Enzyme Basics and Factors Affecting Their Activity
Enzymes are specialized proteins that function as biological catalysts, accelerating chemical reactions in living organisms without being consumed in the process. They play a crucial role in metabolism and are characterized by their ability to be reused.
Definition: Enzymes are proteins that act as biological catalysts, speeding up chemical reactions in living organisms.
The activity of enzymes is significantly influenced by pH and temperature. Each enzyme has an optimum pH at which it functions most effectively. Deviations from this optimal pH can lead to decreased enzyme activity or even denaturation if the pH becomes too extreme.
Highlight: The optimum pH is the pH level at which an enzyme works best, a key concept in GCSE Biology AQA curricula.
The lock and key hypothesis explains the specificity of enzyme-substrate interactions. This model suggests that the active site of an enzyme is shaped to fit only specific substrates, much like a lock fits only a specific key.
Temperature also plays a crucial role in enzyme activity. Generally, an increase in temperature leads to increased enzyme activity up to an optimum point. Beyond this optimum temperature, the enzyme's active site changes shape, leading to denaturation and loss of function.
Example: In GCSE Biology questions, students might be asked to explain how temperature affects enzyme activity, illustrating the relationship between temperature and reaction rate.
Substrate concentration is another factor affecting enzyme activity. As substrate concentration increases, the rate of reaction also increases until all enzyme active sites are occupied, at which point additional substrate has no further effect on the reaction rate.
