FBISE, NCP & NBF-aligned resources for Classes 9–12
Browse by Class
Browse by Type
Biology Chapter 7 : Topic 4
Factors Affecting Enzyme Activity
1 / 15
Which factor directly affects the rate at which an enzyme catalyzes a reaction?
Reasoning: All these factors can influence enzyme activity and reaction rate.
2 / 15
As temperature increases from low values to the optimum temperature, enzyme activity generally:
Reasoning: Higher temperature increases molecular collisions until the optimum temperature is reached.
3 / 15
Why does enzyme activity decrease above the optimum temperature?
Reasoning: Excessive heat changes the enzyme's shape, especially its active site.
4 / 15
What is meant by the optimum temperature of an enzyme?
Reasoning: Optimum temperature is where the enzyme functions most efficiently.
5 / 15
A digestive enzyme works best at pH 2. In which organ is it most likely active?
Reasoning: The stomach provides a highly acidic environment (around pH 2).
6 / 15
What happens when an enzyme is exposed to a highly unsuitable pH?
Reasoning: Extreme pH can alter the enzyme's active site.
7 / 15
Which statement best describes the optimum pH of an enzyme?
Reasoning: Every enzyme has a pH at which its activity is greatest.
8 / 15
If enzyme concentration increases while substrate remains abundant, the reaction rate will:
Reasoning: More enzyme molecules provide more active sites for reactions.
9 / 15
Why does increasing enzyme concentration increase reaction rate?
Reasoning: Additional enzymes provide more sites for substrate binding.
10 / 15
Increasing substrate concentration usually increases enzyme activity because:
Reasoning: More substrate molecules collide with enzyme active sites.
11 / 15
At very high substrate concentration, the reaction rate eventually levels off because:
Reasoning: Once all active sites are occupied, adding more substrate has little effect.
12 / 15
A student heats an enzyme solution from 25°C to 40°C and observes increased activity. The most likely reason is:
Reasoning: Higher temperatures increase collision frequency up to the optimum level.
13 / 15
Which factor can permanently alter the shape of an enzyme's active site?
Reasoning: Extreme heat causes denaturation.
14 / 15
What is denaturation?
Reasoning: Denaturation changes the active site's shape.
15 / 15
If the pH of an enzyme's environment changes from its optimum value, the enzyme activity usually:
Reasoning: The active site may be altered, reducing enzyme efficiency.
Your score is
Restart quiz
