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Section 1
Introduction to Biochemical
Principles
Chapter 1
Biochemistry: An Introduction
Life: It is a Mystery!
Life: It is a Mystery!
Figure 1.1 Diversity of Life
Why study biochemistry?
Foundation upon which
all of the modern life
sciences are built
Biology can’t be done
without biochemistry
Life and its Diversity
Life is Resilient
Section 1.1: What Is Life?
All Life Obeys the Same
Chemical and Physical Laws:
Life is complex and dynamic
Life is organized and selfsustaining
Life is cellular
Life is information-based
Life adapts and evolves
Figure 1.3 Hierarchical Organization
Section 1.2: Biomolecules
Living organisms composed of inorganic and organic
molecules
Water is the matrix of life
Six principal elements: carbon, hydrogen, oxygen,
nitrogen, phosphorous, and sulfur
Trace elements are also important (i.e., Na+, K+, Mg2+,
and Ca2+)
Section 1.2: Biomolecules
Section 1.2: Biomolecules
Major Classes of Small Biomolecules
Many organic molecules are relatively small (less than
1000 Daltons (Da))
Families of small molecules: amino acids, sugars, fatty
acids, and nucleotides
Section 1.3: Is the Living Cell a Chemical Factory?
The properties of even the simplest cells are
remarkable
Autopoiesis has been coined to describe the
remarkable properties of living organisms
Metabolism is defined as:
The acquisition and utilization of energy
Synthesis of molecules needed for cell structure and
function
Growth and development
Removal of waste products
Section 1.3: Is the Living Cell a Chemical Factory?
Biochemical Reactions
Nucleophilic substitution
Elimination
Addition
Isomerization
Oxidation-Reduction
Section 1.3: Is the Living Cell a Chemical Factory?
Energy
Energy is defined as the capacity to do work
Cells generate most of their energy with redox
reactions
The energy captured when electrons are transferred
from an oxidizable molecule to an electron-deficient
molecule is used to drive ATP synthesis
Acquiring energy from the environment happens in
distinct ways:
Autotrophs
Heterotrophs
Section 1.3: Is the Living Cell a Chemical Factory?
Overview of Metabolism
Metabolic pathways come in two types:
anabolic and catabolic
Anabolic: large complex molecules
synthesized from smaller precursors
Catabolic: large complex molecules
degraded into smaller, simpler products
Energy transfer pathways capture energy
and transform it into a usable form
Signal transduction pathways allow cells
to receive and respond to signals
Figure 1.21 A Biochemical
Pathway
Section 1.3: Is the Living Cell a Chemical Factory?
Figure 1.22 Anabolism and Catabolism
Section 1.3: Is the Living Cell a Chemical Factory?
Biological Order
The coherent unity that is observed in all
organisms:
Synthesis of biomolecules
Transport across membranes
Cell movement
Waste removal
Section 1.4: Systems Biology
Systems Biology: Living
Organisms Regarded as
Integrated Systems
Emergence: Interaction of
parts can lead to new
properties
Figure 1.23 Feedback Mechanisms
Section 1.4: Systems Biology
Robustness: Many biological
systems remain stable despite
perturbations
Modularity: Complex systems
are composed of modules
Figure 1.23 Feedback Mechanisms
Chapter 2
Living Cells
Section 2.1: Basic Themes
Figure 2.2 Hydrophobic Interactions Between Water and a Nonpolar Substance
Understanding of the biological context of
biochemical processes is enhanced by examining
six key concepts:
Section 2.1: Basic Themes
Figure 2.2 Hydrophobic Interactions Between Water and a Nonpolar Substance
Water
Unique polar structure
Among its most important properties is interaction
with a wide range of substances
Section 2.1: Basic Themes
Biological Membranes
Thin, flexible, and stable sheet-like structures
