A general statement about enzyme specificity: Most enzymes act on specific substrates

A general statement about enzyme specificity: Most enzymes act on specific substrates

• A. Each enzyme can digest all substrates
• B. Many enzymes act on specific substrates
• C. Some enzymes are non-specific to any substrate
• D. Enzymes are not affected by pH

Answer: (B)

Enzyme specificity comes from the active site being a unique fit for particular substrates—the shape and chemical environment favor binding to specific molecules and not to others. This selective binding, explained by the lock-and-key or induced-fit view, means most enzymes catalyze reactions for a single substrate (or a small group of related ones), which is why the statement about specificity is true. The other ideas don’t fit because an enzyme generally doesn’t digest every substance, some enzymes do show broader—but still not universal—specificity, and enzyme activity can be strongly influenced by pH, since changes in protonation affect the active site and overall structure.

Enzyme specificity comes from the active site being a unique fit for particular substrates—the shape and chemical environment favor binding to specific molecules and not to others. This selective binding, explained by the lock-and-key or induced-fit view, means most enzymes catalyze reactions for a single substrate (or a small group of related ones), which is why the statement about specificity is true. The other ideas don’t fit because an enzyme generally doesn’t digest every substance, some enzymes do show broader—but still not universal—specificity, and enzyme activity can be strongly influenced by pH, since changes in protonation affect the active site and overall structure.