Quiz #2: Enzymes

Enzyme B helps in the process of breaking molecule A into molecules C and D. The enzyme becomes denatured, as shown. Which of the following outcomes can be expected?

• The enzyme will be able to convert molecule A into molecules C and D at a faster rate.

• The enzyme will be able to reverse the reaction, combining molecules C and D into molecule A.

• The enzyme will only be able to convert molecule A into molecules C and D a few more times.

• The enzyme will no longer be able to aid in the reaction that breaks molecule A into molecules C and D.

The table below shows four body locations, the digestive enzymes found there, and what molecules the enzymes break down. Enzymes are substances that help stimulate chemical reactions. Use the table to answer any questions that follow.

The enzyme peptidase is responsible for breaking down protein molecules into...

• fatty acids.

• complex sugars.

• amino acids.

• simple sugars

Which graph represents the effect that enzymes have on the activation energy of a chemical reaction?

• 
• 
• 
• 

All enzymes are examples of which type of organic molecule?

• carbohydrates

• lipids

• proteins

• nucleic acids

Which is one role played by saliva in the mouth?

• It helps remove any carbon dioxide present in food.

• It uses enzymes to begin the process of digestion.

• It helps mix food with oxygen before it is swallowed.

• It mixes bacteria that help in digestion with food.

Mr. Johnson is giving a lesson on enzymes in his freshman biology class. Mr. Johnson displays six beakers with either a chemical substrate or chemical enzyme in them. He tells the class that each of the substrates will spontaneously degrade over a set period of time. He asks the class to identify what would happen if he were able to apply the correct enzyme to the correct substrate. Which of the following is the best answer to give Mr. Johnson?

• The reaction would stop immediately.

• The reaction would be maintained.

• The reaction rate would increase.

• The reaction rate would decrease.

The effect of temperature on the relative rate of action of an enzyme is represented in the graph below. What is the optimum temperature for the action of this enzyme?

• 15°C

• 22°C

• 37°C

• 50°C

An enzyme is a special kind of catalyst. How does it work?

• It speeds up specific chemical reactions.

• It breaks down and takes part in chemical reactions to form new products.

• It slows down specific chemical reactions.

• It triggers chemical reactions at any pH or temperature.

A substrate is a substance that is affected by an enzyme. In order for an enzyme to be effective, it must...

• bind to a substrate, transform itself into more of the substrate, and release higher amounts of the substrate as a product.

• bind to a substrate, transform itself and the substrate into products, and cause these products to dissolve.

• bind to a substrate, transform itself into products, and release these products.

• bind to a substrate, transform the substrate into products, and release the products.

An enzyme and four different molecules are shown in the diagram. Which molecules would this enzyme most likely affect in a reaction?

• molecule C, only

• molecule A, only

• molecules A and C

• molecules B and D