Selective physical barrier
Phospholipid bilayer with integral and peripheral
membrane proteins
Figure 2.3 Membrane Structure
Section 2.1: Basic Themes
Self-Assembly
Many biomolecules spontaneously undergo selfassembly into supermolecular structures
Molecular Machines
Many multisubunit complexes involved in cellular
processes function as molecular machines
Figure 2.5
Biological Machines
Section 2.1: Basic Themes
Figure 2.6
Volume Exclusion
Macromolecular Crowding
The interior space within cells is dense and crowded
The excluded volume may be between 20% and 40%
Signal Transduction
Reception, transduction, and response
Section 2.2: Structure of Prokaryotic Cells
Figure 2.7 Typical
Bacterial Cell
Prokaryotes include bacteria and archaea
They have common features: cell wall, plasma membranes,
circular DNA, and no membrane-bound organelles
Section 2.2: Structure of Prokaryotic Cells
Figure 2.8
Bacterial Cell
Section 2.2: Structure of Prokaryotic Cells
Cell Wall
The prokaryotic cell
wall is a complex semirigid structure
primarily for support
and protection
The cell wall is
primarily composed of
peptidoglycan
Figure 2.8 Bacterial Cell
Section 2.2: Structure of Prokaryotic Cells
Figure 2.9 Bacterial
Plasma Membrane
Plasma Membrane
Directly inside the cell wall is the plasma membrane,
a phospholipid bilayer
A selectively permeable membrane that may be
involved in photosynthesis or respiration
Section 2.2: Structure of Prokaryotic Cells
Cytoplasm
Prokaryotic cells do have
functional compartments
Nucleoid, which is centrally
located and contains the circular
chromosome
Also contains small DNA
plasmids
Inclusion bodies are large
granules that contain organic or
inorganic compounds
Figure 2.10 Bacterial Cytoplasm
Section 2.2: Structure of Prokaryotic Cells
Figure 2.7 Typical
Bacterial Cell
Pili and Flagella
Many bacteria have external appendages
Pili (pilus) are for attachment and sex
Flagella (flagellum) are used for locomotion
Section 2.3: Structure of Eukaryotic Cells
Eukaryotic cells are structurally complex
Membrane-bound organelles and the endomembrane
system increase surface area for chemical reactions
Figure 2.11 Animal Cell
Section 2.3: Structure of Eukaryotic Cells
Important structures: plasma membrane,
endoplasmic reticulum, Golgi apparatus, nucleus,
lysosomes, mitochondria, chloroplasts, ribosomes,
and the cytoskeleton
Figure 2.12 Plant Cell
Section 2.3: Structure of Eukaryotic Cells
Figure 2.13
Plasma Membrane
Plasma Membrane
Isolates the cell and is selectively permeable
Outside the plasma membrane are the glycocalyx and
the extracellular matrix
Section 2.3: Structure of Eukaryotic Cells
Endoplasmic Reticulum
The endoplasmic
reticulum (ER) is a series
of membranous tubules,
vesicles, and flattened
sacks
The internal space is
the ER lumen
Figure 2.15
Endoplasmic Reticulum
Section 2.3: Structure of Eukaryotic Cells
Two types:
Rough ER functions
include protein synthesis,
folding, and glycosylation
Smooth ER functions
include lipid biosynthesis
and Ca2+ storage
Figure 2.15
Endoplasmic Reticulum
Section 2.3: Structure of Eukaryotic Cells
Golgi Apparatus
The Golgi apparatus is
formed of large, flattened,
sac-like membranous
vesicles
Processes, packages, and
distributes cell products
Has a cis and a trans
face (cisternae)
Figure 2.16 The Golgi Apparatus
Section 2.3: Structure of Eukaryotic Cells
Cisternal maturation model
vesicles are recycled back to
the cis Golgi from the trans
Golgi
Secretory products
concentrated at the trans
Golgi into secretory vesicles
Involved in exocytosis
Figure 2.17 Exocytosis
Section 2.3: Structure of Eukaryotic Cells
Nucleus
The nucleus is the most
prominent organelle
Contains the hereditary
information
Site of transcription
Nuclear components:
