Question

Layout Referances Mailings Review View Tell me what you want to do 16 A) Explain the lock-and-key model of enzyme activity The shape of reactant molecules (the key) fits into the active site of an enzyme (the lock). CThe shape of an enzyme (the lock) prevents connection of the reactant molecules. The shape of an enzyme (the key) fits into the active site of reactant molecules (the lock). Enzymes help the reactant molecules (the key) fits into the active site of other reactant molecules (the lock). 16 B) What was incorrect about this model? Fischers original model assumed that enzymes undergo a significant change in shape or conformation when reactant molecules (the key) bind to the active site (the lock). Fischer's original model assumed that enzymes were flexible: in fact, enzymes are rigid and static Fischer's original model assumed that enzymes help substrates collide in a precise onentation. Fischers original model assumed that enzymes were rigid; in fact, enzymes are flexible and dynamic. 400

Answer 1

16 A) The lock-and-key model of enzymatic activity suggests that the shape of the reactant molecule (the key) fits into the active site of an enzyme (the lock). The answer is option A.

16 B) The lock-and-key model by Fischer suggests that the substrate is completely complementary in shape to the active site, so that it fits in perfectly, the way a key fits into a lock. The nature of the active site of the enzyme is rigid but in general enzyme molecules are in a dynamic state, not a static one. The answer is D, Fischer's model assumed that enzymes were rigid; in fact, enzymes are flexible and dynamic.