Videos and Notes which teach you everything you need to know
Flash Mode: Quick Videos for cramming
Revision Mode: Self Paced Videos with Full Notes
Enzymes
Role and Function of Enzymes
- Enzymes are BIOLOGICAL CATALYSTS—they speed up reactions without being consumed or altered.
- ENZYMES are produced by living organisms to regulate chemical reactions.
Structure of Enzymes
- Enzymes are large PROTEINS composed of amino acid chains.
- These proteins fold into UNIQUE SHAPES that are crucial for their function.
How Enzymes Work
Lock and Key Mechanism
- Each enzyme has an ACTIVE SITE with a shape that fits substances known as SUBSTRATES.
- Enzymes are SPECIFIC which means one type of enzyme will only fit one type of substrate.
- When the substrate binds to the active site, it BREAKS UP to form the products
- This specificity means that enzymes catalyse one particular reaction, ensuring precision in biological processes.
- The concept of the 'LOCK AND KEY' model explains this specificity, although the more accurate 'INDUCED FIT' model acknowledges that the enzyme's active site changes slightly to secure the substrate.
Factors Affecting Enzyme Activity
Temperature
- As you increase the temperature, the rate at which the enzyme controlled reactions occur also increase up to a certain point.
- This is because the enzyme and substrates move around faster meaning there are MORE COLLISIONS per second.
- The rate is the fastest at the OPTIMUM TEMPERATURE.
- As the temperature increases past the optimum, the rate DECREASES. This is because the enzymes DENATURE causing the active site to change shape.
pH
- All enzymes have an OPTIMUM pH that they work the best in
- As the pH increases or decreases from the optimum, the rate of reaction DECREASES. This is because enzymes DENATURE causing the active site to change shape.
- Most enzymes in the human body have an optimum pH of 7, but there are some which have different ones.
- The enzyme PEPSIN, for instance, works best in acidic conditions (pH 2) found in the stomach, which shows the importance of the optimum pH for enzyme activity.
Enzymes
Role and Function of Enzymes
- Enzymes are BIOLOGICAL CATALYSTS—they speed up reactions without being consumed or altered.
- ENZYMES are produced by living organisms to regulate chemical reactions.
Structure of Enzymes
- Enzymes are large PROTEINS composed of amino acid chains.
- These proteins fold into UNIQUE SHAPES that are crucial for their function.
How Enzymes Work
Lock and Key Mechanism
- Each enzyme has an ACTIVE SITE with a shape that fits substances known as SUBSTRATES.
- Enzymes are SPECIFIC which means one type of enzyme will only fit one type of substrate.
- When the substrate binds to the active site, it BREAKS UP to form the products
- This specificity means that enzymes catalyse one particular reaction, ensuring precision in biological processes.
- The concept of the 'LOCK AND KEY' model explains this specificity, although the more accurate 'INDUCED FIT' model acknowledges that the enzyme's active site changes slightly to secure the substrate.
Factors Affecting Enzyme Activity
Temperature
- As you increase the temperature, the rate at which the enzyme controlled reactions occur also increase up to a certain point.
- This is because the enzyme and substrates move around faster meaning there are MORE COLLISIONS per second.
- The rate is the fastest at the OPTIMUM TEMPERATURE.
- As the temperature increases past the optimum, the rate DECREASES. This is because the enzymes DENATURE causing the active site to change shape.
pH
- All enzymes have an OPTIMUM pH that they work the best in
- As the pH increases or decreases from the optimum, the rate of reaction DECREASES. This is because enzymes DENATURE causing the active site to change shape.
- Most enzymes in the human body have an optimum pH of 7, but there are some which have different ones.
- The enzyme PEPSIN, for instance, works best in acidic conditions (pH 2) found in the stomach, which shows the importance of the optimum pH for enzyme activity.