Nucleoplasm
Chromatin (genome)
Nuclear matrix
Nucleolus
Nuclear envelope
Figure 2.18 Eukaryotic Nucleus
Section 2.3: Structure of Eukaryotic Cells
The nuclear envelope
surrounds the nucleoplasm
The nuclear envelope has
nuclear pores referred to as
nuclear pore complexes
Structures through which
pass most of the molecules
that enter and leave the
nucleus
Figure 2.19 The Nuclear
Pore Complex
Section 2.3: Structure of Eukaryotic Cells
Vesicular Organelles
The eukaryotic cell has
vesicles
Vesicles originate in the ER,
Golgi and/or via endocytosis
Figure 2.20 Receptor-Mediated Endocytosis
Section 2.3: Structure of Eukaryotic Cells
Phagocytosis
Receptor-mediated
endocytosis
Endocytic cycle is used for
recycling and remodeling of
membranes
Figure 2.20 Receptor-Mediated Endocytosis
Section 2.3: Structure of Eukaryotic Cells
Vesicular Organelles Continued
Lysosomes are vesicles that
contain digestive enzymes
Enzymes are acid hydrolases
Degrade debris in cells and
involved in autophagy
Figure 2.21 Lysosomes
Section 2.3: Structure of Eukaryotic Cells
Mitochondria
Figure 2.23 The Mitochondrion
The mitochondria
(mitochondrion) are
recognized as the site of
aerobic metabolism
Mitochondria are the
principle source of cellular
energy
Have inner and outer
membrane surrounding the
matrix
Have DNA and ribosomes
Section 2.3: Structure of Eukaryotic Cells
Peroxisomes
The peroxisome is a small organelle containing
oxidative enzymes
Detoxifies peroxides (e.g., H2O2)
Section 2.3: Structure of Eukaryotic Cells
Plastids
Figure 2.25 Chloroplast
Plastids are organelles found
only in plants, algae, and some
protists
Two types: leucoplasts and
chromoplasts
Chloroplasts are
chromoplasts specialized for
photosynthesis
Section 2.3: Structure of Eukaryotic Cells
Cytoskeleton
The cytoskeleton is an intricate supportive network
of fibers, filaments, and associated proteins
Three main components:
Microtubules
Microfilaments
Intermediate filaments
Main functions includE cell shape and structure,
large- and small-scale cell movement, solid-state
biochemistry, and signal transduction
Section 2.3: Structure of Eukaryotic Cells
Figure 2.26 The Cytoskeleton
Section 2.3: Structure of Eukaryotic Cells
Cytoskeleton
Cilia and flagella, whip-like appendages encased in
plasma membrane, are highly specialized for their
roles in propulsion
Bending occurs via ATP-driven structural
changes in dynein molecules
Section 2.3: Structure of Eukaryotic Cells
Figure 2.27 Cilia and
Flagella
Chapter 3
Water: The Matrix of Life
Section 3.1: Molecular Structure of Water
Water is essential for life
Water’s important properties include:
Chemical stability
Remarkable solvent properties
Role as a biochemical reactant
Hydration
Section 3.1: Molecular Structure of Water
Water has a tetrahedral
geometry
Oxygen is more electronegative
than hydrogen
Figure 3.2 Tetrahedral
Structure of Water
Section 3.1: Molecular Structure of Water
Larger oxygen atom has partial negative charge
(d-) and hydrogen atoms have partial positive
charges (d+)
Figure 3.3 Charges on a Water Molecule
Figure 3.4 Water Molecule
Section 3.1: Molecular Structure of Water
Bond between oxygen and hydrogen is polar
Water is a dipole because the positive and
negative charges are separate
Figure 3.5 Molecular
Dipoles in an Electric
Field
Section 3.1: Molecular Structure of Water
An electron-deficient hydrogen
of one water is attracted to the
unshared electrons of water
forming a hydrogen bond
Can occur with oxygen,
nitrogen, and fluorine
Has electrostatic (i.e., opposite
charges) and covalent (i.e.,
electron sharing) characteristics
Figure 3.6 Hydrogen Bond
Section 3.2: Noncovalent Bonding
Noncovalent interactions are electrostatic
Weak individually, but play vital role in biomolecules
