Enzymes

Question 1

Enzymes

Answer 1

Protein molecules that control metabolic reactions in living cells. Without enzymes, reactions that occur in cells would be slow or wouldn’t proceed at all.

Enzymes act as biological catalysts, controlling the rate of each step of the complex chemical reactions that take place in cells.

Question 2

Enzyme Equation

Answer 2

A B → C D
Reactants Products

Question 3

Enzyme Reactions

Answer 3

In enzyme-catalysed reactions, the substrate attaches to the shape on the surface of the enzyme (the active site) and forms a substrate–enzyme complex.

The reaction then occurs and the products are released. The enzyme can be re-used for the same reaction.

Question 4

Enzymes are affected by:

Answer 4

TEMPERATURE
Enzyme activity increases as the temperature does until the optimal temperature is reached. With further temperature increases, the enzyme activity decreases and then stops completely when the high temperatures denature the structure of the enzyme.

 PH Each enzyme has an optimum pH at which it functions most efficiently.

 SUBSTRATE CONCENTRATION As the substrate concentration increases, the activity of the enzyme increases until all the enzymes are saturated. After this, further increases in substrate concentration will not lead to increases in enzyme activity.

Question 5

Induced-Fit-Model

Answer 5

Based on the observations that proteins are not rigid. Evidence suggests that the binding of a substrate to the active site of an enzyme makes the enzyme alter its shape slightly, to fit more tightly around the substrate.

Question 6

Homeostasis

Answer 6

When the internal environment is kept within normal limits regardless, of the external environmental conditions.

This includes conditions, such as temperature, pH, gas levels, water and salt concentrations.

This allows the enzyme’s optimal conditions to be met and the body to work efficiently and kept as stable as possible.