Enzymes
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Define Enzyme

A globular protein functioning as a biological catalyst

Define active site

The site on surface of enzyme to which substrate or substrates bind

Describe the lock and key model

In the same way as a key fits a lock very precisely, so the substrate fits accurately into the active site of the enzyme molecule. The two molecules form a temporary structure called the enzyme-substrate complex. The products have a different shape from the substrate and so, once formed, they escape from the active site, leaving it free to become attached to another substrate molecule.

List three factors that affect enzyme activity

1.      Temperature

a.      As the temperature increases, the kinetic energy of the substrate and enzyme molecules increases and so they move faster. The faster these molecules move, the more often they collide with one another and the greater the rate of reaction.

b.      As the temperature increases, more atoms vibrate. This breaks the hydrogen bonds, and alters the three-dimensional shape of the enzyme. It thus denatures.

2.      pH

3.      Substrate concentration

a.      The rate of enzyme reaction increases as the concentration of the substrate increases up to a point

Define denaturation

A structural change in a protein (or nucleic acid) that results in a loss (temporary or permanent) of its biological properties

Explain two applications of enzymes in biotechnology

1.      Production of aspartame

2.      Production of semi-synthetic antibiotics

Other Notes in this Category

1. Carbohydrates, Lipids and Proteins
2. DNA Replication
3. DNA Structure
4. Elements of Life
5. Enzymes
6. Genetic Engineering, DNA fingerprinting, gene therapy
7. Transcription and Translation

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