Unit 7: Enzymes - Short Questions with Answers
1. What is metabolism?
Metabolism is the sum of all chemical reactions that occur within an organism to sustain life.
2. Differentiate between catabolism and anabolism.
Catabolism breaks down complex molecules into simpler ones,releasing energy (e.g., cellular respiration). Anabolism builds complex molecules from simpler ones, using energy (e.g., protein synthesis).
3. Define an enzyme.
An enzyme is a biological catalyst,usually a protein, that speeds up chemical reactions in living organisms without being used up in the process.
4. What is the active site of an enzyme?
The active site is a specific region on the enzyme's surface where the substrate binds and the chemical reaction occurs.
5. How are enzymes specific to their substrates?
Each enzyme has a unique active site that fits only specific substrate molecules,like a lock and key.
6. What are intracellular and extracellular enzymes?
Intracellular enzymes work inside cells(e.g., enzymes for cellular respiration). Extracellular enzymes work outside cells (e.g., digestive enzymes in the stomach).
7. What are cofactors?
Cofactors are non-protein molecules required by some enzymes to function properly.They include metal ions (inorganic cofactors) and vitamins (organic cofactors).
8. How does temperature affect enzyme activity?
Enzyme activity increases with temperature up to an optimum point(37°C for human enzymes), then decreases as enzymes denature (lose their shape) at high temperatures.
9. What is optimum pH for enzymes?
Optimum pH is the specific pH at which an enzyme works best.Different enzymes have different optimum pH values (e.g., pepsin works best at pH 1.5-2.0, trypsin at pH 7-8).
10. What happens when substrate concentration increases?
Enzyme activity increases with substrate concentration until all active sites are occupied(saturation point), after which activity levels off.
11. What are competitive inhibitors?
Competitive inhibitors are molecules that resemble the substrate and compete for the active site,blocking the substrate from binding.
12. What are non-competitive inhibitors?
Non-competitive inhibitors bind to the enzyme at a site other than the active site,changing the enzyme's shape so the substrate cannot bind.
13. How do enzymes speed up reactions?
Enzymes lower the activation energy required for reactions,making them occur faster without changing the products.
14. What is enzyme denaturation?
Denaturation is when an enzyme loses its three-dimensional shape due to extreme temperature or pH changes,making it non-functional.
15. Why are enzymes important in industries?
Enzymes are used in food processing(cheese making), paper industry, biological detergents, and fermentation industries because they work efficiently at mild conditions.
16. What is the lock and key model?
This model suggests the enzyme's active site has a fixed shape that exactly fits the substrate,like a key fits into a lock.
17. What is the induced fit model?
This model suggests the enzyme's active site changes shape slightly when the substrate binds,creating a better fit for catalysis.
18. Give an example of enzyme specificity.
Amylase enzyme specifically breaks down starch into sugars but does not affect proteins or lipids.
19. How do extreme temperatures inactivate enzymes?
High temperatures break the bonds that maintain the enzyme's shape,causing it to unfold and lose its active site structure.
20. What is the role of enzymes in digestion?
Digestive enzymes break down large food molecules into smaller absorbable units:amylase breaks starch, protease breaks proteins, lipase breaks fats.
