Lactate Dehydrogenase

The video explains the role of lactate dehydrogenase in regenerating NAD during anaerobic conditions. It discusses NADH production in glycolysis and the TCA cycle, and how enzymes like cytochrome C oxidase and NADH ubiquinone oxidoreductase are affected by the absence of oxygen. The video highlights the importance of lactate dehydrogenase in maintaining glycolysis by converting pyruvate to lactate, especially in anaerobic conditions like during intense exercise or heart attacks. It also compares ATP production in aerobic and anaerobic metabolism, emphasizing the inefficiency of anaerobic glycolysis.

What is the primary role of lactate dehydrogenase in glycolysis?

• To regenerate NAD from NADH

• To oxidize fatty acids

• To produce ATP directly

• To convert pyruvate to glucose

Which enzyme is dependent on cytochrome C oxidase in the electron transport chain?

• NADH ubiquinone oxidoreductase

• Glyceraldehyde 3-phosphate dehydrogenase

• Lactate dehydrogenase

• Pyruvate dehydrogenase

What happens to NAD levels when NADH builds up in anaerobic conditions?

• NAD is converted to ATP

• NAD levels increase

• NAD levels decrease

• NAD levels remain constant

What is the metabolic fate of lactate in humans under anaerobic conditions?

• It is converted to glucose

• It is stored as glycogen

• It is a dead-end metabolite

• It is used in the TCA cycle

How does the presence of oxygen affect cytochrome C oxidase?

• It converts it to lactate

• It inhibits the enzyme

• It has no effect

• It acts as a substrate

What is the consequence of prolonged anaerobic metabolism in heart cells?

• Increased ATP production

• Cellular repair and growth

• Cell death and myocardial infarction

• Conversion of lactate to glucose

What is the primary energy source for heart cells under normal conditions?

• Aerobic metabolism

• Fatty acid oxidation

• Anaerobic glycolysis

• Lactic acid fermentation

What is the role of lactate dehydrogenase during anaerobic glycolysis?

• To produce ATP

• To convert lactate to pyruvate

• To regenerate NAD

• To oxidize glucose

What is the effect of blocking a coronary artery on heart tissue?

• Increased ATP production

• Increased oxygen supply

• Decreased blood flow and oxygen

• Enhanced aerobic metabolism

What is the main purpose of lactic acid fermentation?

• To produce acetyl CoA

• To regenerate NAD

• To produce glucose

• To oxidize fatty acids