because of cumulative effects
Section 3.2: Noncovalent Bonding
Three most important noncoavalent bonds:
Ionic interactions
Van der Waals forces
Hydrogen bonds
Section 3.2: Noncovalent Bonding
Ionic Interactions
Oppositely charged ions attract one another
Ionized amino acid side chains can form salt bridges
with one another
Biochemistry primarily investigates the interaction
of charged groups on molecules, which differs from
ionic interactions like those of ionic compounds (e.g.,
NaCl)
Section 3.2: Noncovalent Bonding
Hydrogen Bonds
Electron-deficient hydrogen is
weakly attracted to unshared
electrons of another oxygen or
nitrogen
Large numbers of hydrogen
bonds lead to extended network
Figure 3.7 Tetrahedral
Aggregate of Water
Molecules
Section 3.2: Noncovalent Bonding
Van der Waals Forces
Occur between neutral,
permanent, and/or induced
dipoles
Three types:
Dipole-dipole interactions
Dipole-induced dipole
interactions
Induced dipole-induced
dipole interactions
Figure 3.8 Dipolar Interactions
Section 3.3: Thermal Properties of Water
Water’s melting and boiling points are
exceptionally high due to hydrogen bonding
Each water molecule can form four hydrogen bonds
with other water molecules
Extended network of hydrogen bonds
Section 3.3: Thermal Properties of Water
Figure 3.9 Hydrogen Bonding
Between Water Molecules in Ice
Maximum number of hydrogen bonds form when
water has frozen into ice
Open, less-dense structure
Section 3.3: Thermal Properties of Water
Water has an exceptionally high heat of fusion and
heat of vaporization
Helps to maintain an organism’s internal
temperature
Section 3.4: Solvent Properties of Water
Figure 3.10 Solvation
Spheres
Water is the ideal biological solvent
Hydrophilic Molecules, Cell Water Structuring, and
Sol-Gel Transitions
Water can dissolve ionic and polar substances
Shells of water molecules form around ions forming
solvation spheres
Section 3.4: Solvent Properties of Water
Figure 3.11 Diagrammatic
View of Structured Water
Structured Water
Water is rarely free
flowing
Water is associated
with macromolecules
and other cellular
components
Forms complex threedimensional bridges
between cellular
components
Section 3.4: Solvent Properties of Water
Figure 3.12 Amoeboid
Movement
Sol-Gel Transitions
Cytoplasm has properties of a gel (colloidal
mixture)
Transition from gel to sol important in cell
movement
Amoeboid motion provides an example of
regulated, cellular, sol-gel transitions
Section 3.4: Solvent Properties of Water
Figure 3.13 The
Hydrophobic Effect
Hydrophobic Molecules and the Hydrophobic Effect
Small amounts of nonpolar substances are excluded
from the solvation network forming droplets
This hydrophobic effect results from the solvent
properties of the water and is stabilized by van der
Waals interactions
Section 3.4: Solvent Properties of Water
Amphipathic Molecules
Contain both polar and
nonpolar groups
Amphipathic molecules
form micelles when mixed
with water
Important feature for
the formation of
cellular compartments
Figure 3.14 Formation of Micelles
Section 3.4: Solvent Properties of Water
Figure 3.15 Osmotic
Pressure
Osmotic Pressure
Osmosis is the spontaneous passage of solvent
molecules through a semipermeable membrane
Osmotic pressure is the pressure required to stop
the net flow of water across the membrane
Osmotic pressure depends on solute concentration
Section 3.4: Solvent Properties of Water
Can be measured with an osmometer
or calculated ( =iMRT)
Cells may gain or lose water because
of the environmental solute
concentration
Solute concentration differences
between the cell and the environment
can have important consequences
Isotonic solution
Hypotonic solution
Hypertonic solution
