Enzyme Function and ATP Role

Mr. McClain explains the concept of energy coupling in cells, focusing on how exergonic reactions can drive endergonic reactions using ATP. He details the structure of ATP and its hydrolysis, which releases energy. An example of glutamine formation illustrates a coupled reaction. The role of enzymes in lowering activation energy is discussed, emphasizing their efficiency in catalyzing reactions. The impact of environmental factors like temperature and pH on enzyme activity is also covered.

What is the primary role of ATP in cellular reactions?

• To store genetic information

• To act as a structural component

• To shuttle energy between reactions

• To catalyze chemical reactions

Which of the following best describes an exergonic reaction?

• It releases energy

• It has a positive Delta G value

• It is always spontaneous

• It requires energy input

During ATP hydrolysis, what is released along with energy?

• Adenine

• Glucose

• Ribose

• Inorganic phosphate

In the formation of glutamine, what role does ATP play?

• It provides the ammonia

• It acts as a reactant

• It forms a covalent bond with glutamine

• It supplies energy through hydrolysis

What is the net energy change required for a coupled reaction to occur?

• Positive

• Zero

• It varies depending on the reaction

• Negative

How do enzymes affect the activation energy of a reaction?

• They convert it into heat

• They increase it

• They decrease it

• They have no effect

What is the 'induced fit' model in enzymatic reactions?

• Enzymes fit substrates like a lock and key

• Substrates are broken down into smaller molecules

• Enzymes change shape to fit the substrate

• Substrates change shape to fit the enzyme

Which environmental factor can denature enzymes?

• High substrate concentration

• Optimal pH

• Presence of cofactors

• Extreme temperatures

What is the role of cofactors in enzymatic reactions?

• They inhibit enzyme activity

• They assist in enzyme function

• They act as substrates

• They are products of the reaction

How does pH affect enzyme activity?

• It has no effect

• All enzymes work best at neutral pH

• Enzymes function best at a specific pH

• Enzymes are denatured at any pH