The Question is from neet-botany respiration-in-plants , and it was created by the author B VENKAT

Question

In alcoholic fermentation, pyruvate is converted to ethanol. What is the intermediate molecule formed before ethanol?

B VENKAT · Accepted Answer

## CORE INFORMATION
✓ **Answer**: B
## CONCEPT FRAMEWORK
 **Primary Concept**: Alcoholic Fermentation
 **Related Topics**: Glycolysis, Cellular Respiration, Metabolic Pathways
 **Prerequisites**: Understanding of basic biochemistry and metabolic processes.
## SOLUTION PATHWAY
**Given Information**:
  Pyruvate is converted to ethanol in alcoholic fermentation.
  We need to identify the intermediate molecule.
**Method & Steps**:
 1. Understand the process of alcoholic fermentation.
  Reasoning: Alcoholic fermentation is an anaerobic process that converts pyruvate to ethanol and carbon dioxide, regenerating NAD+ in the process.  This is crucial for the continuation of glycolysis.
  Formula/Rule:  The overall reaction can be summarized as:  $C_3H_4O_3 ightarrow C_2H_5OH + CO_2$
 2. Identify the intermediate step between pyruvate and ethanol.
  Working: Pyruvate is first decarboxylated (loses a carboxyl group as $CO_2$), forming acetaldehyde.  Then, acetaldehyde is reduced (gains electrons) to form ethanol, using NADH as a reducing agent.
  Key Point: The decarboxylation step is catalyzed by pyruvate decarboxylase, and the reduction step is catalyzed by alcohol dehydrogenase.
 3. Determine the intermediate molecule.
  Result: Acetaldehyde is the intermediate molecule formed before ethanol in alcoholic fermentation.
  Verification: The reaction pathway confirms that acetaldehyde is the necessary intermediate.
 ## OPTION ANALYSIS
A :x: Citrate is a molecule involved in the citric acid cycle (Krebs cycle), not alcoholic fermentation.
B ✓: Acetaldehyde is the correct intermediate in the conversion of pyruvate to ethanol.
C :x: Lactate is the end product of lactic acid fermentation, a different anaerobic pathway.
D :x: Acetyl-CoA is an intermediate in the citric acid cycle and is not directly involved in alcoholic fermentation.
 ## LEARNING AIDS
 **Common Mistakes**:
  1.Confusing alcoholic fermentation with lactic acid fermentation: Remember that lactic acid fermentation produces lactate, not ethanol.
  2.Forgetting the two-step process:  The conversion of pyruvate to ethanol involves both decarboxylation and reduction, not a single step.
 **Quick Tips**:
  1.Remember that alcoholic fermentation regenerates NAD+, allowing glycolysis to continue in anaerobic conditions.
  2.Acetaldehyde is a key intermediate in the process; its presence indicates alcoholic fermentation.

B VENKAT · Answer

Citrate

B VENKAT · Answer

The correct Option is "Acetaldehyde"

B VENKAT · Answer

Lactate

B VENKAT · Answer

Acetyl-CoA

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