Role of ATP

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In a biochemical reaction, what does it mean if ΔG is positive?

The system is at equilibrium

The reaction proceeds only if free energy can be gained (correct)

The reaction occurs spontaneously

There is little or no tendency for a reaction to occur

If ΔG is zero in a system, what does it imply?

The system is highly unstable

The system is at equilibrium and no net change takes place (correct)

The system is endergonic

The system is undergoing a rapid reaction

What is the standard free energy change at a standard state with a pH of 7.0?

$ΔG$

$ΔG_{standard}$

$ΔG0$

$ΔG0′$ (correct)

How do vital processes such as synthetic reactions and active transport obtain energy?

By coupling to oxidative reactions Signup and view all the answers

Why are the terms 'exergonic' and 'endergonic' preferred over 'exothermic' and 'endothermic' in biochemical contexts?

To indicate loss or gain of energy in any form, not just heat Signup and view all the answers

What happens when the magnitude of ΔG in a system is great?

The system is stable with little or no tendency for a reaction to occur Signup and view all the answers

What does the second law of thermodynamics state?

The total entropy of a system must increase if a process is to occur spontaneously. Signup and view all the answers

How is entropy defined?

The total disorder of a system. Signup and view all the answers

In biochemical reactions, what does ΔG represent?

Change in free energy Signup and view all the answers

If ΔG is negative, what can be said about the reaction?

It proceeds spontaneously with loss of free energy. Signup and view all the answers

What happens if ΔG is both negative and of great magnitude for a reaction?

The reaction goes virtually to completion and is essentially irreversible. Signup and view all the answers

What is the relationship between ΔH, ΔE, and ΔS in biochemical reactions?

ΔH ≈ ΔE which is approximately equal to ΔS Signup and view all the answers

What is the role of the high-energy compound denoted as ~Ⓔ in the living cell?

Serves as a transducer of energy from exergonic reactions to endergonic reactions Signup and view all the answers

Which compound is identified as the principal high-energy intermediate in the living cell?

Adenosine triphosphate (ATP) Signup and view all the answers

What is the source of free energy for autotrophic organisms?

Sunlight Signup and view all the answers

What distinguishes heterotrophic organisms in terms of obtaining free energy?

They breakdown complex organic molecules Signup and view all the answers

In what process is ATP crucial for maintaining living processes?

Biosynthesis Signup and view all the answers

How does the high-energy compound ~Ⓔ facilitate energy transfer within the living cell?

Transduces energy from exergonic reactions to endergonic reactions Signup and view all the answers

What is the role of ATP in biochemical reactions?

Promoting thermodynamically unfavorable reactions Signup and view all the answers

Which enzyme interconverts adenine nucleotides to facilitate high-energy phosphate usage and AMP recovery?

Adenylyl Kinase (Myokinase) Signup and view all the answers

What happens when ATP becomes depleted in a cell?

AMP concentration increases Signup and view all the answers

In a reaction catalyzed by hexokinase, what allows the irreversible phosphorylation of glucose to proceed?

High-energy phosphate in ADP Signup and view all the answers

What is the impact of coupling an exergonic reaction with an endergonic one?

The overall reaction becomes more favorable Signup and view all the answers

Which reaction is more likely to be irreversible under physiological conditions?

$Glucose + P1 \rightarrow Glucose 6- phosphate$ Signup and view all the answers

What role does ATP play in organisms?

Mediating the transference of free energy from exergonic to endergonic processes Signup and view all the answers

Which components make up ATP?

Adenine, ribose, and three phosphate groups Signup and view all the answers

What is the bioenergetic significance of the free energy of hydrolysis of ATP?

It helps estimate the comparative tendency of phosphate groups to transfer to an acceptor Signup and view all the answers

What characterizes low-energy phosphates in terms of their G0' values?

Their values are smaller than that of ATP Signup and view all the answers

How do high-energy phosphates compare to ATP in terms of their G0' values?

Their G0' values are higher than that of ATP Signup and view all the answers

What is the function of ATP in cellular reactions?

To store and transfer energy within the cell Signup and view all the answers

In a coupled exergonic-endergonic system, what is the role of the endergonic process?

It must be a component of the coupled system. Signup and view all the answers

What term is used to describe catabolic reactions in biologic systems?

Catabolism Signup and view all the answers

What characterizes synthetic reactions that build up substances in biologic systems?

Anabolism Signup and view all the answers

How can an exergonic and endergonic reaction be coupled in biologic systems?

By sharing a common obligatory intermediate. Signup and view all the answers

Why is it essential for endergonic processes to be coupled with exergonic ones in biologic systems?

To achieve an overall net exergonic change. Signup and view all the answers

What role does loss of free energy as heat play in the coupling of reactions in biologic systems?

