Subtopic: Fundamentals of Downstream processing (chromatography, filtration)
Question Statement:
Which of the following is(are) COMMON feature(s) for both aerobic and
anaerobic bacterial cultures?
Options:
(A) At low glucose level, the operon is activated
(B) At high glucose level, the operon is activated to enable the utilization of lactose
(C) The lac repressor binds to operator region inactivating the operon
(D) Binding of lactose to the lac repressor induces the operon
Official Answer Key:
A;B
Step-by-Step Solution & Explanation
### **Official Solution & Concept Analysis (GATE BT 2022 Q.49)**
**1. Governing Concept**:
- **Topic**: Microbiology & Microbial Respiration
- Aerobic and anaerobic bacteria utilize electron transport chains and substrate-level phosphorylation to generate energy:
- Both pathways utilize **glycolysis** or related central pathways to generate reducing equivalents (NADH, $\text{FADH}_2$).
- Both employ membrane-bound electron transport chains that generate a **proton motive force (PMF)** via chemiosmotic proton translocation.
- Both use membrane-bound **$F_oF_1$-ATP synthase** to generate ATP by rotary catalysis driven by PMF.
- The key difference lies in the **terminal electron acceptor**: Aerobic bacteria use molecular oxygen ($O_2$), while anaerobic bacteria use alternative inorganic/organic terminal acceptors ($\text{NO}_3^-$, $\text{SO}_4^{2-}$, fumarate, $\text{Fe}^{3+}$).
**2. Option Analysis**:
- **Option (A) [Generation of proton motive force across the membrane] is CORRECT**: Found in both aerobic and anaerobic respiratory systems.
- **Option (B) [ATP synthesis mediated by ATP synthase] is CORRECT**: Chemiosmotic phosphorylation operates via $F_oF_1$-ATP synthase in both.
- **Option (C) [Oxygen acts as the terminal electron acceptor] is INCORRECT**: Oxygen serves as terminal acceptor only in aerobic respiration.
- **Option (D) is INCORRECT**: Anaerobic respiration is distinct from fermentation and utilizes membrane electron transport.
**3. Final Answer**:
- **Correct Options**: **A, B**
Practice This in Real CBT Exam Interface
Test yourself with the official TCS-iON palette, virtual calculator, and immediate performance analytics.