Metabolism, Energy, and Enzymes Flashcards

Flashcards based on College Physics Chapter and Biology 2E Chapter 6, focusing on metabolism, energy, and enzymes.

Metabolism

All chemical reactions of a cell or organism.

Metabolic Pathway

A series of biochemical reactions that converts one or more substrates into a final product.

Anabolic

Reactions/pathways that require energy and synthesize larger molecules.

Catabolic

Reactions/pathways that release energy and break down large molecules into smaller molecules.

Bioenergetics

The study of energy flow through a living system.

Energy

The ability to do work.

Kinetic Energy

Energy of objects in motion.

Potential Energy

Energy that objects have the potential to move.

Gibb’s Free Energy (G)

Amount of energy available to do work (aka usable energy).

ΔH

Change in total energy of the system.

T

Temperature in Kelvins.

ΔS

Change in entropy (energy lost to disorder).

Exergonic Reactions

Reactions where energy is released (ΔG is negative).

Spontaneous Reactions

Reactions that are classified as spontaneous reactions because they can occur without the addition of energy

Endergonic Reactions

Reactions that require an input of energy (ΔG is positive).

Activation Energy

Energy required for a reaction to proceed.

Transition State

Unstable state where reactant(s) become contorted and unstable.

Thermodynamics

The study of energy and energy transfer involving physical matter.

First Law of Thermodynamics

The total amount of energy in the universe is constant; energy cannot be created or destroyed.

Second Law of Thermodynamics

The transfer of energy is not completely efficient; some energy is lost in a form that is unusable, such as heat energy, increasing entropy.

Entropy

Increased disorder.

ATP (Adenosine Triphosphate)

The cellular energy currency.

Adenosine

A nucleoside consisting of the nitrogenous base adenine and a five-carbon sugar, ribose.

ATP Hydrolysis

Process where ATP is broken down, releasing energy.

Enzymes

Protein catalysts that speed up reactions by lowering the required activation energy.

Substrates

Reactant molecules that interact at the enzyme’s active site.

Active Site

Specific region on the enzyme where the substrate binds.

Induced Fit

A mild shift in the shape of the active site that optimizes reactions.

Denature

Loss of shape of an enzyme, often due to suboptimal temperatures.

Enzyme Regulators

Molecules that inhibit or promote enzyme function.

Competitive Inhibitors

Inhibitors that have a similar shape to the substrate and compete for the active site.

Noncompetitive Inhibitors

Inhibitors that bind to the enzyme at a different location, causing a slower reaction rate.

Maximal Rate

Speed of a reaction when substrate is not limited.

Allosteric Inhibitors

Inhibitors that modify the active site of the enzyme so that substrate binding is reduced or prevented.

Allosteric Activators

Activators that modify the active site of the enzyme so that the affinity for the substrate increases.

Cofactors

Inorganic ions required by some enzymes for function.

Coenzymes

Organic molecules, including ATP, NADH+, and vitamins, required by some enzymes for function.

Feedback Inhibition

Where the end product of a metabolic pathway inhibits an upstream step.

Bioenergetics

Study of energy flow through a living system.

Sun

The energy that sustains most of Earth's life forms.

Photosynthesis

Capturing energy from the sun to convert CO2 and H2O into glucose.

Cellular Respiration

Releasing energy stored in glucose, regenerating CO2 and H2O.

Chemical Energy

Stored in chemical bonds; energy released.

Energy

Exchanged in a metabolic reaction.

ΔH (Change in Total Energy)

Total energy of the system.

Entropy (ΔS)

Energy lost to disorder.

Spontaneous

Can occur without the addition of energy.

Hump in Free Energy Diagram

The reason why spontaneous reactions do not necessarily occur quickly.

Activation Energy

Energy required for a reaction to proceed.

Heat Energy

Main source for activation energy in a cell.

Activation Energy

Lower if the reaction is catalyzed.

First Law

States that the total amount of energy in the universe is constant.

Second Law

States that the transfer of energy is not completely efficient.

Heat Energy

Lost when plants utilize sunlight during photosynthesis.

ATP Structure

Adenosine backbone with three phosphate groups attached.

High-Energy Bonds

The bonds that link the phosphate groups in ATP.

Sodium-Potassium Pump

Integral protein that uses energy from ATP hydrolysis to pump ions.

Catalysts

Speed up reactions by lowering the required activation energy.

3D Shape

Determines enzyme-substrate specificity.

AAs of the Active Site

Important for the enzyme's function.

Suboptimal Temperatures

Can denature the enzyme.

Suboptimal pHs

Can reduce substrate-enzyme binding.

Regulation of Enzyme Activity

Helps cells control their environment to meet their specific needs.

Allosteric Regulators

Modify the active site of the enzyme.

Some Enzymes

Require one or more cofactors or coenzymes to function.

End Product of Pathway

Inhibits an upstream step.

ATP

An allosteric inhibitor for some enzymes involved in cellular respiration.

Anabolism

The general process of building larger molecules from smaller ones.

Catabolism

The general process of breaking down larger molecules into smaller ones.

Transition State

A state where molecules are contorted and unstable, allowing bonds to be broken or made.