Factors That Affect Enzymes

Factors which affect the rate of enzyme catalysed reaction

Review

Previous Learning

Multiple Choice

Which of these is most likely an enzyme?  

• Sucrose
• Galactose
• Fructose
• Amylase

Multiple Choice

Cells can produce over one thousand different enzymes at a time.  Enzymes are critical to the metabolism of these cells, but why are so many different enzymes needed?

• Cells are completely unable to control what enzymes
  they produce
• The variety of enzymes prevents their actions from being inhibited. 
• The active site of an enzyme can only bind to a specific substrate.
• The products of a reaction are always converted into new enzymes.

Multiple Choice

What happens when enzymes are heated to a high temperature?

• The enzymes die.
• The shapes of the enzyme are altered or denatured
• The enzymes' amino acid sequence changes.
• The enzymes remain the same

Multiple Choice

Most enzymes are composed of .....

• Lipids

• Carbohydrates

• Proteins

• Nucleic Acids

Multiple Choice

A ______________ is a substance that increases the rate of a reaction without being used up during the reaction.

• catalyst

• product

• reactant

• solute

Multiple Choice

In the reaction:

Maltose + water ---> glucose + glucose. What is the enzyme involved in this reaction?

• Maltase

• Pepsin

• Lipase

• Catalase

Multiple Select

List three factors that affect the rate of a reaction

• temperature

• concentration

• surface area

• volume

Multiple Choice

Collision theory states that....

• reaction rate increases when particles collide more

• reaction rate is not affected by collisions

• reaction rate increases as there are fewer collisions

• there is no relationship between collisions and reaction rate.

Factors which affect the rate of the enzyme catalysed reaction

The concentration of the enzyme

• The more concentrated is the enzyme...

• ...the faster the rate of the reaction.

The concentration of the substrate

• The more concentrated the substrate...

• ...the slower the reaction.

The temperature of the reaction

• The closer the temperature to the optimum temperature...

• ...the higher the rate of the reaction.

• The further it is from the optimum temperature...

• ...the slower the rate of the reaction.

The pH of the reaction

• The closer it is to the optimum pH...

• ...the higher the rate of the reaction.

• The further it is to the optimum pH...

• ...the slower the rate of the reaction.

The surface area of the substrate

• The smaller the size of the substrate...

• ...the more the surface area...

• ...the higher the rate of the reaction.

Multiple Choice

Which of the following factors will not speed up a chemical reaction?

• Increasing the temperature of the reaction

• Increasing the particle size of reactants

• Increasing the concentration of reactants

Multiple Choice

Why does a higher temperature increase the rate of a reaction?

• It increases both the frequency collision and energy of reactant particles

• It only increases the frequency of collision

• It only increases the energy of reactant particles

• It reduces the activation energy of the reaction

Multiple Choice

Grains of sugar have a greater _______ than a solid cube of

sugar of the same mass, and therefore will dissolve quicker in water.

• Surface Area

• Catalyst

• Temperature

• Concentration

Multiple Choice

Smaller particle size allows for a _________ surface area to be exposed for the reaction.

• larger

• smaller

• rectangular

• spherical

Multiple Choice

A pupil places 10 g of potato into 1 mol/liter hydrogen peroxide solution.

The potato has a biological catalyst inside it that breaks the hydrogen peroxide down to water and oxygen gas.

The pupil counts 15 bubbles of oxygen given off every minute.

What could she do to the 10 g of potato that would increase the number of bubbles per minute?

• Cook it before the experiment.

• Cut the potato in smaller pieces.

• Use more potato.

• Decrease the temperature of the reaction.

Multiple Choice

A pupil places 10g of potato into 1 mol/l hydrogen peroxide solution.

The potato has a biological catalyst inside it that breaks the hydrogen peroxide down to water and oxygen gas.

What would happen to the number of bubbles per minute if she used a less concentrated hydrogen peroxide solution instead of the original 1 mol/l?

• stay the same

• increase

• decrease

• stop

Multiple Choice

A pupil places 10g of potato into 1 mol/l hydrogen peroxide solution at a temperature of 20°C.

The potato has a biological catalyst inside it that breaks the hydrogen peroxide down to water and oxygen gas.

What would happen to the number of bubbles if the temperature was increased to 30°C?

• increase

• decrease

• stay the same

• stop