Enzymes

Question 1

Define enzymes.

Answer 1

A biological catalyst made of proteins that speeds up the rate of chemical reactions within our bodies without being changed or used up. They maintain the speed of all metabolic reactions at a rate that can sustain life.

Question 2

What is enzyme-substrate specificity?

Answer 2

Enzyme substrate specificity is when the shape of a substrate has to be complementary to the active site of an enzyme. Only one type of enzyme fits with a particular substrate.

Question 3

Describe a lock and key diagram.

Answer 3

1. A substrate enters the active site of an enzyme.
2. The enzyme and substrate bind in an enzyme-substrate complex.
3. The substrate is made into different products by way of a chemical reaction, known as an enzyme-products complex.
4. The products leave the active site of the enzyme.

Question 4

Define denaturation

Answer 4

A change in the 3D structure of an enzyme so that the active site is no longer complementary to the substrate. This can occur due to too much heat or the wrong pH.

Question 5

Describe how temperature can affect the activity of an enzyme.

Answer 5

Low temperatures reduce the rate of enzyme activity as they have less kinetic energy to move and come into contact with substrates. Low temperatures, however, do not denature enzymes.
High temperatures cause enzymes to move more because of added kinetic energy. After the optimum heat of the enzyme is surpassed, the proteins in the enzyme twist and reconfigure so as not to accommodate any more substrates. This cannot be reversed. The optimum temperature for enzymes is 37 degrees celsius, and get denatures over 50 degrees celsius.

Question 6

Describe how pH can affect enzyme activity.

Answer 6

Every enzyme has an optimum pH (for example, 2 for pepsin and 7 for amylase). Going above or below the optimum pH denatures the enzyme. This process can be reversed.