Enzyme Basics and Specificity

Experiments to find out how changing a factor affects how quickly an enzyme-controlled reaction happens.

The factor you change in an experiment to see its effect on the reaction rate.

The factor that changes in response to the independent variable; the thing you measure.

A graph used to show how the reaction rate changes.

A line drawn on a graph to show the overall trend of the data.

Predicting a value between existing data points on a graph.

Estimating a value beyond the range of existing data points.

Amount of enzyme present in a reaction

A biological catalyst that speeds up chemical reactions without being consumed.

Enzymes have a specific shape (active site) that only fits certain substrates.

The part of an enzyme where the substrate binds, crucial for enzyme function.

An enzyme that works inside the cell.

An enzyme that works outside the cell.

A protein with a 3D spherical shape, many enzymes are this type.

A substance that speeds up a chemical reaction without being consumed.

A series of chemical reactions controlled by enzymes to achieve a specific result or target

A graph showing the results of an enzyme experiment, where the independent variable (e.g., substrate concentration) affects the rate of reaction.

A graph that displays data from various conditions (e.g., different temperatures) on a single graph.

The rate of reaction at the beginning of an experiment (determined by the initial gradient of a graph).

The amount of product created in an experiment, often plotted on the y-axis of an enzyme experiment graph instead of reaction rate.

Scales on the axes of a graph that effectively show all data points.

Clearly labeling the axes of a graph with the variables and their units (e.g., temperature in °C).

A model proposing that the active site of an enzyme has a rigid shape perfectly complementary to the substrate, like a lock and key.

A more refined model that suggests the active site of an enzyme adapts its shape to fit the substrate upon binding, like a glove around a hand.

The Lock & Key model proposes a rigid shape for the active site, while the Induced Fit model suggests the active site can change its shape to accommodate the substrate.

X-ray diffraction allows scientists to visualize molecules in 3D, demonstrating the enzyme's shape change before and after the substrate binds.

The specific pH value at which an enzyme functions most efficiently.

The process where an enzyme's structure is permanently altered, losing its functionality.

The active site is where the substrate binds and the chemical reaction occurs, enabling enzymes to facilitate specific reactions.

Enzymes are not rigid structures: they display movement in response to environmental changes, particularly when interacting with substrates.

Extreme pH levels can disrupt the hydrogen and ionic bonds holding the enzyme's structure together, leading to denaturation.

Enzymes act as biological catalysts, speeding up chemical reactions in living organisms, enabling vital biological processes.

Pepsin, an enzyme in the stomach, has an optimum pH of 2 due to the acidic environment created by hydrochloric acid.

The best environment for an enzyme is determined by its specific optimum pH, reflecting where it naturally functions.

Each enzyme has a specific shape that only fits certain substrates, allowing for precise control of biochemical reactions.

When pH is too high or too low, the enzyme's active site is distorted, hindering its ability to bind to the substrate.

Excess H+ ions (acidic) or OH- ions (basic) disrupt the enzyme's structure by affecting the bonds holding it together.

At extreme pH, the enzyme's structure is completely altered, rendering it incapable of catalyzing any reactions.

Molecules that resemble the substrate and compete for the active site of an enzyme, slowing down or stopping the reaction.

Molecules that bind to a different site on the enzyme, changing the active site's shape and preventing substrate binding.

Inhibitors slow down or stop enzyme-catalyzed reactions by reducing the formation of enzyme-substrate complexes.

Increasing inhibitor concentration leads to a slower reaction rate and eventual complete stoppage of the reaction.

Increasing substrate concentration can overcome the effects of competitive inhibitors by outcompeting them for the active site.

Increasing substrate concentration does not restore the reaction rate in the presence of non-competitive inhibitors, as the active site's shape remains altered.

Competitive inhibitors decrease the initial reaction rate but do not affect the maximal rate. Non-competitive inhibitors decrease both the initial and maximal reaction rates.

Investigate how increasing substrate concentration affects the reaction rate. If the rate increases, it is a competitive inhibitor. If the rate remains low, it is a non-competitive inhibitor.