AP Bio Chapter 8 - Metabolism Flashcards

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Questions and Answers

What is metabolism?

The energy available for release in a chemical reaction

The study of energy transformations

A metabolic process that consumes energy

The total of an organism's chemical reactions (correct)

What is a metabolic pathway?

A series of defined steps that alter a specific molecule, resulting in a specific product.

What does a catabolic pathway do?

Breaks down complex molecules into simpler compounds.

What is an anabolic pathway?

A metabolic process that consumes energy to build complicated molecules. Signup and view all the answers

What is bioenergetics?

The study of how energy flows through living organisms. Signup and view all the answers

Define kinetic energy.

The relative motion of an object. Signup and view all the answers

Define heat energy.

Kinetic energy associated with random movement of atoms or molecules. Signup and view all the answers

Define potential energy.

The energy that matter possesses due to its location or structure when at rest. Signup and view all the answers

What is chemical energy?

Potential energy available for release in a chemical reaction. Signup and view all the answers

What does the first law of thermodynamics state?

The energy of the universe is constant; it can be transferred or transformed but not created or destroyed. Signup and view all the answers

What does the second law of thermodynamics state?

Every energy transfer increases the entropy of the universe. Signup and view all the answers

What is free energy?

The portion of a system's energy that can perform work at uniform temperature and pressure. Signup and view all the answers

What does enzyme refer to?

A macromolecule that acts as a catalyst in biochemical reactions. Signup and view all the answers

Define activation energy.

The initial investment of energy required to start a reaction. Signup and view all the answers

What is the enzyme-substrate complex?

The entity formed when an enzyme bonds to a substrate. Signup and view all the answers

Define allosteric regulation.

When a molecule bonds to an enzyme at a location other than the active site, causing a conformational change. Signup and view all the answers

A +G coupled with an exergonic reaction and with the addition of a catalyst ____________ the reaction.

encourages Signup and view all the answers

A -G with no addition of a catalyst ________________ the reaction.

discourages Signup and view all the answers

A +G without a coupled reaction and without a catalyst ________________ the reaction.

discourages Signup and view all the answers

What is cooperativity in enzyme activity?

A mechanism amplifying the response of an enzyme to a substrate through induced fit. Signup and view all the answers

What causes feedback inhibition in metabolic pathways?

The inhibitory binding of an end product to an early enzyme in the pathway. Signup and view all the answers

Where are enzymes for cellular respiration found?

Mitochondria. Signup and view all the answers

What does the lock-and-key model of enzymes suggest?

Enzymes are highly specific with only one substrate fitting into an active site. Signup and view all the answers

What is the optimal temperature range for enzymes in the human body?

35-40 degrees Celsius. Signup and view all the answers

What is the optimal pH range for enzymes in the human body?

6-8. Signup and view all the answers

Study Notes

Metabolism Overview

Metabolism encompasses all chemical reactions in an organism, showcasing life through molecular interactions in cellular environments.
Metabolic pathways are sequences of reactions starting with a specific molecule, which is transformed through defined steps by specific enzymes, culminating in a particular product.

Catabolic and Anabolic Pathways

Catabolic pathways break down complex molecules into simpler compounds, releasing energy; cellular respiration exemplifies this by converting glucose into carbon dioxide and water.
Anabolic pathways utilize energy to construct complex molecules from simpler ones, such as synthesizing proteins from amino acids, leveraging energy sourced from catabolic processes.

Energy Concepts

Bioenergetics studies energy flow in organisms, with energy defined as the capacity to initiate change.
Kinetic energy relates to an object's motion; potential energy refers to energy due to an object's position or structure.
Chemical energy, a type of potential energy, is available for release in chemical reactions, notably high in glucose.

Thermodynamics Principles

Thermodynamics examines energy transformation; the first law asserts energy conservation—energy cannot be created or destroyed, only converted.
The second law states that energy transformations increase entropy, indicating a natural trend towards disorder.

Free Energy and Stability

Free energy indicates a system's capacity to do work; it is high in unstable systems (+G) and low in stable systems (-G).
Exergonic reactions release free energy, signified by negative Gibbs free energy, while endergonic reactions absorb energy and are characterized by positive Gibbs free energy.

Cellular Work Types

Chemical work facilitates non-spontaneous reactions, such as polymer synthesis.
Transport work involves moving substances across membranes against spontaneous movement.
Mechanical work relates to movements like muscle contraction and cilia beating.

ATP and Energy Coupling

ATP, composed of ribose, adenine, and three phosphate groups, serves as the primary energy currency in cells.
Energy coupling refers to the process where an exergonic reaction drives an endergonic one, with ATP commonly mediating this process.

Enzyme Function and Regulation

Enzymes act as catalysts, expediting reactions without being consumed; they reduce activation energy required for reactions.
The activation energy is the energy necessary to initiate biochemical reactions, and the enzyme-substrate complex is formed when an enzyme binds to its substrate at the active site.
Enzymes can be influenced by inhibitors, which can be competitive (competing with substrates) or noncompetitive (binding elsewhere to alter enzyme shape).

Enzyme Models and Reactions

The lock-and-key model describes enzyme specificity, while the induced fit model illustrates how enzymes and substrates shape each other for optimal interaction.
Feedback inhibition regulates metabolic pathways, where end products inhibit early enzymes to conserve resources.

Environmental Effects on Enzymes

Optimal conditions for enzyme activity include a temperature range of 35-40°C and a pH range of 6-8, crucial for maintaining enzymatic function in the human body.

Summary of Key Reactions and Energies

Hydrolysis of ATP (ATP → ADP + P(i)) releases -7.3 kcal/mol of energy, while synthesis (ADP + P(i) → ATP + H2O) requires +7.3 kcal/mol.
Aerobic cellular respiration (C6H12O6 + 6O2 → 6CO2 + 6H2O) releases -686 kcal/mol of Gibbs free energy.

Additional Terms

Entropy reflects disorder in a system; enthalpy indicates order.
Saturation in enzymes occurs when products are promptly replaced by new substrates.
Cofactors assist enzymes in reactions; coenzymes, typically vitamins, are inorganic cofactors.

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Description

Explore key concepts of metabolism in this set of flashcards for AP Biology Chapter 8. Learn important terms and definitions related to metabolic pathways and the chemical reactions that sustain life. Perfect for quick review and memorization.