Biology Chapter 7 Flashcards

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Questions and Answers

What is G (free energy)?

Energy available to do work.

__________________________ explain why organisms cannot produce energy but must continuously capture it from somewhere else.

The laws of thermodynamics

In every energy transaction, some energy is dissipated as ___________.

heat

In the metabolism of living things, some _____________ occur spontaneously, releasing free energy that is then available to perform work.

chemical reactions Signup and view all the answers

What is the energy currency of the cell?

ATP Signup and view all the answers

Energy transfers often occur in cells through _______________ utilizing electron carrier molecules.

redox reactions Signup and view all the answers

Chemical reactions in organisms are regulated by _____________, substances that lower the amount of energy needed to activate reactions.

enzymes Signup and view all the answers

Match the following: drugs with their effect on enzymes.

Drugs = Inhibit enzymes critical to the normal functioning of certain pathogenic organisms Signup and view all the answers

What are the main functions of enzymes?

Lower the required activation energy, speed up biological chemical reactions. Signup and view all the answers

Name factors that may affect enzyme activity.

Cofactors, temperature, genes, phosphorylation, pH Signup and view all the answers

What does the reaction ATP + H2O ⟶ ADP + P signify?

Hydrolyzes ATP Signup and view all the answers

Compliance with the second law of thermodynamics presumes that:

Entropy is increasing, maintaining order in a system requires input of energy, during any energy transformation, some energy is converted into an unusable form. Signup and view all the answers

What is kinetic energy?

Energy of motion, doing work. Signup and view all the answers

What is chemical energy in molecules?

Potential energy stored in chemical bonds. Signup and view all the answers

Define metabolism.

The sum of all chemical activities in an organism. Signup and view all the answers

What characterizes an exergonic reaction?

Releases energy Signup and view all the answers

According to the first law of thermodynamics:

Energy cannot be created or destroyed. Signup and view all the answers

What does the second law of thermodynamics state?

Supports the observation that energy available for doing work is decreasing. Signup and view all the answers

________________________ reactions may use NAD as a hydrogen/electron acceptor.

Redox Signup and view all the answers

What is the energy barrier necessary to start a chemical reaction?

The energy of activation. Signup and view all the answers

What is potential energy?

Stored energy. Signup and view all the answers

Explain what is meant by G (free energy) and relate it to changes in entropy.

Gibbs free energy is the energy associated with a chemical reaction that can do useful work. Signup and view all the answers

Enzymes are inhibited:

When an inhibitor competes for the active site on the enzyme, by specific drugs, when they bind weakly with an inhibitor, either competitively or noncompetitively, allosterically. Signup and view all the answers

Plants convert radiant energy to _________ energy.

chemical Signup and view all the answers

________________is the capacity to do work.

Energy Signup and view all the answers

_____________________ is 'stored energy'.

Potential energy Signup and view all the answers

Is the energy of motion.

Kinetic energy Signup and view all the answers

Thermodynamics is the study of _______________.

Energy transformations Signup and view all the answers

The total energy in the universe does not change. The first law of thermodynamics states that energy can be neither ________ nor _ , however, it can be __________.

created, destroyed, transformed. Signup and view all the answers

Study Notes

Energy Concepts

Free Energy (G): Energy available to perform work.
First Law of Thermodynamics: Energy cannot be created or destroyed, only transformed.
Second Law of Thermodynamics: Energy transformations increase entropy; some energy is lost as heat, leading to more disorder.

Chemical Reactions

Some chemical reactions occur spontaneously, releasing free energy for work.
Exergonic Reactions: Release energy, result in negative delta G, considered 'downhill' reactions.
Redox Reactions: Coupled oxidation and reduction processes that transfer energy stored in electrons; utilize electron carriers like NAD.

Enzyme Functionality

Enzymes: Biological catalysts that speed up reactions by lowering activation energy; coded for by genes.
Enzyme activity can be influenced by cofactors, temperature, pH, and phosphorylation.
Enzymes can be inhibited either competitively (by competing for active sites) or non-competitively.

Energy Types

Kinetic Energy: Energy of motion, enabling work.
Potential Energy: Stored energy, often found in chemical bonds.
Chemical Energy: A specific type of potential energy released during chemical reactions.

Metabolism

Metabolism: The totality of chemical activities in an organism.
ATP (adenosine triphosphate): Cell's energy currency; undergoes hydrolysis to form ADP and inorganic phosphate, releasing energy.

Thermodynamics in Biology

Thermodynamics: The study of energy transformations within biological systems.
Activation Energy: The energy barrier that must be overcome for a reaction to occur.

Plant Energy Conversion

Plants convert radiant energy from the sun into chemical energy through photosynthesis.

Miscellaneous

Entropy: A measure of disorder or randomness, which tends to increase in natural processes.
Energy Measurement: Gibbs free energy (ΔG) helps predict the spontaneity of reactions; a positive ΔG indicates a non-spontaneous reaction.

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Test your knowledge of free energy and thermodynamics with these flashcards from Biology Chapter 7. Each card presents a term along with its definition, helping you reinforce your understanding of key concepts related to energy in living organisms.