Enzyme theory

1. Enzymes will usually react with only one substance. This can be explained by the 'lock and key' theory. If this theory is correct, which of the following substances, represented by P, Q, R and S would be acted on by enzyme A?

• P

• Q

• R

• S

If an enzyme-controlled reaction normally takes place at 10ºC, in general terms how will the reaction be affected by a fall in temperature to 2°C

• The reaction will speed up

• The reaction will slow down

• There is no change to reaction speed

If an enzyme-controlled reaction normally takes place at 10ºC, in general terms how will the reaction be affected by a rise in temperature to 20°C ?

• The reaction will speed up

• The reaction will slow down

• There will be no change to reaction speed

1. The graph shows the rate of an enzyme

reaction at different levels of acidity or

alkalinity (pH). From the graph, what is the

optimum pH for this enzyme?

• pH 2

• pH 7

• pH 10

• none of these

A protein-digesting enzyme when mixed with starch solution would:

• have no action

• produce amino acids

• produce glucose

• digest the starch

All enzymes are produced inside ……...............…

• animals

• cells

• catalysts

• nuclei

Enzymes which do their work outside cells are called ……...............

• extra-cellular

• intra-cellular

• multi-cellular

Enzymes which do their work inside cells are called ……...............….

• extra-cellular

• intra-cellular

• multi-cellular