GATE BT 2025 • Q49
MSQ • 2 Marks
Section 2: General Biotechnology
Bioenergetics and Metabolism
Subtopic: Thermodynamics & ATP Bioenergetics
Question Statement:
Which of the following statements is/are true regarding the effect of the
concentration of metabolic intermediates on glycolysis in erythrocytes?
Options:
-
(A) Increased AMP levels stimulate glycolysis
-
(B) Increased citrate inhibits glycolysis
-
(C) Increased glucose 6-phosphate inhibits glycolysis
-
(D) Increased fructose 1,6-bisphosphate stimulates glycolysis
Official Answer Key:
A;B;D
Step-by-Step Solution & Explanation
### **Official Solution & Concept Analysis (GATE BT 2025 Q.49)**
**1. Governing Concept**:
- **Topic**: Enzyme Kinetics & Michaelis-Menten Mechanism
- In uninhibited Michaelis-Menten kinetics:
$v_0 = \frac{V_{\max} [S]}{K_m + [S]} = \frac{k_{\text{cat}} [E]_t [S]}{K_m + [S]}$
- $V_{\max} = k_{\text{cat}} [E]_t$: Proportional to total enzyme concentration.
- $K_m$: Intrinsic kinetic constant reflecting substrate affinity (independent of $[E]_t$).
- At $[S] \ll K_m$ (first-order regime): $v_0 \approx \left(\frac{V_{\max}}{K_m}\right) [S]$; velocity depends linearly on substrate concentration.
- At $[S] \gg K_m$ (zero-order regime): $v_0 \approx V_{\max}$; reaction rate becomes independent of substrate concentration.
**2. Option Analysis**:
- **Option (A) is CORRECT**: $V_{\max}$ is directly proportional to the total enzyme concentration ($[E]_t$).
- **Option (B) is CORRECT**: At high substrate concentrations ($[S] \gg K_m$), the reaction velocity is zero-order with respect to substrate and independent of $[S]$.
- **Option (C) is INCORRECT**: $K_m$ is an intensive property of the enzyme-substrate pair and does not depend on enzyme concentration.
- **Option (D) is CORRECT**: At low substrate concentrations ($[S] \ll K_m$), reaction rate exhibits first-order dependence on $[S]$.
**3. Final Answer**:
- **Correct Options**: **A, B, D**
Practice This in Real CBT Exam Interface
Test yourself with the official TCS-iON palette, virtual calculator, and immediate performance analytics.
Launch CBT Mock Test