AP Bio Unit 3 Cellular Energetics Review

Describe what happens to an enzyme and the reaction when it is denatured.

When enzymes denature they no longer are active and cannot function. The rate of the reaction will be affected, or the reaction will stop.

Identify environmental conditions that would cause an enzyme to denature.

-temperatures that are too high/low -pH outside of the optimal range

Explain why noncompetitive inhibition cannot be overcome by the addition of more substrate.

A more complex pattern, called mixed inhibition, is produced when a single inhibitor both hinders the binding of substrate and decreases the turnover number of the enzyme.

Define allosteric enzymes and their importance

Allosteric enzymes are enzymes where the activity is modified by the noncovalent binding of an allosteric effector at a site other than the active site. This binding mediates conformational changes, altering its catalytic/binding properties. Long-range allostery is important in cell-signaling.

Explain why energy input must exceed energy loss to maintain order and to power cellular processes.

Cellular processes which release energy may be coupled w/ cellular processes that require energy. Loss of energy flow results in death.

Explain how competitive inhibition can be overcome.

Competitive inhibition can be overcome by increasing the substrate concentration. If the substrate predominates in the mixture, it will tend to displace the inhibitor bound to the enzyme

Describe how a change in the pH or temperature in the environment can alter the efficiency of the enzyme activity

Each enzyme has an optimum pH range and changing the pH out of the range will slow enzyme activity. Extreme levels can cause the enzyme to denature; raising temperature generally speeds up a reaction while lowering the temperature slows it down. This is due to the movement of the molecules within the reaction.

Explain how the 1st Law of Thermodynamics is involved with the processes of living organisms (starting with light energy)

Energy from The Sun (light energy), according the the 1st L.o.T, can be transferred to living organisms

Explain how enzymes affect the rate of biological reactions

Enzymes speed up reactions by lowering activation energy

Describe the properties of the active site that must be present in order for a chemical reaction to occur with a substrate

For an enzyme-mediated chemical reaction to occur, the shape and the charge of the substrate must be compatible w/ the active site of the enzyme.

Explain what happens to some of the energy as it is converted from one form to another

In every energy transfer, the potential energy of the final state is less than the potential energy of the initial state.

Describe the impact inhibitors have on reaction rates

Inhibitors reduce the rate of reactions by interfering with the enzyme. Therefore fewer substrate molecules can bind to the enzymes.

Describe how photosynthesis is involved in capturing energy for autotrophs and benefits heterotrophs

Photosynthesis

In an experiment to show the rate of an enzyme catalyzed reaction, explain why denatured enzymes could be used as a negative control.

Since denatured enzymes do not work like normal enzymes, for the experiment they can serve as a negative control to see how the reaction does in a state where and enzyme is not being used to catalyze the reaction.

Describe the 1st Law of Thermodynamics and the concept of free energy

The 1st Law of Thermodynamics states that energy can be transferred and/or transformed but cannot be created or destroyed; free energy is energy in the system available to do work.

Compare and Contrast irreversible and reversible inhibitors in terms of the bonding with the enzyme.

While irreversible inhibitors act more permanently by modifying active sites and slowly dissociating from their target enzyme, reversible inhibitors are characterized by a rapid dissociation from the enzyme and their inhibition can be easily reversed.