Topic 3: Enzyme

Question 1

Activation Energy

Answer 1

The energy that must be provided to make a reaction take place; enzymes reduce the activation energy required for a substrate to change into a product.

Question 2

Active Site

Answer 2

An area on an enzyme molecule where the substrate can bind.

Question 3

Allosteric

Answer 3

Other site.

Question 4

ATPase

Answer 4

.

Question 5

Buffer Solution

Answer 5

An aqueous solution consisting a mixture of weak acid and its conjugate base, or vice versa, which has a fixed pH value.

Question 6

Cofactor

Answer 6

Other factor

Question 7

Competitive Inhibition

Answer 7

When a substance reduces the rate of activity of an enzyme by competing with the substrate molecules for the enzyme’s active site; increasing the concentration of the substrate reduces the degree of inhibition.

Question 8

Denaturation

Answer 8

Above a certain temperature, the structure of enzyme molecule vibrate so energetically that some of the bonds holding the enzyme molecule in its precise shape begin to break and the enzyme molecules begin to lose its shape and activity.

Question 9

End-Product Inhibition

Answer 9

End products accumulate within the cell and stop the reaction when the sufficient product is made

Question 10

Enzyme

Answer 10

a protein produced by a living organism that act as a biological catalyst in a specific reaction by reducing activation energy but remains unchanged at the end of the reaction.

Question 11

Enzyme-Substrate Complex

Answer 11

The combined structure in which the substrate is held in place by temporary bonds which form between the substrate and some of the E groups of the enzyme’s amino acids

Question 12

Extracellular

Answer 12

Enzymes that are secreted by cells and catalyse reaction outside the cell.

Question 13

Feedback Mechanism

Answer 13

.

Question 14

Immobilised Enzyme

Answer 14

Enzymes that have been fixed to a surface or within a bead of agar gel

Question 15

Induced Fit Hypothesis

Answer 15

The substrate is complementary shape to the active site of the enzyme but the substrate is not an exact fit.
Enzyme or sometimes the substrate can change its shape in order to ensure a perfect fit for catalysis to occur.

Question 16

Inhibitor

Answer 16

A substance that decrease or stop enzyme activity.

Question 17

Intracellular

Answer 17

Enzymes that operate within cells

Question 18

Irreversible Inhibitor

Answer 18

Inhibitors that damage the enzyme irreversibly leaving them permanently damaged.

Question 19

Lactose

Answer 19

Disaccharides that are found in milk

Question 20

Lock and Key Hypothesis

Answer 20

Enzyme has a particular fixed shape into which the substrate fits perfectly analogous to a key fitting into a lock.

Question 21

Lysozyme

Answer 21

An enzyme that damage the cell wall (made of polysaccharide chains) of bacterias by catalyse the hydrolysis

Question 22

Metabolic Reaction

Answer 22

All the reactions that take place in a living organism

Question 23

Michaelis-Menten constant, km

Answer 23

The substrate concentration at which an enzyme work at half it maximum rate (1/2 Vmax), used as a measure of the efficiency of an enzyme; the lower value of km, the more efficient the enzyme.

Question 24

Non-Competitive Inhibitor

Answer 24

A substance reduce the rate of activity of an enzyme by binding to another site of the enzyme rather than the active site.

Question 25

Optimum

Answer 25

The best possible result; the ideal result

The temperature at which an enzyme catalyse the reaction at the maximum rate

Question 26

pH

Answer 26

A measure of concentration of hydrogen ion in the solution

Question 27

Reversible Inhibitor

Answer 27

Enzyme inhibitors that do not damage the enzyme permanently and do not break the disulphide bond.

Question 28

Saturation

Answer 28

All the active site are bound to substrate to form an enzyme-substrate complex

Question 29

Substrate

Answer 29

Molecules that react in the enzyme catalysis reaction

Question 30

Theoretical Maximum Rate (Velocity), Vmax

Answer 30

The theoretical maximum rate of an enzyme controlled reaction, obtained when all of the active sites are occupied.

Question 31

Turnover Rate of Enzyme

Answer 31

The speed at which an enzyme can convert substrate into a product. A typical enzyme can convert around one thousand substrate molecules into product per second.