Chapter 4 Enzymes

Question 1

Activation energy

Answer 1

The minimum amount of energy required for a reaction to happen.

Question 2

Active site

Answer 2

An area within the tertiary structure of the enzyme has a shape that is complementary to the shape of a specific substrate molecule.

Question 3

Amylase

Answer 3

An enzyme that catalyses the extracellular breakdown of starch.

Question 4

Catalase

Answer 4

An enzyme that catalyses the intracellular breakdown of hydrogen peroxide into oxygen and water.

Question 5

Catalase

Answer 5

An enzyme that catalyses the intracellular breakdown of hydrogen peroxide into oxygen and water.

Question 6

Coenzyme

Answer 6

A type of cofactor that is bound loosely to an enzyme with weak interactions.

Question 7

Cofactors

Answer 7

A non-protein molecule that is needed for the effective functioning of an enzyme.

Question 8

Competitive inhibitor

Answer 8

A molecule which binds to the active site of an enzyme and prevents the substrate from binding.

Question 9

Cyanide (CN-)

Answer 9

A metabolic poison which acts as an irreversible inhibitor of cytochrome
oxidase and hence preventing respiration.

Question 10

End-product inhibition

Answer 10

A method of enzyme inhibition where the product of an enzyme controlled reaction can bind to the enzyme and prevent it from working.

Question 11

Enzyme

Answer 11

A biological catalyst used to speed up the rate of biochemical reactions without
being used up or permanently altered.

Question 12

Enzyme-product complex

Answer 12

The temporary complex formed after the enzyme has catalysed
the reaction but before the products have left the active site of the enzyme.

Question 12

Enzyme-product complex

Answer 12

The temporary complex formed after the enzyme has catalysed
the reaction but before the products have left the active site of the enzyme.

Question 13

Enzyme-substrate complex

Answer 13

The temporary complex formed when the substrate binds to
the active site of the enzyme.

Question 14

Extracellular reaction

Answer 14

A reaction that occurs outside of cells

Question 15

Inactive precursor

Answer 15

An inactive form of an enzyme that cannot carry out its function until it is activated.

Question 16

Induced fit hypothesis

Answer 16

A model of enzyme action that describes how once a specific substrate binds to the active site, the enzyme undergoes subtle conformational changes to fit the substrate better.

Question 17

Intracellular reaction

Answer 17

A reaction that occurs within cells.

Question 18

Lock and key hypothesis

Answer 18

A model of enzyme action that describes how the enzyme will only fit a substrate that has the correct complementary shape to the active site

Question 19

Metabolism

Answer 19

The sum of all the chemical reactions taking place in a cell

Question 20

Non-competitive inhibitor

Answer 20

An inhibitor which binds to a different part of an enzyme known as the allosteric site and prevents the enzyme from functioning.

Question 21

Prosthetic group

Answer 21

An inhibitor which binds to a different part of an enzyme known as the allosteric site and prevents the enzyme from functioning.

Question 22

Substrate specificity

Answer 22

The ability of an enzyme to catalyse only a specific reaction or set of reactions which have substrates complementary to the active site of the enzyme.

Question 23

Temperature coefficient (Q10)

Answer 23

A method of calculating an increase in reaction rate after a
10oc temperature increase: Q10=R2/R1

Question 24

Trypsin

Answer 24

An enzyme that catalyses the extracellular breakdown of proteins.