Question

12)using graph 1, explain how enzymes work. include the term activation energy and compare the two curves, explaining which is with the enzyme.
13)using graph 2, explain how temperature affects enzyme activity. use the word denature.
14)using graph 3, explain how ph affects enzyme activity. relate to temperature effects.

Explanation:

Question 12

Enzymes are biological catalysts. Activation energy is the energy needed to start a chemical reaction. In a typical graph (like an energy - reaction progress graph), there are two curves: one for the reaction without an enzyme and one with an enzyme. The curve with the enzyme has a lower peak (activation energy) than the curve without the enzyme. This is because enzymes lower the activation energy of a reaction. So, the reaction with the enzyme proceeds faster as less energy is required to start it. The curve with the lower activation energy (lower peak) represents the reaction with the enzyme, while the higher - peaked curve is the reaction without the enzyme.

Enzyme activity is affected by temperature. At low temperatures, enzyme activity is low because molecules have less kinetic energy, so enzyme - substrate collisions are rare. As temperature increases towards an optimal temperature, enzyme activity increases because the increased kinetic energy leads to more frequent and energetic enzyme - substrate collisions. Beyond the optimal temperature, high temperatures cause the enzyme's active site to denature (lose its specific three - dimensional shape, including the active site structure). When the active site denatures, the enzyme loses its catalytic activity, and enzyme activity decreases sharply. So, the graph (usually a curve) shows an increase in activity with temperature up to the optimal point, then a decrease as the enzyme denatures at higher temperatures.

Enzyme activity is also affected by pH. Each enzyme has an optimal pH (e.g., pepsin in the stomach has an optimal pH around 2, while many enzymes in the cytoplasm have an optimal pH around 7). At pH values below or above the optimal pH, the enzyme's active site can be altered. Similar to the effect of extreme temperature, extreme pH (too acidic or too basic) can cause the enzyme to denature (change its three - dimensional structure, including the active site). When the active site is altered or the enzyme denatures, enzyme activity decreases. Like temperature, pH has an optimal range; outside of this range, enzyme activity declines, often due to denaturation (similar to how extreme temperatures cause denaturation and reduced activity).

Answer:

Enzymes act as catalysts by lowering the activation energy of a chemical reaction. In a reaction - energy graph, the curve with the enzyme has a lower activation energy (shorter energy “hill” to climb) than the curve without the enzyme. The curve with the lower activation energy is the one with the enzyme, as enzymes reduce the energy needed to initiate the reaction, speeding it up.

Question 13