Question

The diagram represents ethanol fermentation, Identity the labeling 1, 2 and 3

• A. 1. The glucose breaks down into two pyruvates.
  
  2. The pyruvate is broken down into acetaldehyde by releasing CO₂.
  
  3. The acetaldehyde is then converted to ethanol.
  
  
• B. 1. The glucose breaks down into two pyruvates.
  
  2. The acetaldehyde is then converted to ethanol.
  
  3. The pyruvate is broken down into acetaldehyde by releasing CO₂.
  
  
• C. 1. The glucose breaks down into two acetaldehydes
  
  2. The acetaldehyde is then converted to ethanol.
  
  3. The pyruvate is broken down into acetaldehyde by releasing CO₂.
• D. 1. The glucose breaks down into two pyruvates.
  
  2. The pyruvate is broken down into acetaldehyde by releasing NH₃.
  
  3. The acetaldehyde is then converted to ethanol.

Answer 1

Answer: (A)

During ethanol fermentation, one glucose molecule breaks down into two pyruvic acids the energy released from this exothermic reaction is used to bind the inorganic phosphates to ADP and convert NAD+ to NADH. The pyruvic acids are broken down into acetaldehydes and give off CO₂. The two acetaldehydes are then converted to two ethanol by using the H+ ions from NADH, converting NADH back into NAD+.