21. Most enzymes work by
A. increasing energy of activation
B. decreasing energy of activation
C. not affecting energy of activation
D. none of the above
22. Which category of enzymes belongs to class 5 in the international classification?
A. Hydrolases
B. Isomerases
C. Oxidoreductases
D. Cyclase
23. Lock and key theory is based on the compatibility of
A. enzyme and substrate
B. enzyme and product
C. enzyme and enzyme-substrate complex
D. enzyme-substrate complex and product
24. When an enzyme is functioning at Vmax, the rate of the reaction is limited by
A. the number of collisions between enzyme and substrate
B. the number of substrate molecules in the reaction
C. the concentration of the substrate
D. the rate at which the enzyme can convert substrate to product
25. The equation for the rate of product formation for simple enzyme reaction is given by (Where rmax , maximum reaction rate, Cs substrate concentration, Cp product concentration ES, CES enzyme-substrate concentration)
A. rp= rmax Cs/(Km+Cs)
B. rp= rmaxCs/(Km+ CES)
C. rp= rmaxCs/(Km+CES)
D. rp= rmaxCs/(Km+Cp)