The number of metabolic steps required for the oxidation of glucose to form lactic acid

Options

A. 8
B. 9
C. 10
D. 11

Answer

To determine the number of metabolic steps required for the oxidation of glucose to form lactic acid, we can break down the process as follows:

### Step 1: Understand Glycolysis
- Glycolysis is the first stage of glucose metabolism, where glucose (a 6-carbon molecule) is broken down into two molecules of pyruvate (a 3-carbon molecule).
- This process occurs in the cytoplasm and consists of a series of enzymatic reactions.

### Step 2: Count the Steps in Glycolysis
- Glycolysis consists of **10 metabolic steps**. Each step involves a specific enzyme that catalyzes the conversion of substrates into products.

### Step 3: Conversion of Pyruvate to Lactic Acid
- In the absence of oxygen (anaerobic conditions), pyruvate is converted into lactic acid through a process called lactic acid fermentation.
- This conversion is a single step where pyruvate is reduced to lactic acid, and NADH is oxidized to NAD+.

### Step 4: Total Steps Calculation
- To find the total number of metabolic steps for the complete process:
- **10 steps from glycolysis** + **1 step for the conversion of pyruvate to lactic acid** = **11 total steps**.

### Conclusion
- Therefore, the total number of metabolic steps required for the oxidation of glucose to form lactic acid is **11**.

### Answer
- The correct option is **D (11)**.

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