1 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.
2 What happens to an enzyme when it is heated above its optimum temperature? A It works faster indefinitely B It becomes denatured C It changes into a substrate D It becomes an inorganic catalyst
3 Which of the following is NOT a characteristic of enzymes? A They are specific to their substrates B They are consumed during the reaction C They are proteins (except some RNA molecules) D They lower the activation energy of a reaction
4 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
5 What is the optimum pH for most human enzymes? A Around pH 2 B Around pH 7 C Around pH 9 D Around pH 14
6 Which of the following is produced during alcoholic fermentation? A Lactic acid and ATP B Ethanol and carbon dioxide C Pyruvic acid and oxygen D Glucose and water
7 Which part of the ATP molecule stores the energy that is released during hydrolysis? A Adenine B Ribose sugar C Phosphate groups D Hydrogen bonds
8 What is the first stage of aerobic respiration? A Krebs cycle B Glycolysis C Electron transport chain D Fermentation
10 Which part of the chloroplast contains chlorophyll? A Stroma B Thylakoid membrane C Outer membrane D Intermembrane space
11 Which of the following is an accessory pigment in photosynthesis? A Chlorophyll-a B Chlorophyll-b C Carotenoids D Both B and C
12 In which part of the chloroplast do the light-dependent reactions of photosynthesis take place? A Stroma B Thylakoid membrane C Outer membrane D Intermembrane space
13 What is the function of a coenzyme? A To break down enzymes B To assist enzymes in catalyzing reactions C To serve as a substrate D To inhibit enzyme activity
14 Which model explains enzyme action by stating that the active site is flexible and changes shape to fit the substrate? A Lock and Key Model B Induced Fit Model C Fluid Mosaic Model D Reflex Arc Model
15 Which part of ATP is responsible for its high-energy bonds? A Adenine B Ribose C Phosphate groups D Deoxyribose
17 Which of the following is an example of a catabolic pathway? A Protein synthesis from amino acids B Photosynthesis C Cellular respiration D DNA replication
18 Which of the following is an example of an extracellular enzyme? A DNA polymerase B Amylase secreted by salivary glands C ATP synthase D Hexokinase
19 Which type of fermentation produces ethanol and carbon dioxide? A Lactic acid fermentation B Alcoholic fermentation C Aerobic respiration D Photosynthesis
21 Which process produces the most ATP in aerobic respiration? A Glycolysis B Krebs cycle C Electron transport chain D Fermentation
23 Which of the following is an example of an intracellular enzyme? A Amylase in saliva B Pepsin in the stomach C Catalase in liver cells D Trypsin in the small intestine
24 Which model of enzyme action was proposed by Emil Fischer? A Induced fit model B Lock and key model C Fluid mosaic model D Saturation model
25 In which organelle does aerobic respiration mainly occur? A Chloroplast B Ribosome C Mitochondrion D Golgi apparatus