It is crucial for the overall net exergonic change. Signup and view all the answers

When ΔG is positive in a biochemical reaction, what does it indicate?

Free energy can be gained for the reaction to occur Signup and view all the answers

In a biochemical system with a ΔG of zero, what state does the system reach?

Dynamic equilibrium Signup and view all the answers

What is the significance of coupling exergonic and endergonic processes in biochemical reactions?

It leads to the release of free energy Signup and view all the answers

In a biochemical context, what does the term 'exergonic' specifically imply about a process?

Loss of free energy Signup and view all the answers

When reactants are present in concentrations of 1.0 mol/L, what does ΔG0 represent?

The standard free energy change Signup and view all the answers

How is a biochemical system described when the magnitude of ΔG is considerable?

The system is stable with little tendency for reactions to occur Signup and view all the answers

What is the primary role of ATP in living organisms?

Transferring free energy from exergonic to endergonic processes Signup and view all the answers

How do high-energy phosphates, compared to low-energy phosphates, typically relate to the free energy of hydrolysis of ATP?

High-energy phosphates have G0' values higher than ATP Signup and view all the answers

What bioenergetic significance does the free energy of hydrolysis of ATP hold?

It acts as a measure of energy released from the breakdown of ATP Signup and view all the answers

What is a key difference between high-energy and low-energy phosphates?

High-energy phosphates release more energy upon hydrolysis Signup and view all the answers

How does the ΔG0' value for the hydrolysis of the terminal phosphate of ATP relate to other biochemically important phosphates?

It is higher, indicating higher energy transfer potential Signup and view all the answers

Why is ATP considered a crucial molecule for cellular processes?

For transferring free energy between exergonic and endergonic processes Signup and view all the answers

Which enzyme catalyzes the interconversion of adenine nucleotides to facilitate high-energy phosphate usage and AMP recovery?

Adenylyl kinase (Myokinase) Signup and view all the answers

Under physiological conditions, which reaction is more likely to be irreversible due to its high exergonic nature?

Phosphorylation of glucose Signup and view all the answers

What is the bioenergetic significance of AMP increasing in concentration when ATP becomes depleted?

It acts as a metabolic signal to increase the rate of catabolic reactions Signup and view all the answers

Which enzyme is responsible for the irreversible phosphorylation of glucose under physiologic conditions?

Hexokinase Signup and view all the answers

What is the role of ATP in allowing the coupling of thermodynamically unfavorable reactions to favorable ones?

To provide energy for unfavorable reactions Signup and view all the answers

Which compound's interconversion allows the recovery of AMP by rephosphorylation to ADP?

~Ⓔ (AMP) Signup and view all the answers

What is the primary reason for the high free-energy change on hydrolysis of ATP?

Stabilization of the reaction products, especially phosphate, as resonance hybrids Signup and view all the answers

In the context of high-energy compounds, which compound acts as an 'Energy Currency' in the cell?

Adenosine triphosphate (ATP) Signup and view all the answers

What role do thiol esters, acyl carrier protein, and amino acid esters play in cellular processes?

Involved in protein synthesis Signup and view all the answers

Which major energy source participates in the energy conservation or energy capture processes within the cell?

~℗ Signup and view all the answers

What happens at a rapid rate due to the extremely small total ATP/ADP pool within active tissues?

Consumption and regeneration of ATP via an ATP/ADP cycle Signup and view all the answers

How does ADP participate in maintaining energy levels within the cell?

Accepts high-energy phosphate to form ATP Signup and view all the answers

Where does the free energy come from in oxidative phosphorylation in aerobic organisms?

The respiratory chain oxidation using molecular O2 within mitochondria Signup and view all the answers

How many nucleotides are formed as a result of glycolysis converting one molecule of glucose to lactate?

Two Signup and view all the answers

Where is creatine phosphate primarily found as a storage form of high-energy phosphate?

Skeletal muscle, heart, spermatozoa, and brain Signup and view all the answers

What is generated directly at the succinate thiokinase step in the Citric Acid Cycle?

High-energy phosphate Signup and view all the answers

Which compound acts as the 'Energy Currency' of the cell by allowing the coupling of thermodynamically unfavorable reactions to favorable ones?

Creatine phosphate Signup and view all the answers

What allows ATP concentrations to be maintained during rapid energy utilization for muscular contraction?

Phosphagens Signup and view all the answers

Which process involves the transfer of high-energy phosphate between ATP and creatine?

Oxidative phosphorylation Signup and view all the answers

Which enzyme catalyzes the formation of lactate from glucose in glycolysis?

Pyruvate kinase Signup and view all the answers

What is the net amount of ATP generated from glycolysis when converting glucose to lactate?

2 ATP molecules Signup and view all the answers

Where does arginine phosphate primarily occur as a storage form of high-energy phosphate?