أسئلة المحاضرة العاشرة بيو (قبل التعديل)

The amount of enzyme present affects the reaction rate, directly proportional to the enzyme concentration, provided substrate and conditions are constant.

Increasing substrate concentration speeds up the reaction up to a point where the reaction rate hits its maximum (Vmax).

The maximum rate of an enzyme-catalyzed reaction when the enzyme is saturated with substrate.

The substrate concentration at which the reaction rate is half of its maximum (1/2 Vmax).

An enzyme that has a high affinity and needs less substrate concentration to reach Vmax.

An enzyme that has a low affinity, and needs more substrate concentration to reach Vmax.

These factors (coenzymes, ion activators, enzyme inhibitors) and conditions (pH, temperature, time) influence reaction rates.

A biological catalyst that speeds up biochemical reactions.

The temperature at which an enzyme's activity is highest (generally around 37-40°C for human enzymes).

The process by which the enzyme loses its shape and function due to extreme temperature or pH, usually above the optimum temperature or pH range.

Temperature affects reaction rate by increasing initial energy, decreasing activation energy, and increasing molecular collisions.

The specific pH range where an enzyme functions most effectively.

Significant changes in pH can alter enzyme structure causing it to lose its function.

Substances that reduce or stop enzyme activity.

A type of enzyme inhibitor that competes with the substrate for the active site of the enzyme.

A type of enzyme inhibitor that does not directly compete with the substrate. Instead, it binds to a different site on the enzyme and alters its shape.

Enzyme activity is affected by factors such as enzyme concentration, substrate concentration, coenzymes, ion activators, inhibitors, temperature, pH, and time.

Increasing enzyme concentration directly increases the reaction rate, provided there's enough substrate and optimal conditions.

When all enzyme active sites are occupied by substrate, the reaction rate reaches its maximum (Vmax). Adding more substrate won't increase the rate anymore.

The substrate concentration at which the reaction rate is half of its maximum (1/2 Vmax). It reflects the enzyme's affinity for its substrate.

High Km enzymes have low affinity for substrate, requiring higher substrate concentrations to reach Vmax. Low Km enzymes have high affinity, requiring lower substrate concentrations.

Coenzymes help enzymes function by binding to them and participating in the reaction. They are often vitamins or their derivatives.

Each enzyme has an optimal temperature and pH at which it works fastest. Outside of these ranges, enzyme activity decreases.

The ideal temperature for most enzymes, at which they function most efficiently. It's typically around 37-40°C for human enzymes.

Increased temperature increases the rate of reaction initially. But, excessive heat leads to enzyme denaturation and reduced reaction rate.

The specific pH value where an enzyme works best. This varies between enzymes, some prefer acidity, others alkalinity.

Changes in pH, even slightly, can negatively affect enzyme activity. Major pH shifts can cause denaturation.