1 What are prosthetic groups? A Organic cofactors that are tightly bound to enzymes B Inorganic ions that are loosely attached C Protein subunits of enzymes D Substrates that bind to enzymes
2 What is a cofactor? A A protein that speeds up a reaction B A non-protein substance required for enzyme activity C A molecule that blocks the active site D A type of substrate
3 What happens to the rate of an enzyme-catalyzed reaction when all active sites are saturated? A It continues to increase linearly B It reaches a maximum and levels off C It decreases sharply D It stops immediately
4 How does a non-competitive inhibitor reduce enzyme activity? A It binds to the active site and blocks the substrate. B It binds to the enzyme at a site other than the active site, changing the shape of the active site. C It increases the temperature of the reaction. D It breaks down the substrate before the enzyme can act.
5 What is the region of an enzyme called where the substrate binds? A Allosteric site B Active site C Prosthetic group D Coenzyme
6 What is the effect of pH on enzyme activity? A Enzymes work best at any pH B Each enzyme has an optimum pH C pH has no effect on enzymes D Enzymes are permanently activated by extreme pH
7 Which factor can cause thermal denaturation of an enzyme? A Very low temperature B Optimum pH C High temperature D Low substrate concentration
8 What is the effect of increasing substrate concentration on the rate of an enzyme-controlled reaction, assuming excess enzyme? A The rate increases indefinitely B The rate decreases C The rate increases until all active sites are saturated, then remains constant D The rate remains unchanged
9 Which of the following is an industrial application of enzymes in detergents? A Breaking down starch stains B Breaking down protein stains C Breaking down lipid stains D All of the above
10 At low substrate concentration, the rate of an enzyme-catalyzed reaction is directly proportional to: A Enzyme concentration B Substrate concentration C Temperature D pH
11 Which of the following is true about intracellular enzymes? A They function outside the cell B They function inside the cell C They are always secreted D They are inactive at body temperature
12 In the paper industry, enzymes are used to: A Bleach paper B Break down starch to improve paper quality C Increase the strength of paper D Color the paper
13 Which statement about enzyme specificity is correct? A One enzyme can catalyze many different types of reactions. B Enzymes are specific to their substrates due to the shape of the active site. C Enzymes are non-specific and work on any substrate. D Enzyme specificity depends on the temperature.
14 Which model explains enzyme action by stating that the active site is flexible and adjusts to fit the substrate? A Lock and Key Model B Induced Fit Model C Fluid Mosaic Model D Saturation Model
15 In competitive inhibition, how does the inhibitor affect the enzyme? A It binds to the allosteric site and changes the active site shape B It binds to the active site and blocks the substrate C It denatures the enzyme permanently D It increases the enzyme's affinity for the substrate
16 In competitive inhibition, the inhibitor: A Binds to the allosteric site B Has a shape similar to the substrate C Permanently denatures the enzyme D Increases the active site's affinity for substrate
17 Why is the induced fit model considered more accurate than the lock and key model? A It shows that the active site is rigid B It shows that the active site changes shape to fit the substrate C It shows that enzymes are not specific D It shows that substrates change shape to fit the enzyme
19 In non-competitive inhibition, the inhibitor binds to: A the active site B the substrate C an allosteric site D the product
20 The lock and key model of enzyme action was proposed by: A Daniel Koshland B Emil Fischer C Louis Pasteur D Charles Darwin
21 What is a metabolic pathway? A A single enzyme-catalyzed reaction B A series of enzyme-controlled reactions in a cell C The movement of substances across a membrane D The breakdown of glucose without enzymes
22 What is the active site of an enzyme? A A region where the substrate binds and undergoes a chemical reaction B The entire surface of the enzyme C A site where inhibitors always bind D A site that is not involved in catalysis
23 Which of the following is an industrial application of enzymes in the food industry? A Use of amylase in bread making B Use of catalase in paper production C Use of lipase in detergents D Use of protease in DNA replication
24 Enzymes are best described as: A Lipids that store energy B Proteins that speed up chemical reactions C Carbohydrates that provide structural support D Nucleic acids that carry genetic information
25 Which of the following is an organic cofactor that is loosely attached to an enzyme? A Zinc ions B Coenzyme C Prosthetic group D Substrate