Which of the following is NOT true of enzyme regulation?

Which of the following is NOT true of enzyme regulation?

A - An enzyme can be negatively regulated
B - Enzyme regulation ensures control on enzyme function
C - An enzyme can be positively regulated
D - All enzymes are regulated by the same inhibitors
E - An enzyme can be both positively and negatively regulated


Answer: D - All enzymes are regulated by the same inhibitors

A non-substrate molecule binds to an enzyme. Now the enzyme is able to bind its substrate when it previously could not. What has likely occurred?

A non-substrate molecule binds to an enzyme. Now the enzyme is able to bind its substrate when it previously could not. What has likely occurred?

A - An activator is bound to the substrate
B - A competitive inhibitor is bound to the enzyme
C - The active site has changed shape
D - The reaction has been negatively regulated
E - A noncompetitive inhibitor is bound to the enzyme


Answer: C - The active site has changed shape

Competitive inhibition involves an inhibitor.

Competitive inhibition involves an inhibitor.

A - Increasing enzyme reaction rates
B - Binding to the active site
C - Inhibiting enzyme function
D - Recognizing a substrate
E - Binding away from the location


Answer: B - Binding to the active site

Cellular respiration includes a step that converts pyruvate into Acetyl coA. Acetyl coA is also known as Coenzyme A. This implies that Acetyl coA.

Cellular respiration includes a step that converts pyruvate into Acetyl coA. Acetyl coA is also known as Coenzyme A. This implies that Acetyl coA.

A - Helps and enzyme perform a function
B - Is bound tightly to the enzyme
C - Is one of the enzymes performing the function
D - Is a metal ion


Answer: A - Helps and enzyme perform a function

A coenzyme is differentiated from the broader class of cofactors because it is.

A coenzyme is differentiated from the broader class of cofactors because it is.

A - All of these
B - Metal
C - Inorganic
D - Organic


Answer: D - Organic

Which of the following is NOT true of a noncompetitive inhibitor?

Which of the following is NOT true of a noncompetitive inhibitor?

A - The enzyme active site can change shape
B - The reaction may be completely prevented
C - It is possible for a substrate to still bind to its substrate
D - The enzyme may proceed slowly
E - The inhibitor can bind to the active site


Answer: E - The inhibitor can bind to the active site

An activator could have the following effect on an enzyme.

An activator could have the following effect on an enzyme.

A - Increase in inhibitor binding
B - Inhibition of substrate binding
C - Decrease in enzyme function
D - Increase in number of substrates that can simultaneously bind to one enzyme
E - Increase of reaction rates


Answer: E - Increase of reaction rates

Iron binds tightly to the heme group in the protein hemoglobin. What type(s) of helper molecule would this be considered?

Iron binds tightly to the heme group in the protein hemoglobin. What type(s) of helper molecule would this be considered?

A - A coenzyme, cofactor, and prosthetic group
B - Only a coenzyme
C - A cofactor and a coenzyme
D - Only a cofactor
E - A prosthetic group and cofactor


Answer: E - A prosthetic group and cofactor

What type of bond is often formed between prosthetic groups and proteins?

What type of bond is often formed between prosthetic groups and proteins?

A - Metal
B - Hydrogen
C - Polypeptide
D - Covalent
E - Amino acid


Answer: D - Covalent

Many coenzymes are derived from.

Many coenzymes are derived from.

A - Vitamins
B - Any of these
C - Inorganic molecules
D - Metals


Answer: A - Vitamins

Which of the following would likely NOT increase a reaction rate of an enzyme in your mouth that was not yet at optimal conditions?

Which of the following would likely NOT increase a reaction rate of an enzyme in your mouth that was not yet at optimal conditions?

A - Extremely high temperature
B - Neutral pH
C - Slight increase in temperature
D - More enzyme
E - More substrate


Answer: A - Extremely high temperature

An increase in temperature.

An increase in temperature.

A - Provides optimal OH- and H+ concentration
B - Increases the likelihood an enzyme and substrate will collide
C - Changes the shape of the substrate
D - Increase substrate concentration
E - Provides shape to an enzyme


Answer: B - Increases the likelihood an enzyme and substrate will collide

The following conditions can denature an enzyme.

The following conditions can denature an enzyme.

A - Increased substrate concentration, extreme temperature, extreme pH
B - Extreme temperature and extreme pH
C - Extreme temperature only
D - Extreme pH and increased substrate concentration
E - Increased substrate concentration only


Answer: B - Extreme temperature and extreme pH

The change in free energy of a reaction is

The change in free energy of a reaction is

A - Slower with the help of an enzyme
B - Faster with the help of an enzyme
C - Unchanged with the help of an enzyme
D - Decreased with the help of an enzyme
E - Increased with the help of an enzym


Answer: C - Unchanged with the help of an enzyme

Pepsin works optimally in your stomach due to its.

Pepsin works optimally in your stomach due to its.

A - Acidic pH
B - Low temperature
C - Basic pH
D - High temperature
E - Substrate concentration


Answer: A - Acidic pH

An enzyme will reach its saturation point.

An enzyme will reach its saturation point.

A - When it has denatured
B - When it is at an optimum temperature
C - When no more substrates are available
D - When it is at an optimum pH
E - When no more enzyme is available to work on substrates


Answer: E - When no more enzyme is available to work on substrates

Which of the following is NOT true of lactase?

Which of the following is NOT true of lactase?

A - Lactose binds in its active site
B - It is an enzyme
C - It forms an enzyme-substrate complex with lactose
D - It does not change the free energy from the breakdown of lactose
E - It can break down different sugar substrates besides lactose


Answer: E - It can break down different sugar substrates besides lactose

Which of the following is TRUE about enzymes?

Which of the following is TRUE about enzymes?

A - Enzymes increase the temperature of a chemical reaction
B - Enzymes raise the activation energy of a chemical reaction
C - Enzymes leave the activation energy of a chemical reaction unchanged
D - Enzymes lower the activation energy of a chemical reaction
E - Enzymes decrease the rate of a chemical reaction


Answer: D - Enzymes lower the activation energy of a chemical reaction

The location of substrate binding is called the

The location of substrate binding is called the

A - Enzyme-Substrate complex
B - Induced fit
C - Catalyst
D - Active site
E - Lactose


Answer: D - Active site

What is induced fit?

What is induced fit?

A - A change in enzyme shape to bind to a substrate
B - The rise in the free energy in a cell
C - A chemical reaction in a cell
D - The barrier to a chemical reaction in the cell


Answer: A - A change in enzyme shape to bind to a substrate