- What does the Michaelis-Menten equation describe?
A) Rate of photosynthesis
B) Enzyme-substrate interactions
C) Genetic inheritance patterns
D) Protein folding mechanisms
Answer: B) Enzyme-substrate interactions - What is VmaxV_{\text{max}} in the Michaelis-Menten equation?
A) Maximum enzyme concentration
B) Maximum rate of reaction
C) Maximum substrate concentration
D) Minimum rate of reaction
Answer: B) Maximum rate of reaction - What is KmK_m in the Michaelis-Menten equation?
A) Rate constant of enzyme reaction
B) Substrate concentration at half VmaxV_{\text{max}}
C) Maximum enzyme activity
D) Inhibitor constant
Answer: B) Substrate concentration at half VmaxV_{\text{max}} - What does a low KmK_m value indicate about an enzyme?
A) High substrate affinity
B) Low substrate affinity
C) High reaction rate
D) Low reaction rate
Answer: A) High substrate affinity - What shape does a Michaelis-Menten plot typically have?
A) Sigmoidal
B) Linear
C) Hyperbolic
D) Parabolic
Answer: C) Hyperbolic - Which step in enzyme kinetics is assumed to be in a steady state in the Michaelis-Menten model?
A) Formation of enzyme-substrate complex
B) Dissociation of enzyme-substrate complex
C) Conversion to product
D) Product release
Answer: A) Formation of enzyme-substrate complex - What is the Michaelis-Menten equation?
A) v=k[S]v = k[S]
B) v=Vmax[S]Km+[S]v = \frac{V_{\text{max}} [S]}{K_m + [S]}
C) v=Vmax+Km[S]v = V_{\text{max}} + K_m[S]
D) v=k[S]v = \frac{k}{[S]}
Answer: B) v=Vmax[S]Km+[S]v = \frac{V_{\text{max}} [S]}{K_m + [S]} - Which variable is used to represent the substrate concentration?
A) vv
B) KmK_m
C) [S][S]
D) VmaxV_{\text{max}}
Answer: C) [S][S] - What is the significance of VmaxV_{\text{max}}?
A) Maximum enzyme concentration
B) Reaction rate when all enzymes are saturated with substrate
C) Substrate concentration at saturation
D) Minimum velocity of reaction
Answer: B) Reaction rate when all enzymes are saturated with substrate - What does a Lineweaver-Burk plot represent?
A) Hyperbolic relationship of enzyme kinetics
B) Reciprocal of Michaelis-Menten equation
C) Sigmoidal kinetics of allosteric enzymes
D) Enzyme inhibition patterns
Answer: B) Reciprocal of Michaelis-Menten equation
- How does competitive inhibition affect KmK_m?
A) Increases KmK_m
B) Decreases KmK_m
C) No effect on KmK_m
D) Decreases VmaxV_{\text{max}}
Answer: A) Increases KmK_m - What effect does non-competitive inhibition have on VmaxV_{\text{max}}?
A) Increases VmaxV_{\text{max}}
B) Decreases VmaxV_{\text{max}}
C) No effect on VmaxV_{\text{max}}
D) Increases KmK_m
Answer: B) Decreases VmaxV_{\text{max}} - What kind of plot shows VmaxV_{\text{max}} as the y-intercept?
A) Hyperbolic plot
B) Lineweaver-Burk plot
C) Sigmoidal plot
D) Dixon plot
Answer: B) Lineweaver-Burk plot - What happens when substrate concentration is much greater than KmK_m?
A) Reaction velocity equals VmaxV_{\text{max}}
B) Reaction velocity equals KmK_m
C) Reaction velocity is zero
D) Enzyme is inactive
Answer: A) Reaction velocity equals VmaxV_{\text{max}} - How is catalytic efficiency expressed?
A) Kmkcat\frac{K_m}{k_{\text{cat}}}
B) kcat×Kmk_{\text{cat}} \times K_m
C) kcatKm\frac{k_{\text{cat}}}{K_m}
D) kcat−Kmk_{\text{cat}} – K_m
Answer: C) kcatKm\frac{k_{\text{cat}}}{K_m} - What does kcatk_{\text{cat}} represent?
A) Total reaction rate
B) Number of reactions per active site per unit time
C) Substrate binding affinity
D) Enzyme concentration
Answer: B) Number of reactions per active site per unit time - Which assumption is NOT part of the Michaelis-Menten model?
A) Steady-state assumption
B) Substrate concentration is much higher than enzyme concentration
C) Product inhibits enzyme activity
D) Initial reaction rate is measured
Answer: C) Product inhibits enzyme activity - What unit is KmK_m expressed in?
A) Moles per liter (MM)
B) Reaction rate (vv)
C) Time (ss)
D) Enzyme activity (UU)
Answer: A) Moles per liter (MM) - What is an enzyme’s turnover number?
A) KmK_m
B) kcatk_{\text{cat}}
C) VmaxV_{\text{max}}
D) [S][S]
Answer: B) kcatk_{\text{cat}} - What happens to VmaxV_{\text{max}} in the presence of uncompetitive inhibition?
A) Increases
B) Decreases
C) Remains constant
D) Increases and then decreases
Answer: B) Decreases
- What does a sigmoidal kinetics curve indicate?
A) Michaelis-Menten behavior
B) Allosteric enzyme activity
C) Competitive inhibition
D) First-order reaction
Answer: B) Allosteric enzyme activity - Which enzyme behavior deviates from Michaelis-Menten kinetics?
A) Single-substrate enzymes
B) Multi-substrate enzymes
C) Allosteric enzymes
D) Irreversible enzymes
Answer: C) Allosteric enzymes - What is the slope of a Lineweaver-Burk plot?
A) VmaxV_{\text{max}}
B) KmVmax\frac{K_m}{V_{\text{max}}}
C) 1Vmax\frac{1}{V_{\text{max}}}
D) KmK_m
Answer: B) KmVmax\frac{K_m}{V_{\text{max}}} - What does the term “saturation” mean in enzyme kinetics?
A) All substrate molecules are bound to enzymes
B) All enzyme active sites are occupied
C) Reaction has stopped
D) No substrate is present
Answer: B) All enzyme active sites are occupied - What happens at Km=[S]K_m = [S]?
A) Reaction velocity is VmaxV_{\text{max}}
B) Reaction velocity is half VmaxV_{\text{max}}
C) Reaction velocity is zero
D) Enzyme is inactive
Answer: B) Reaction velocity is half VmaxV_{\text{max}} - Which plot is used to analyze cooperative binding?
A) Lineweaver-Burk plot
B) Michaelis-Menten plot
C) Hill plot
D) Eadie-Hofstee plot
Answer: C) Hill plot - What is the reciprocal of KmK_m known as?
A) Substrate affinity
B) Inhibition constant
C) Turnover rate
D) Enzyme efficiency
Answer: A) Substrate affinity - What does the Michaelis-Menten constant reflect?
A) Enzyme turnover rate
B) Enzyme-substrate binding affinity
C) Reaction inhibition rate
D) Active site saturation
Answer: B) Enzyme-substrate binding affinity - Which condition defines zero-order kinetics in enzyme reactions?
A) [S]≫Km[S] \gg K_m
B) [S]≪Km[S] \ll K_m
C) Km=VmaxK_m = V_{\text{max}}
D) Enzyme is inactive
Answer: A) [S]≫Km[S] \gg K_m - What is the major limitation of the Michaelis-Menten model?
A) Assumes allosteric effects
B) Assumes constant substrate concentration
C) Ignores enzyme inhibition
D) Assumes steady-state conditions
Answer: D) Assumes steady-state conditions