Figure 3.17 Effect of Solute Concentration on Animal Cells
Section 3.4: Solvent Properties of Water
Proteins with ionizable amino acid side chains affect
cellular osmolarity by attracting ions of opposite
charge
There is asymmetry of charge across the membrane
due to ions forming an electrical gradient (membrane
potential)
Unlike animal cells, plant cells use osmotic pressure
to drive growth via turgor pressure
Section 3.5: Ionization of Water
Water can occasionally ionize, forming a hydrogen
ion (H+) and a hydroxide ion (OH-)
In an aqueous solution, a proton combines with a
water molecule to form H3O+ (hydronium ion)
H2O  H+ + OH- (reversible)
Section 3.5: Ionization of Water
The ion product of water is referred to as Keq[H2O]
or Kw = [H+][OH-]
Kw at 25°C and 1 atm pressure is 1.0  10-14
Kw is temperature-dependent; therefore, pH is
temperature-dependent as well
Section 3.5: Ionization of Water
Acids, Bases, and pH
An acid is a proton donor
A base is a proton acceptor
Most organic molecules that donate or accept
protons are weak acids or weak bases
A deprotonated product of a dissociation reaction
is a conjugate base
Section 3.5: Ionization of Water
The pH scale can be used to
measure hydrogen ion
concentration
pH=-log[H+]
Figure 3.18 The pH Scale and the pH Values of
Common Fluids
Section 3.5: Ionization of Water
pKa is used to express the
strength of a weak acid
Lower pKa equals a stronger
acid
pKa=-logKa
Ka is the acid dissociation
constant
Figure 3.18 The pH Scale and the pH Values of
Common Fluids
Section 3.5: Ionization of Water
Section 3.5: Ionization of Water
Buffers
Regulation of pH is universal and essential for all
living things
Certain diseases can cause changes in pH that can
be disastrous
Acidosis and Alkalosis
Buffers help maintain a relatively constant
hydrogen ion concentration
Commonly composed of a weak acid and its
conjugate base
Section 3.5: Ionization of Water
Buffers Continued
Establishes an
equilibrium between
buffer’s components
Follows Le Chatelier’s
principle
Equilibrium shifts in
the direction that
relieves the stress
Figure 3.19 Titration of Acetic Acid
with NaOH
Section 3.5: Ionization of Water
Henderson-Hasselbalch Equation
Establishes the relationship between pH and pKa for
selecting a buffer
Buffers are most effective when they are composed of
equal parts weak acid and conjugate base
Best buffering occurs 1 pH unit above and below the
pKa
Henderson-Hasselbalch Equation
pH = pKa + log
[A-]
[HA]
Section 3.5: Ionization of Water
Worked Problem 3.5 (Page 91)
Calculate the pH of a mixture of 0.25 M acetic acid
(CH3COOH) and 0.1 M sodium acetate (NaC2H3O2)
The pKa of acetic acid is 4.76
Solution:
pH = pKa + log
pH = 4.76 + log
[acetate]
[acetic acid]
[0.1]
[0.25]
= 4.76 + 0.398 = 4.36
Section 3.5: Ionization of Water
Figure 3.20 Titration of
Phosphoric Acid with
NaOH
Weak Acids with Multiple Ionizable Groups
Each ionizable group can have its own pKa
Protons are released in a stepwise fashion
Section 3.5: Ionization of Water
Physiological Buffers
Buffers adapted to solve specific physiological
problems within the body
Bicarbonate Buffer
One of the most important buffers in the blood
CO2 + H2O  H+ + HCO3- (HCO3- is bicarbonate):
This is a reversible reaction
Carbonic anhydrase is the enzyme responsible
Section 3.5: Ionization of Water
Phosphate Buffer
Consists of H2PO4-/HPO42(weak acid/conjugate base)
H2PO4-  H+ + HPO42Important buffer for
intracellular fluids
Protein Buffer
Proteins are a significant
source of buffering capacity
(e.g., hemoglobin)
Figure 3.21 Titration of
H2PO4- by Strong Base
Chapter 4
Energy
Section 4.1: Thermodynamics
Energy is the basic constituent of the universe
Energy is the capacity to do work
In living organisms, work is powered with the
