8. (a) (i) What is an enzyme? (ii) On what structures in the cytoplasm are enzymes made? (b) Answer the following questions in relation to an investigation that you carried out into the effect of temperature on the rate of activity of an enzyme - Leaving Cert Biology - Question 8 - 2012

Enzymes are synthesized on ribosomes in the cytoplasm. Ribosomes can be found either free-floating in the cytoplasm or attached to the endoplasmic reticulum.

The enzyme used in the investigation was catalase, which is commonly found in many living organisms and catalyzes the decomposition of hydrogen peroxide into water and oxygen.

The substrate used was hydrogen peroxide (H₂O₂), which is the specific molecule that catalase acts upon.

The temperature was varied by placing the reaction mixture in water baths set at different temperatures, allowing for controlled conditions to assess enzyme activity at each specific temperature.

The rate of enzyme activity was measured by observing the amount of oxygen produced over a set period of time, typically by collecting the gas in an inverted graduated cylinder.

The pH was kept constant by using a buffer solution, which maintains a stable pH level throughout the enzyme reaction regardless of the amounts of reactants consumed or products generated.

The results indicated that the enzyme activity increased with temperature up to an optimal point, after which the activity sharply decreased, demonstrating the enzyme's sensitivity to heat and the concept of denaturation.