Biology - Enzymes

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. The dotted line shows the catalyzed reaction. Which graph best illustrates the changes in a reaction when the catalyst reduces the amount of energy required?

A catalyst decreases the activation energy needed for a reaction to occur. This allows the reaction to happen faster.

In a chemical reaction, a reactant binds to an enzyme at a region known as the—

Active site

Which of the following BEST explains the role of enzymes in a reaction? A. An enzyme causes an increase in the rate of reaction by binding to a substrate. B.enzyme increases the amount of energy needed to complete the reaction. C.An enzyme binds to a product causing a decrease in the rate of the reaction. D.An enzyme increases the temperature of a reaction so that the reaction can occur faster.

An enzyme causes an increase in the rate of reaction by binding to a substrate.

Which part represents the substrate in the enzyme reaction shown below? A. B. C. D.

B

Substrates temporarily—

Bind to enzymes at specific places called active sites

Enzymes cannot—

Change

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.

Enzymes function best...

In small range of conditions

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? A. It becomes inactive. B. It begins to replicate. C. It's shape changes to engulf large proteins. D. It's activity increases to digest more proteins.

It becomes inactive.

What can disruption cause?

It can prevent enzymes from functioning

What does amylase do?

It helps break down starch to simple sugar.

What do enzymes do?

Lowers the activation energy and speed up the reaction rate

Are enzymes used up or charged during a chemical reaction?

No

The graph below depicts the results of an experiment using 3 different enzymes. What information can be obtained from this graph? A. Salivary amylase can react in a wide range of pH levels. B. Pepsin will increase the rate of reaction at 37 degrees C. C. Pancreatic Lipase is more effective at a higher pH D. Pepsin functions more efficiently at a higher pH

Pancreatic Lipase is more effective at a higher pH

Catalyst

Substances that speed up chemical reactions

What 2 environmental conditions can affect the activity of an enzyme?

Temperature and pH

A neutral pH of 7 and normal organism temperature is needed for a certain enzyme to be effective. What would happen to the enzyme if the pH and/or temperature fluctuate greatly from the norm? A. The activation energy will increase. B. The enzymes hydrogen bonds will break. C. More product will be formed. D. The ideal temperature and pH for the enzyme function will decrease

The enzyme hydrogen bonds will break

Do substrates exactly fit the active sites on enzymes?

Yes

What are the building blocks of proteins?

amino acids

What does an enzyme allow?

it allows only certain reactants to bing to the enzymes

An enzyme speeds up a reaction by

lowering the activation energy

activation energy

the minimum amount of energy required to start a chemical reaction