1.4. Enzymes - Key words

Question 1

Catalyst

Answer 1

Substance that speeds up a reaction without changing the substances produced or being changed itself

Question 2

Enzymes

Answer 2

Proteins that have a very specific shape as a result of their structure. They act as biological catalysts and will only catalyse specific reactions

Question 3

Specificity

Answer 3

Enzymes will only catalyse specific reactions due to their specific structure

Question 4

Anabolic reaction

Answer 4

Reaction that builds up new molecules in a cell

Question 5

Catabolic reaction

Answer 5

Reaction that breaks down substances within a cell

Question 6

Metabolism

Answer 6

Sum of catabolic + anabolic processes in a cell

Question 7

Metabolic chain (pathway)

Answer 7

Series of linked reactions in the metabolism of a cell

Question 8

Intracellular enzymes

Answer 8

Enzymes that catalyse reactions within the cell

Question 9

Extracellular enzymes

Answer 9

Enzymes that catalyse reactions outside of the cell in which they are made

Question 10

Activation energy

Answer 10

Energy needed for a reaction to get started

Question 11

Substrate

Answer 11

Molecule(s) on which the enzyme acts

Question 12

Lock-n-key hypothesis

Answer 12

Substrate fits perfectly in enzyme’s active site creating a complex as a key fits a lock

Question 13

Active site

Answer 13

Area of an enzyme that has a specific shape into which the substrate(s) of a reaction fit

Question 14

Induced-fit hypothesis

Answer 14

Active site is considered to have a more flexible shape. The substrate fits the active site which is modified to form the complex. When products leave the complex the enzyme reverts shape

Question 15

Initial rate of reaction

Answer 15

Measure taken to compare the rates of enzyme controlled reactions under different conditions

Question 16

Molecular activity

Answer 16

Number of substrate molecules transformed per minute by a single enzyme molecule

Question 17

Temperature coefficient (Q10)

Answer 17

Measure of the effect of temperature on the rate of a reaction

Question 18

Enzyme inhibitors

Answer 18

Substances that slow down/stop enzymes from working

Question 19

Reversible inhibition

Answer 19

Inhibition of the action of an enzyme by an inhibitor that does not permanently affect the functioning of the enzyme and can be removed from the enzyme. It’s often used to control reaction rates within a cell

Question 20

Irreversible inhibition

Answer 20

Inhibition of the action of an enzyme that is permanent and cannot be undone. Never used within cells to control the rate of reactions

Question 21

Competitive inhibition

Answer 21

Inhibition in which the inhibitor molecule is similar in shape to the substrate molecule and competes with it for the active site of the enzyme

Question 22

Non-competitive inhibition

Answer 22

Inhibition in which the inhibitor does not compete for the active site but forms a complex with the enzyme or enzyme/substrate complex and changes the shape of the active site so it can no longer catalyse reaction

Question 23

Regulatory enzymes

Answer 23

Enzymes that have a site separate to the active site where another molecule can bind to have either an activating or inhibitory effect

Question 24

End-product inhibition

Answer 24

Control system in many metabolic pathways in which an enzyme at the beginning of the pathway is inhibited by one of the end products of the reaction