Enzymes

The graph below shows how the activity of an enzyme changes over a range of pH values. Which of the following conclusions can be drawn from this graph?

• The optimum pH of the enzyme is 6.6.
• The optimum pH of the enzyme is 5.8
• The enzyme’s activity continually increases as pH increases from 5.0 to 9.0
• The enzyme’s activity is greater around pH of 8.0 than around pH of 5.0.

The diagram below illustrates a biochemical process that occurs in organisms. What is another name for the substance labeled "catalyst"?

• Enzyme
• inorganic compound
• Hormone
• Antibody

Which of the following best explains why enzymes are necessary for many cellular reactions?

• Enzymes supply the oxygen necessary for the reactions
•  Enzymes change reactants from solid to liquids during the reactions.
• The reactions take up too much space in the cell if the enzymes are missing.
• The reactions are too slow to meet the needs of the cell if enzymes are missing. 

What will most likely happen if an appropriate enzyme is added to a chemical reaction? 

• The reaction rate will increase.
• The equilibrium of the reaction will be maintained. 
• The reaction rate will decrease.
• The reaction will stop. 

Tags

NGSS.HS-PS1-5

The human body maintains a temperature of around 98.6 degrees at all times. Enzymes are involved in almost every chemical reaction in the body. Which of the following describes the connection between these two statements? 

•  Enzymes function best at a specific temperature.
• The body needs to be warm to prevent hypothermia.
• The body is kept relatively warm to prevent too much enzyme action.
•  There is no connection between the two statements. 

Tags

NGSS.HS-LS1-3

NGSS.HS-PS1-5

As food travels through the digestive system, it is exposed to a variety of pH levels. The stomach has a pH of 2 due to the presence of hydrochloride acid (HCl), and the small intestine has a pH ranging from 7 to 9. HCl converts pepsinogen into pepsin, an enzyme that digests proteins in the stomach. Which of the following most likely happens to pepsin as it enters the small intestine?

•  It becomes inactive.
• It begins to replicate.
•  It's shape changes to engulf large proteins.
• It's activity increases to digest more proteins.

What is the relationship between enzymes and activation energy? 

• When an enzyme catalyzes a reaction, it decreases the activation energy of the reaction.
• When an enzyme catalyzes a reaction, it does not affect the activation energy of the reaction.

The graph shows how the activity of an enzyme changes over a range of pH values. Which of the following conclusions can be drawn from this graph?

• pepsin works best at a pH near 2
• pepsin works best at a pH of 9

If the enzyme has a pH ranging from 7 to 9 what effect would a pH of 3 have on the enzyme?
Enzymes work best at an optimal temperature and pH

• make it inactive
• no change

Enzymes interact with the substrate at the 

• active site
• product