B.11.B Enzyme Redemption

Amylase is an enzyme that breaks down starch into simple sugars. Students conducted an experiment to test how different pH levels affect amylase activity. Each test tube contained starch and amylase and was incubated at the same temperature for 10 minutes. The amount of sugar produced was measured to determine enzyme activity. Which statement best explains the result of test tube 3?

• The enzyme produced more sugar because the pH was too high.

• The starch did not mix with the enzyme.

• The enzyme was denatured and could not break down starch.

• The enzyme became more active in basic conditions.

During digestion, the enzyme lactase helps break down lactose, a sugar found in milk. Without lactase, lactose remains undigested in the digestive system, causing discomfort. What is the main role of lactase in this biochemical reaction?

• It changes lactose into a completely different molecule unrelated to digestion.

• It raises the body temperature to speed up digestion.

• It lowers the activation energy needed to break down lactose.

• It absorbs lactose so it can’t enter the bloodstream.

A scientist is studying an enzyme that breaks down a sugar molecule. After a genetic mutation, the shape of the enzyme’s active site changes slightly. The enzyme is still present in normal amounts in the cell. Which outcome is most likely due to this mutation?

• The enzyme will begin breaking down a different sugar molecule that it normally does not bind to.

• The enzyme will no longer function because the substrate cannot bind to the altered active site.

• The rate of the reaction will increase because the mutation added energy to the enzyme.

• The enzyme will produce a different product even though it binds to the same substrate

A group of students designs an experiment to test how long a single enzyme molecule can continue breaking down hydrogen peroxide. They observe that the amount of product continues to increase over time, even though no additional enzyme is added. Which statement BEST explains why the reaction continues without adding more enzyme?

• The enzyme is permanently altered after each reaction, but remains active.

• The enzyme is not changed during the reaction and can be reused to break down more substrate.

• The substrate regenerates itself, allowing the enzyme to act again.

• The enzyme releases energy that produces more substrate in the reaction.

What is the object labeled Y?

• Enzyme

• ATP

• Substrate

• Product

Tags

NGSS.HS-LS1-7

Which model best represents the enzyme and substrate after the reaction is complete?

• 
• 
• 
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Tags

B.11.B