Question 1: Define the Lock and Key Theory in the context of enzymes and substrates.

Answer: The Lock and Key Theory suggests that enzymes have specific active sites (the 'lock') that only fit particular substrates (the 'key'), enabling the enzyme to catalyze specific chemical reactions.

Question 2: Explain how the specificity of enzymes is explained by the Lock and Key Theory.

Answer: Enzyme specificity is explained by the fact that only substrates with a particular shape fit into the enzyme's active site, similar to a key fitting into a specific lock.

Question 1: If an enzyme catalyzes 120 reactions per minute under optimal conditions, how many reactions will it catalyze in 30 minutes? Show your calculation.

Answer: Total reactions = 120 reactions/minute × 30 minutes = 3600 reactions.

Question 1: Describe a basic experiment to test the effect of temperature on enzyme activity. Include variables and safety precautions.

Answer: An experiment can involve measuring enzyme activity at different temperatures (e.g., 20°C, 37°C, 60°C). The independent variable is temperature; the dependent variable is enzyme activity (e.g., rate of reaction). Safety precautions include handling hot equipment carefully and avoiding spills. Controls should be used to compare results.

Question 1: In an experiment, enzyme activity was measured at pH 5, 7, and 9. The activity was highest at pH 7 and lower at pH 5 and 9. Explain why enzyme activity varies with pH.

Answer: Enzyme activity varies with pH because enzymes have an optimal pH at which their active sites are properly shaped. Deviations from this pH cause changes in enzyme structure, reducing activity.

Question 1: Describe how the Lock and Key Theory explains the specificity of enzymes for their substrates. Include in your answer how this affects digestion.

Answer: The Lock and Key Theory states that enzymes have specific active sites that match only particular substrate shapes, like a key fitting into a specific lock. This explains why enzymes only catalyze specific reactions. In digestion, this specificity ensures that enzymes break down particular food molecules efficiently, such as amylase breaking down starch into sugars.

Question 2: A student claims that changing the shape of an enzyme's active site will not affect its ability to catalyze reactions. Is this statement correct? Justify your answer.

Answer: No, this statement is incorrect. Changing the shape of the active site can prevent the substrate from fitting properly, reducing or eliminating the enzyme's activity.

Question 1: Explain how knowledge of enzyme specificity is used in the development of pharmaceutical drugs.

Answer: Understanding enzyme specificity allows scientists to design drugs that fit precisely into enzyme active sites, inhibiting or enhancing their activity, which is useful in treating diseases.