Question

21.the equation below summarizes the process that produces the flashing light of a firefly. luciferin atp heat + light luciferase the molecule luciferin is broken down, and energy is released in the form of heat and light. in this process, luciferase functions as a. a reactant b. a product c. a starch d. an enzyme 22.base your answer on the graph and on your knowledge of biology. the most likely result of mixing both enzymes with their substrates in a single test tube is that a. only gastric protease would be active if the ph of the mixture was basic b. intestinal protease would be more active than gastric protease at ph 4. c. both enzymes would exhibit some activity at ph 5. d. gastric protease would be more active that intestinal protease at ph 6 23.base your answer on the graph and on your knowledge of biology. which is a true statement about the relationship between ph and enzyme action? a. all enzymes work best at a neutral ph. b. adding more acid does not affect the rate of activity of an enzyme. c. enzymes function only in a ph range of 4.0 to 5.5. d. the activity of an enzyme is affected by ph. 24.how do you know a chemical reaction has occurred? ____________

Explanation:

Question 21

Enzymes are biological catalysts that speed up chemical reactions. In the given reaction \(luciferin\xrightarrow[luciferase]{ATP}heat + light\), luciferase is facilitating the breakdown of luciferin. Reactants (\(A\)) are the substances that undergo a reaction (luciferin and ATP here). Products (\(B\)) are what is formed (heat and light). Starch (\(C\)) is a carbohydrate, not relevant here. Since luciferase is speeding up the reaction (as enzymes do), it functions as an enzyme.

• Option A: Gastric protease has its optimal activity in an acidic environment (around pH 2 - 3). If the pH is basic, gastric protease would be inactive.
• Option B: At pH 4, looking at the graph, gastric protease has a higher relative rate of enzyme action compared to intestinal protease.
• Option C: At pH 5, by observing the graph, both enzymes have some non - zero relative rate of enzyme action (i.e., they exhibit some activity).
• Option D: At pH 6, intestinal protease has a higher relative rate of enzyme action than gastric protease.

• Option A: From the graph (and general knowledge), not all enzymes work best at neutral pH. For example, gastric protease has an optimal pH in the acidic range.
• Option B: Adding more acid (changing pH) affects the rate of enzyme activity as seen in the graph (enzyme activity changes with pH).
• Option C: Enzymes can function in a wide range of pH values (not just 4.0 - 5.5 as shown by the two proteases in the graph).
• Option D: The graph clearly shows that as pH changes, the relative rate of enzyme action (activity of the enzyme) changes. So, the activity of an enzyme is affected by pH.

Answer:

D. an enzyme

Question 22