Metabolism and Enzymes

Question 1

Anabolic reaction

Answer 1

Build up large molecules from small molecules

Question 2

Catabolic

Answer 2

Break down large molecules

Question 3

Enzymes

Answer 3

3D proteins that have depressions or active sites that catalyse specific chemical reactions without them themselves being altered

Question 4

Features of enzymes (9)

Answer 4

Proteins, Speed up chemical reactions, Not used up in the reaction, Reaction specific, Work under specific conditions, Work by lowering the energy of the reaction, Work on lock-and-key principle, Often work with co-enzymes and co-factors, Can be denatured by heating

Question 5

Activation energy

Answer 5

Energy needed to start a chemical reaction

Question 6

How enzymes work with activation energy

Answer 6

Usually heat provides activation energy but not viable in living organisms, Enzymes lower the activation energy of reactions they catalyse

Question 7

Lock-key model

Answer 7

Analogy put forward to explain the specific action of an enzyme with a single substrate

Question 8

Catabolic enzymes

Answer 8

Enzymes weaken chemical bond resulting in the substrate breaking down into 2 smaller molecules

Question 9

Anabolic enzyme

Answer 9

Enzyme facilitates the formation of bonds between the substrate molecules producing a larger molecule

Question 10

Co-factors and Co-enzymes

Answer 10

Small non-protein molecules that enhance enzyme function by making sure the active site is the right shape

Question 11

Co-factors

Answer 11

Inorganic such as metal ions

Question 12

Co-enzymes

Answer 12

Organic co-factors

Question 13

Example of a Co-factor

Answer 13

DNA polymerase

Question 14

Inhibitors

Answer 14

Molecules that interfere with the enzyme in some way

Question 15

Competitive inhibitor

Answer 15

Has a similar shape to the substrate, Binds on the active site and blocks the substrate from binding so prevents the formation of the enzyme substrate complex

Question 16

Non-competitive inhibitor

Answer 16

Inhibitor binds to another part of the enzyme and changes the shape in such a way to prevent the enzyme product complex forming

Question 17

Example of a competitive inhibitor

Answer 17

Cyanide

Question 18

Example of non-competitive inhibitor

Answer 18

Strychnine

Question 19

Factors that affect enzyme activity

Answer 19

Temperature, Ph, Enzyme concentration, Co-factors

Question 20

Effect of high temperature outside optimal range of enzymes (6)

Answer 20

Enzyme active site denatures, Chemical bonds holding the active site together break, active site changes shape, active site can no longer bind with the substrate, enzyme activity decreases or stops, no products form

Question 21

As enzyme concentration increases

Answer 21

rate of reaction increases assuming there is a sufficient substrate

Question 22

As substrate concentration increases

Answer 22

Increases reaction rate initially but then the enzyme site becomes saturated