Medicose Academy
Viruses/Acellular Life
Total Questions:
Introduction/Characteristics of Enzymes:
- Enzymes are biological catalysts, predominantly proteins, that accelerate chemical reactions in living organisms without being consumed or altered themselves.
- They are highly specific, catalyzing specific reactions based on their three-dimensional structures.
- Enzymes function by lowering the activation energy required for a reaction to occur, thereby increasing the reaction rate.
- Characteristics of enzymes:
- Proteinaceous nature: Most enzymes are proteins, although some RNA molecules also exhibit catalytic activity.
- Specificity: Enzymes exhibit specificity towards substrates, reacting with specific molecules or classes of molecules.
- Efficiency: Enzymes can enhance reaction rates by factors of millions to billions.
- Regulation: Enzyme activity is often regulated by various factors such as temperature, pH, and regulatory molecules.
Mechanism of Action of Enzymes:
- Substrate binding: Enzymes have active sites where substrates bind through specific interactions such as hydrogen bonding, ionic interactions, and hydrophobic interactions.
- Transition state stabilization: Enzymes stabilize the transition state of the reaction, reducing the activation energy required for the reaction to proceed.
- Catalysis: Enzymes facilitate the conversion of substrates into products by lowering the activation energy barrier, allowing the reaction to occur more rapidly.
- Product release: Once the reaction is complete, products are released from the enzyme's active site, and the enzyme is free to catalyze another reaction.
Factors Affecting Rate of Enzyme Action:
- Temperature: Enzyme activity increases with temperature up to an optimal point, beyond which denaturation occurs, leading to loss of enzyme activity.
- pH: Enzymes have optimal pH ranges at which they exhibit maximum activity. Deviations from this pH range can lead to denaturation or alterations in enzyme structure and activity.
- Substrate concentration: Increasing substrate concentration generally increases the rate of enzyme-catalyzed reactions until saturation is reached, after which further increases in substrate concentration have no effect on reaction rate.
- Enzyme concentration: Higher enzyme concentrations typically result in faster reaction rates, as more enzyme molecules are available to catalyze the reaction.
Enzyme Inhibition:
- Competitive inhibition: Inhibitors bind to the active site of the enzyme, competing with the substrate for binding. This type of inhibition can be overcome by increasing substrate concentration.
- Non-competitive inhibition: Inhibitors bind to a site on the enzyme other than the active site, altering the enzyme's conformation and reducing its catalytic activity. Increasing substrate concentration does not overcome this type of inhibition.
- Reversible inhibition: Inhibitory effects can be reversed by removing the inhibitor from the enzyme, allowing normal enzyme activity to resume.
- Irreversible inhibition: Inhibitors bind permanently to the enzyme, usually through covalent bonds, resulting in permanent loss of enzyme activity.
