate dehydrogenase (LDH)

• Glycogen phosphorylase

• Phosphofructokinase (PFK)

• ATPase

Which energy system is dominant in a 400m sprint?

• ATP-PC system

• Anaerobic glycolysis

• Aerobic glycolysis

• Beta-oxidation

Which fuel source requires the most oxygen to break down?

• Protein

• Glycogen

• Fatty acids

• ATP

The breakdown of ATP into ADP + Pi releases __________ for muscle contraction.

The fuel for the ATP-PC system is __________.