Warm-up 9/26 (Enzyme Review)

At high temperatures, the rate of enzyme action decreases because the increased heat......

• neutralizes the acids and bases in the system

• alters the shape of the active site of the enzyme

• increases the concentration of the enzyme

• changes the pH of the system

Which enzyme would you expect to find in bacteria growing in a hot environment?

• Enzyme X

• Enzyme Y

Using the diagram, match the following.

• Active Site

• D

• Enzyme

• A

• Product

• E

• Enzyme Substrate Complex

• C

• Substrate

• B

Tags

NGSS.HS-LS1-6

NGSS.HS-PS1-2

Enzymes are capable of increasing the rate of a chemical reaction within a living cell. Enzymes accomplish this through which of the following means?

• reducing the number of products

• reducing the activation energy

• increasing the temperature of the cell

• increasing the concentration of reactants

Answer explanation

Activation energy is the energy the reaction needs to get going. Usually it is quite high, and that is why some reactions take a very long time to get going if they get going at all.

Enzymes LOWER the ACTIVATION ENERGY of a reaction, hence speeding it up!

Tags

NGSS.HS-PS1-4

The graph shows how enzymes affect reactions in cells. Which statement best summarizes the information shown in the graph?

• Enzymes increase the energy of the reactants.

• Enzymes decrease the energy level of the products.

• Enzyme decrease the activation energy of the reaction.

• Enzymes reverse the direction of the reaction.

Answer explanation

The graph clearly shows the reaction goes quicker when the enzyme is present and the activation energy is lowered.

Tags

NGSS.HS-PS1-4

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 increases as pH increases 5.0 to 9.0

• The enzyme’s activity is greater around pH of 8.0 .

Answer explanation

Remember, OPTIMUM is the usually the highest point on the graph and shows the 'best' value.

Which statement best describes the enzyme represented in the graphs below?

• This enzyme works best at a temperature of 35°C and a pH of 8

• This enzyme works best at a temperature of 50°C and a pH of 12

• Temperature and pH have no influence on the activity of this enzyme

• This enzyme works best at a temperature above 50°C and a pH above 12

Answer explanation

For this question you are looking for TWO OPTIMUM values, one for temperature and one for pH.

Tags

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. Pepsin is an example of 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.

In living cells, enzymes act as catalysts, which may reduce the amount of activation energy required for a chemical reaction to occur. In the graphs below, pathway x is a solid line representing the uncatalyzed reaction (without enzyme). The dotted line shows the catalyzed reaction (with enzyme). Which graph best illustrates the changes in a reaction when the catalyst reduces the amount of energy required?

• 
• 
• 
• 

Tags

NGSS.HS-PS1-4

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