Chemical Equilibrium and Reaction Coupling

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What is the primary function of a catalyst in a reaction?

Increase the activation energy

Change the nature of the reaction

Consumed by the reaction

Decrease the activation energy (correct)

Which statement about enzymes is true?

Enzymes increase activation energy

Enzymes are not specific for the reactions they catalyze

Enzymes change the nature of a reaction

Enzymes do not change ΔG for a reaction (correct)

What holds the enzyme-substrate complex together?

Hydrogen bonds, electrical attraction, or hydrophobic interactions (correct)

Covalent bonds only

Ionic interactions only

Van der Waals forces

What happens to enzymes in a reaction?

Not consumed and can act repeatedly Signup and view all the answers

What is the function of the active site in an enzyme?

Specifically bind to a substrate like a lock and key Signup and view all the answers

Which is NOT a property of enzymes?

Change the nature of a reaction Signup and view all the answers

What is the role of enzymes regarding activation energy in reactions?

Lower activation energy barrier Signup and view all the answers

'Induced fit' refers to what process in enzyme-catalyzed reactions?

Enzymes changing shape upon substrate binding Signup and view all the answers

What is the main purpose of metabolic pathways?

To control the sequence of enzymatically-controlled reactions Signup and view all the answers

What is the role of the commitment step in a metabolic pathway?

It is the step that begins the sequence of reactions Signup and view all the answers

What is the purpose of feedback (negative) inhibition in a metabolic pathway?

To shut down the pathway when the final product is abundant Signup and view all the answers

What is the relationship between metabolic pathways and homeostasis?

Regulation of enzymes in metabolic pathways helps maintain homeostasis Signup and view all the answers

What is the key difference between reversible and irreversible enzyme inhibition?

Irreversible inhibition permanently binds to the enzyme, while reversible does not Signup and view all the answers

How are metabolic reactions organized within cells?

Metabolic reactions are organized into interconnected pathways Signup and view all the answers

What is the role of enzymes in metabolic pathways?

Enzymes determine the order of reactions in a pathway Signup and view all the answers

How does feedback inhibition regulate the activity of a metabolic pathway?

Feedback inhibition shuts down the pathway when the final product is abundant Signup and view all the answers

Which of the following statements about enzymes is NOT true?

Enzymes increase the activation energy of a reaction by separating substrates Signup and view all the answers

At the point of saturation, what is the state of the enzyme and substrate?

All enzyme molecules are bound to substrate molecules Signup and view all the answers

What is the primary role of an enzyme's active site?

To bind the substrate(s) and stabilize the transition state Signup and view all the answers

Which of the following statements accurately describes the relationship between enzyme and substrate concentrations?

Substrate concentration is usually much higher than enzyme concentration Signup and view all the answers

How is the efficiency of an enzyme typically measured?

By the rate at which it can convert substrate to product Signup and view all the answers

What is the range of turnover rates for enzymes?

1 to 40 million molecules per second Signup and view all the answers

Which of the following actions is performed by enzymes to facilitate a reaction?

Enzymes orient substrate molecules, bringing together the atoms that will bond Signup and view all the answers

What is the primary function of an enzyme's active site during a reaction?

To provide a template upon which the substrates are brought together in the proper position and orientation to react Signup and view all the answers

Which factor is NOT mentioned as a regulator of enzyme activity in the text?

Pressure Signup and view all the answers

What happens to the noncovalent bonds in an enzyme at high temperatures?

They begin to break, leading to denaturation of the enzyme Signup and view all the answers

What type of inhibitor binds to a site on the enzyme other than the active site?

Non-competitive inhibitor Signup and view all the answers

What is the primary effect of nerve gas on the body?

All of the above Signup and view all the answers

Which of the following is NOT a condition that can affect the secondary and tertiary structure of a protein?

Presence of cofactors Signup and view all the answers

What is the term used to describe the loss of a protein's three-dimensional structure and function?

Denaturation Signup and view all the answers

Which type of enzyme inhibitor covalently binds to the active site, permanently inactivating the enzyme?

Irreversible inhibitor Signup and view all the answers

What is the primary function of enzyme inhibitors according to the text?

To regulate metabolic pathways Signup and view all the answers

What is the relationship between the free energy change (G) and the point of equilibrium for a chemical reaction?

The closer the reaction is to equilibrium, the more free energy is released. Signup and view all the answers

What is the purpose of coupling an endergonic reaction (G > 0) to an exergonic reaction (G < 0)?

To make the endergonic reaction occur spontaneously. Signup and view all the answers

What is the relationship between the hydrolysis of ATP and the formation of glucose 6-phosphate in terms of free energy change (G)?

The hydrolysis of ATP has a greater absolute value of G than the formation of glucose 6-phosphate. Signup and view all the answers

What is the role of enzymes in biological reactions?

Enzymes decrease the activation energy of reactions. Signup and view all the answers

What is the relationship between chemical equilibrium and the forward and reverse reactions?

At equilibrium, the forward and reverse reactions are balanced. Signup and view all the answers

What is the relationship between the free energy change (G) and the reversibility of a chemical reaction?

Reactions with G values near zero are characteristic of readily reversible reactions. Signup and view all the answers

What is the purpose of the high-energy phosphate bond in ATP?

The high-energy phosphate bond in ATP is used to activate endergonic processes. Signup and view all the answers

How do enzymes facilitate biologically important reactions?

Enzymes decrease the activation energy of reactions, allowing them to occur more quickly. Signup and view all the answers