Experimental Design

Propose experimental designs by which the rate of enzyme function can be measured and studied.

The rate of enzyme function can be measured and studied by having an enzyme catalyze reactions in different temperatures, in different pH, in different concentrations of substrates, etc. to see how the enzyme functions if one variable is changed slightly. These are all variable that impact an enzyme’s productivity, so picking any one of these variables ]or some other variable that impacts enzyme functioning] and modifying it slightly as you measure the change in productivity can help study the rate at which an enzyme functions. Depending on the enzyme and variable used/ manipulated, different equipment will be needed for the experiment. If I were measuring the rate of enzymatic activity in different pH, I would need to add acid or base to an enzyme in it’s natural environment, then measure the change in time, or change in production of the product.

Demented PAC-MAN and Competitive Interactions

Describe how enzyme-mediated reactions can be controlled through competitive and noncompetitive interactions.

The following is a helpful little video that explains competitive and noncompetitive interactions through animation:

Enzymes are Serial Huggers

Describe the relationship between the structure and function of enzymes.

Substrates are reactants that attach to enzymes, and detach as a product of the reactants. The structure of an enzyme dictates what reactants it can help catalyze. When reactants enter and bond with an enzyme, the enzyme will reshape itself slightly around the substrate, to create a more snug hold. This allows the reactants to be in very close proximity, forcing the reaction to run faster.

Traffic Jam on Metabolic Lane

Explain how enzymes accomplish biological catalysis.  Provide examples.

Enzymes are reusable catalysts that speed up metabolic reactions. Without enzymes, metabolic reactions would take so long that an organism would not receive the needed substances fast enough. There would be a build up of reactions waiting to occur because the amount of time and energy needed to reach the activation point wouldn't be available. Imagine having to wait hours for painkillers to kick in when you have a raging headache. Sounds fun! Enzymes speed up chemical reactions by lowering the activation energy needed for products to form. This allows molecules involved in the reaction to absorb more energy in lower temperatures, causing the reaction to again enough energy to form products more quickly. Take a look at the figure below: it shows how substrates and enzymes work to lower the activation energy.

Mastering Biology | Pearson; Campbell Biology

Enzyme Environmental Conditions

Analyze data showing how changes in enzyme structure, substrate concentration, and environmental conditions (pH, temperature, salinity, etc.) affect enzymatic activity - ie. include a graph of each example and predict the effects when one of the parameters is further changed.

Justify and explain your predictions.

Enzymes have ideal states of pH and temperature in which they have optimal enzymatic activity. If an enzyme is placed in an environment in which the pH or temperature is not ideal, the rate at which it functions will be altered. Take a look at the graphs below. If a typical human enzyme was placed in a thermophilic bacteria, the human enzyme would be inactive and possible become denatured. Why? Because the optimal temperature for the enzyme to activate is around 37 degrees, anything past 50 degrees is too high and the enzyme can become damaged because it is not in an environment in which it can survive. Same goes for pH with pepsin and trypsin. They cannot exchange locations and be expected to function because they are only stable and functioning in their own environment.

Mastering Biology | Pearson; Campbell Biology

Energy Coupling Reactions

Explain the key role of ATP in energy coupling reactions. Provide a model showing energy before and after phosphorylation of the reactants.

Energy coupling is the process of using the energy released from exergonic reactions to drive endergonic reactions. ATP is not only a cell’s main source of power, but also responsible for energy coupling reactions. Energy is stored in the bond between the third and second phosphate in ATP, and when this bond is broken by hydrolysis [catabolic reaction], energy is released. This energy could be used to facilitate all sorts of cellular work, such as stimulate a potassium-pump to run[anabolic reaction].

Exergonic and Endergonic Reactions

Compare and contrast Exergonic and Endergonic reactions - include a model of each showing the change in free energy from reactants and products.

Exergonic - Catabolic reactions. They break down substances and require no energy, so they are able to occur spontaneously. The change in free energy in these reactions are negative because the reactions break DOWN to create products.

Endergonic - Anabolic reactions. They build up substances and require energy to do so. As a result, these reactions can only occur when energy is available. The change in free energy in these reactions are positive because reactants work UP to create a product.