3.6.1

Define enzyme and active site.

1

3.6.2

Explain enzyme–substrate specificity.

3

The lock-and-key model can be used as a basis for the explanation.

Refer to the three-dimensional structure.

The induced-fit model is not expected at SL.

3.6.3

Explain the effects of

temperature,

pH and

substrate concentration on enzyme activity.

3

Aim 7: Enzyme activity could be measured using data loggers such as pressure sensors, pH sensors or colorimeters.

Aim 8: The effects of environmental acid rain could be discussed.

3.6.4

Define denaturation.

1

Denaturation is a structural change in a protein that results in the loss (usually permanent) of its biological properties.

Refer only to heat and pH as agents.

3.6.5

Explain the use of lactase in the production of lactose-free milk.

3

Aim 8: Production of lactose-free milk is an example of an industrial process depending on biological methods (biotechnology). These methods are of huge and increasing economic importance.

Int/TOK: Development of some techniques benefits particular human populations and not others because of the natural variation in human characteristics. Lactose intolerance is found in a high proportion of the human population (for example, in Asia) but more rarely among those of European origin. Sometimes a transfer of biotechnology is needed when techniques are developed in one part of the world that are more applicable in another.