How many ATP molecules produced from the complete oxidation of a glucose in aerobic prokaryotes ?

Options

A. 2 ATP
B. 4 ATP
C. 38 ATP
D. 36 ATP

Answer

To determine how many ATP molecules are produced from the complete oxidation of glucose in aerobic prokaryotes, we can follow these steps:

### Step 1: Understanding Aerobic Respiration
Aerobic respiration is a metabolic process that requires oxygen to convert glucose into energy. In prokaryotes (like bacteria), this process occurs entirely in the cytoplasm since they lack mitochondria.

**Hint:** Remember that prokaryotes do not have membrane-bound organelles, which affects where respiration occurs.

### Step 2: Glycolysis
The first step in aerobic respiration is glycolysis, where one glucose molecule (C6H12O6) is broken down into two molecules of pyruvate. This process yields a net gain of 2 ATP molecules and produces 2 NADH molecules.

**Hint:** Glycolysis is the first stage of cellular respiration and occurs in the cytoplasm.

### Step 3: Conversion of Pyruvate
In aerobic conditions, the pyruvate produced in glycolysis is converted into Acetyl-CoA, which enters the Krebs cycle. This step does not produce ATP directly but generates NADH.

**Hint:** Pyruvate is a key intermediate that links glycolysis to the Krebs cycle.

### Step 4: Krebs Cycle
Each Acetyl-CoA enters the Krebs cycle (also known as the citric acid cycle), which occurs in the cytoplasm for prokaryotes. For each glucose molecule, two Acetyl-CoA molecules are produced, leading to:
- 6 NADH
- 2 FADH2
- 2 ATP

**Hint:** The Krebs cycle is crucial for producing electron carriers that will be used in the electron transport chain.

### Step 5: Electron Transport Chain
The NADH and FADH2 produced in glycolysis and the Krebs cycle are then used in the electron transport chain (ETC). In prokaryotes, the ETC is located in the cell membrane. Each NADH can produce approximately 3 ATP, and each FADH2 can produce about 2 ATP.

Calculating the ATP from the electron transport chain:
- From 10 NADH (2 from glycolysis + 6 from Krebs + 2 from conversion of pyruvate), we get: 10 NADH × 3 ATP/NADH = 30 ATP
- From 2 FADH2 (from Krebs), we get: 2 FADH2 × 2 ATP/FADH2 = 4 ATP

Total ATP from the electron transport chain = 30 ATP + 4 ATP = 34 ATP

### Step 6: Total ATP Production
Now, we add the ATP produced from glycolysis, Krebs cycle, and the electron transport chain:
- Glycolysis: 2 ATP
- Krebs Cycle: 2 ATP
- Electron Transport Chain: 34 ATP

Total = 2 + 2 + 34 = 38 ATP

### Final Answer
The total number of ATP molecules produced from the complete oxidation of one glucose molecule in aerobic prokaryotes is **38 ATP**.

---