Enzymes Flashcards
What is the definition of enzymes
Enzymes are:
- Catalysts speeding up chemical reactions without being changed.
- Proteins.
- Biological catalysts produced in living cells.
Importance of Enzymes
Vital to Living Organisms:
- Maintain metabolic reaction rates necessary for life.
- Essential for various biological processes.
Function of Enzymes
Catalysis:
- Speed up chemical reactions.
- Not consumed or altered during the reaction.
What is the role of Metabolic Reactions of enzymes:
-
Role:
- Sustain life by regulating metabolic reactions.
- Without enzymes, metabolic processes would be impractically slow.
Example of an enzyme
Digestive Enzymes:
- Facilitate rapid digestion of meals.
- Without enzymes, digestion could take weeks; with enzymes, it takes hours.
What is the Enzyme Substrate Specificity
Specificity:
- Each enzyme is specific to particular substrates.
- The enzyme’s shape complements its substrate.
When is the product formed
Release:
- The product is formed from the substrate and released.
- Enzyme remains available for further reactions.
Specificity Model of enzyme substrate complex:
Lock and Key Model:
- Describes enzyme-substrate interaction.
- Enzyme’s shape fits the substrate like a key in a lock.
Effect of Temperature on Amylase
Procedure:*
- Starch solution heated to set temperatures.
- Iodine added to spotting tile wells.
- Amylase mixed with starch solution; drops added to iodine.
- Record time for iodine to stop turning blue-black.
Observation:
- Quicker completion indicates faster enzyme activity.
Analysis:
- Experiment repeated at various temperatures.
Effect of pH on Amylase
Setup:
- Iodine drops on tile, test tube labeled with pH.
- Amylase (2cm³) and buffer (1cm³) in test tube.
- Starch solution (2cm³) added, stopwatch started.
- Drops of mixture on iodine every 10 seconds.
Observation:
- Time for iodine to remain orange-brown noted.
Analysis:
- Repeated at different pH values for varied enzyme performance.
Significance
Temperature Impact:*
- Illustrates how amylase activity changes with temperature.
pH Influence:
- Shows the enzyme’s pH sensitivity and optimal working range.
Conclusion:
- Understanding Enzyme Dynamics:
- Both experiments provide insights into factors affecting amylase function.
- Temperature and pH variations impact the enzyme’s efficiency.
Enzyme Action & Specificity: Principle
- Enzymes are specific to one substrate due to the complementary shape of their active site.
- This specificity arises from the unique 3-D shape of the enzyme, known as the lock and key hypothesis.
Enzyme Action & Specificity: Lock and Key Hypothesis:
- Describes the matching shape between the enzyme’s active site and the substrate.
- When substrate enters, it forms an enzyme-substrate complex.
Enzyme Action & Specificity: Reaction Process
- Enzymes and substrates move randomly in solution.
- Collision occurs, forming an enzyme-substrate complex.
- Reaction takes place within the complex, producing products.
- Products leave the active site, and the enzyme remains unchanged, ready for further reactions.
How Enzymes Work
Interaction:
- Enzymes and substrates move randomly.
Formation of Complex:
- Collision results in the formation of an enzyme-substrate complex.
Reaction Occurrence:
- Within the complex, the reaction occurs.
Product Release:
- Products leave the active site, freeing the enzyme for subsequent reactions.
End Result:
- Enzyme remains unchanged, capable of catalyzing additional reactions.
Enzymes & Temperature - Importance of Shape
Key Point:
- Enzymes are proteins with a specific shape, crucial for the active site to accommodate substrates.
Enzymes & Optimum Temperature
Optimal Working Temperature:
- Enzymes operate most efficiently at their optimum temperature; e.g., in the human body, it’s 37⁰C.
Denaturation of Enzymes
Definition:
- Denaturation occurs when high temperatures break the bonds holding the enzyme’s shape.
Denaturation Effect on Substrates: Impact on Substrate Binding:
- Denatured enzymes lose their shape, making it impossible for substrates to fit into the active site.
Irreversibility of Denaturation
Denaturation Outcome:*
- Denaturation is irreversible; once enzymes lose shape, they cannot regain it, leading to a halt in activity.
Effect of Temperature Increase on Enzyme Activity - Part 1
Temperature Influence:
- Increasing temperature up to the optimum enhances enzyme activity.
Effect of Temperature Increase on Enzyme Activity - Part 2
Temperature Impact Explanation:
- More energy at higher temperatures leads to faster molecular movement, increased collisions with substrates, and a faster reaction rate.
Low Temperatures & Enzymes
Low Temperatures Insight:
- Low temperatures don’t denature enzymes but result in slower activity.
Enzymes & pH - Optimum pH
Standard pH Level:
- The general optimum pH for most enzymes is 7.
pH Variations in Enzyme Production
Acidic & Alkaline Conditions:
- Enzymes produced in acidic conditions (e.g., stomach) may have a lower optimum pH (pH 2), while those from alkaline conditions (e.g., duodenum) may have a higher optimum pH (pH 8 or 9).
Flashcard: pH Impact on Enzyme Bonds
Bond Destruction Effect:
- Extreme pH levels can break the bonds within the amino acid chain, altering the protein’s shape, especially the active site.
Active Site Shape Change due to pH: Effect on Active Site
- pH deviations from the optimum can change the active site’s shape, hindering substrate fitting and reducing the enzyme’s activity rate.
Denaturation Risk with pH Extremes
Denaturation Warning:
- Moving significantly away from the optimum pH may lead to denaturation, causing the enzyme to lose its functionality.
Enzyme Denaturation & pH
Denaturation Consequence:
- Enzymes can denature if exposed to pH levels too high or too low, resulting in a complete halt in activity.
