Released STAAR Biology EOC · 2026 · Item 24 · 1 point

Walkthrough: Biology 2026, Item 24

B.11B · Enzymes · unscored study

A graph of enzyme activity percent against decreasing acidity. Pepsin, a dashed curve, peaks at 100 percent in the most acidic conditions and drops to zero as acidity decreases. Amylase, a solid curve, is zero in acidic conditions and rises toward 100 percent in less acidic conditions. Source: Le Feunteun, S., et al., Trends in Food Science and Technology, 2021. — Enzyme activity versus pH for pepsin and amylaseOriginal visual from the released STAAR test.

The graph shows the reaction rates for two different enzymes at different pH levels. Each enzyme is used in the body for different reactions: • Pepsin is used in the stomach to help digest proteins. • Amylase is used in the mouth to help digest sugars. Which statement BEST describes what will happen when amylase is swallowed and enters the stomach?

Amylase will continue to break down sugars in the stomach.
Amylase will help the stomach break down proteins.
Amylase will be recycled for use in other systems.
Amylase will be unable to function in the stomach.

1. Understand the question

Read the pH graph for amylase, then think about where amylase goes: from the mouth into the acidic stomach.

Try the question on your own first, then reveal one step at a time.

2. Solve it step by step

Practice released items for this skill Back to the lesson

Question, artwork, answer key and rationale: Texas Education Agency released STAAR test. Walkthrough steps written by TEKSForge. Studying here does not change your mastery or scores.