Final answer:
Lowering the temperature below the optimal level affects the shape of enzymes, reducing the reaction rate.
Step-by-step explanation:
Enzymes are proteins that catalyze chemical reactions in living organisms. The shape of an enzyme is crucial for its function. Enzymes have active sites that bind with specific substrates. When the temperature is lowered below the optimal temperature, the enzyme's shape is affected, leading to a decrease in reaction rate. This is because low temperatures can cause the enzyme to become less flexible, making it harder for the enzyme and substrate to collide and form the enzyme-substrate complex.
Learn more about enzyme shape and collisions