Enzymes

Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.

Enzyme action

Subtopic

Enzyme action under Enzymes for Grade 12 IGCSE.

About Topic & Revision

Preview questions (no answers)

1.
$If the concentration of substrate is increased while the enzyme concentration remains constant, what eventually happens to the rate of reaction?$
A. $It increases forever$
B. $It decreases to zero$
C. $It levels off as all active sites are occupied$
D. $It fluctuates up and down$
2.
$At which pH would a pancreatic enzyme (which works in the small intestine) likely have its optimum activity?$
A. $pH 2$
B. $pH 8$
C. $pH 1$
D. $pH 14$
3.
$Which statement best describes the Lock and Key hypothesis?$
A. $Enzymes can fit any substrate if heated$
B. $One enzyme can catalyze many different types of reactions$
C. $The substrate shape is complementary to the enzyme's active site$
D. $Substrates change shape to fit into any enzyme$

Download the worksheet for Enzymes - Enzyme action to practice offline. It includes additional chapter-level practice questions.

Effects of temperature and pH

Subtopic

Effects of temperature and pH under Enzymes for Grade 12 IGCSE.

About Topic & Revision

Preview questions (no answers)

1.
$When temperature increases, molecules move faster. This increases the frequency of:$
A. $Substrate evaporation$
B. $Effective collisions between enzyme and substrate$
C. $Enzyme production$
D. $pH changes$
2.
$Which enzyme would be most active in a neutral environment?$
A. $Pepsin (optimum pH 2)$
B. $Trypsin (optimum pH 8)$
C. $Salivary amylase (optimum pH 7)$
D. $Lipase (optimum pH 9)$
3.
$What is the primary role of enzymes in the human body?$
A. $To provide energy for movement$
B. $To act as structural components of bones$
C. $To speed up metabolic reactions$
D. $To store genetic information$

Download the worksheet for Enzymes - Effects of temperature and pH to practice offline. It includes additional chapter-level practice questions.