Thermodynamics, Bioenergetics and Biochemical Oxidation

A comprehensive set of flashcards covering thermodynamics, bioenergetics, and biochemical oxidation concepts, with a focus on core terms, principles, and relationships in biochemical energetics.

What is thermodynamics?

The study of heat in motion.

What does the first law of thermodynamics state?

Energy can neither be created nor destroyed, only transformed and transferred.

What is a biological system?

A system that involves constant release and exchange of heat during metabolic processes.

What is free energy?

The amount of energy required to do work in standard conditions, also referred to as Gibbs free energy.

What does the second law of thermodynamics state?

All spontaneous processes increase the entropy of the universe.

Define entropy.

A measure of disorder or randomness in a system.

What is enthalpy?

The heat content of a system.

What are the three types of thermodynamic systems?

Open system, closed system, isolated system.

Give an example of an intensive property.

Temperature.

What occurs during a coupled reaction?

Energy is exchanged from one step to another, combining exergonic and endergonic reactions.

What is a steady state in a biological system?

A condition where equilibrium is not attained but maintained for metabolic processes.

What does Gibbs free energy equation represent?

G = H - TS, where G is free energy, H is enthalpy, T is temperature and S is entropy.

How is ATP generated?

Through substrate-level phosphorylation and oxidative phosphorylation.

What is the significance of high-energy bonds?

They drive metabolic processes by releasing high amounts of energy upon hydrolysis.

Name two types of energy compounds mentioned.

High energy compounds and low energy compounds.

What indicates a spontaneous reaction based on Gibbs free energy?

A negative value of G.

What happens to the system when the entropy increases?

The value of the Gibbs energy decreases.

Define coupled reactions in metabolism.

Sequentially arranged metabolic processes where energy is transferred between steps.

Identify the energy forms used in biological systems.

Free energy, mechanical energy, light energy, heat energy, and chemical energy.

What role do redox potentials play in metabolic reactions?

They indicate the ability of substrates to receive or donate electrons.

What is a redox reaction?

A reaction that involves the transfer of electrons between two species.

Differentiate between oxidized and reduced forms in redox potential.

Oxidized forms lose electrons while reduced forms gain electrons.

What factors can affect the stability of high-energy compounds?

Charge separation, stabilization during hydrolysis, and hybridization.

How does temperature influence entropy?

Higher temperature tends to increase entropy when internal heat generation is high.

What is the equilibrium expression for a reaction?

Keq = [C]c [D]d / [A]a [B]b.

How does the Gibbs free energy change relate to the equilibrium constant?

A slight change in free energy can cause a large change in the equilibrium constant.

What happens in a closed system?

Mass can transfer, but no heat transfer occurs.

Describe the term 'high-energy compounds.'

Compounds that yield significant energy when their high-energy bonds are hydrolyzed.

What is an endothermic reaction?

A process that absorbs heat, indicated by a positive enthalpy value.

What constitutes a spontaneous reaction in terms of Gibbs free energy?

When G is negative.

How does the body acquire energy to do work?

From diet and the potential energy in nutrient molecules.

What signifies an exergonic reaction?

A reaction with a negative Gibbs free energy change.

What is bioenergetics?

The study of how energy flows through living systems for survival.

Explain the role of dietary nutrients in thermodynamics.

They provide potential energy that is converted into usable forms for metabolic processes.

What is the relationship between entropic change and spontaneity?

Higher entropy generally favors spontaneity, making reactions more likely to occur.

Why is ATP known as the major energy carrier?

Due to its unique ability to release large amounts of energy easily.

What does the standard free energy change tell us?

It indicates the energy that drives a reaction towards equilibrium.

What role does NAD+ play in biochemical reactions?

It serves as an electron carrier during reduction processes.

What is the significance of the driving force towards equilibrium?

It propels reactions forward until equilibrium is reached.

What is a key characteristic of an open system?

It exchanges both heat and matter with its surroundings.

How is high energy released in metabolic reactions?

By breaking high-energy bonds often found in specific compounds.

Identify one example of a low-energy compound.

Any ATP breakdown product.

Explain the concept of 'steady state' in metabolism.

A condition where all metabolic processes are ongoing without reaching full equilibrium.

How do coupled reactions influence metabolic pathways?

They connect different pathways ensuring that energy transfers can occur efficiently.

What is the main characteristic of an isolated system?

No heat or mass transfer occurs with the surroundings.

In biological systems, what is the purpose of coupled reactions?

To drive essential metabolic processes by linking exergonic and endergonic reactions.

Define a metabolic pathway.

A series of enzymatic reactions that convert substrates into products within a cell.

How does energy transformation occur during biochemical reactions?

Through the breaking and forming of bonds that release and store energy.

What is the Gibbs Free Energy reaction quotient?

The ratio of the products to reactants raised to the power of their respective coefficients.

Identify what happens to reactants during an exergonic reaction.

They are converted into products with the release of energy.

What tools are used to measure thermodynamic properties?

State functions such as Gibbs free energy, enthalpy, and entropy.

Explain what a cell's metabolic rate indicates.

It reflects the speed at which energy transformations occur within cellular activities.

What signifies a non-spontaneous reaction based on Gibbs free energy?

A positive value of G.

Why are fluctuations in temperature relevant to biochemical reactions?

They can affect entropy, energy levels, and overall reaction rates.

How can enthalpy changes indicate the type of reaction?

Positive changes indicate endothermic reactions while negative changes indicate exothermic reactions.

Explain the concept of energy coupling in biological systems.

Linking exergonic processes to endergonic ones to harness energy effectively.

Describe the importance of resonance in high energy compounds.

It helps stabilize the compound during bond breakage, impacting energy release.

How does the concept of free energy relate to the direction of chemical reactions?

It helps predict whether a reaction will proceed spontaneously under given conditions.

What are the implications of an increased degree of disorder in a system?

It generally leads to a decrease in Gibbs free energy and thus promotes spontaneity.

State one reason why ATP is preferred for energy storage in cells.

Its ability to release energy quickly and in manageable amounts.

What properties allow biological systems to adhere to the laws of thermodynamics?

Their ability to exchange energy and matter constantly with the environment.

Explain the energy transformation observed in cellular respiration.

Conversion of chemical energy from nutrients into ATP through metabolic pathways.

How do redox potentials help understand metabolic energy flow?

By highlighting the electron transfer capabilities of various substrates.

Identify one role of FAD in redox reactions.

It serves as an electron carrier, facilitating the reduction process.

What type of reaction requires high temperatures to occur?

Reactions associated with a higher Gibbs free energy (non-spontaneous reactions).