energy provided by ATP
Thermodynamics is the study of energy
transformations that accompany physical and
chemical changes in matter
Bioenergetics is the branch that deals with
living organisms
Section 4.1: Thermodynamics
Bioenergetics is especially important in
understanding biochemical reactions
These reactions are affected by three factors:
Enthalpy—total heat content
Entropy—state of disorder
Free Energy—energy available to do chemical work
Section 4.1: Thermodynamics
Three laws of thermodynamics:
First Law of Thermodynamics—Energy cannot be
created nor destroyed, but can be transformed
Second Law of Thermodynamics—Disorder always
increases
Third Law of Thermodynamics—As the temperature of a
perfect crystalline solid approaches absolute zero,
disorder approaches zero
Section 4.1: Thermodynamics
First two laws are powerful
biochemical tools
Thermodynamic transformations
take place in a universe composed
of a system and its surroundings
Energy exchange between a
system and its surroundings can
happen in two ways: heat (q) or
work (w)
Figure 4.2 A Thermodynamic
Universe
Work is the displacement or
movement of an object by force
Section 4.1: Thermodynamics
First Law of Thermodynamics
Expresses the relationship between internal energy
(E) in a closed system and heat (q) and work (w)
Total energy of a closed system (e.g., our universe)
is constant
DE = q + w
Unlike a human body, which is an open system
Enthalpy (H) is related to internal energy by the
equation: H = E + PV
DH is often equal to DE (DH = DE)
Section 4.1: Thermodynamics
First Law of Thermodynamics Continued
If DH is negative (DH <0) the reaction gives off heat:
exothermic
If is DH positive (DH >0) the reaction takes in heat
from its surroundings: endothermic
In isothermic reactions (DH =0) no heat is
exchanged
Reaction enthalpy can also be calculated:
DHreaction = SDHproducts  SDHreactants
Standard enthalpy of formation per mole (25°C,
1 atm) is symbolized by DHf°
Section 4.1: Thermodynamics
Figure 4.3 A Living Cell as a
Thermodynamic System
Second Law of Thermodynamics
Physical or chemical changes resulting in a release
of energy are spontaneous
Nonspontaneous reactions require constant energy
input
Section 4.1: Thermodynamics
As a result of spontaneous
processes, matter and
energy become more
disorganized
Gasoline combustion
The degree of disorder is
measured by the state
function entropy (S)
Figure 4.4 Gasoline Combustion
Section 4.1: Thermodynamics
Second Law of Thermodynamics Continued
Entropy change for the universe is positive for every
spontaneous process
DSuniv = DSsys + DSsurr
Living systems do not increase internal disorder; they
increase the entropy of their surroundings
For example, food consumed by animals to provide
energy and structural materials needed are converted
to disordered waste products (i.e., CO2, H2O and heat)
Organisms with a DSuniv = 0 or equilibrium are dead
Section 4.2: Free Energy
Free energy is the most
definitive way to predict
spontaneity
Gibbs free energy change or DG
Figure 4.5 The Gibbs
Free Energy Equation
Negative DG indicates
spontaneous and exergonic
Positive DG indicates
nonspontaneous and endergonic
When DG is zero, it indicates a
process at equilibrium
Section 4.2: Free Energy
Standard Free Energy Changes
Standard free energy, DG°, is defined for reactions
at 25°C,1 atm, and 1.0 M concentration of solutes
Standard free energy change is related to the
reactions equilibrium constant, Keq
DG° = -RT ln Keq
Allows calculation of DG° if Keq is known
Because most biochemical reactions take place at or
near pH 7.0 ([H+] = 1.0  10-7 M), this exception can be
made in the 1.0 M solute rule in bioenergetics
The free energy change is expressed as DG°′
Section 4.2: Free Energy
Figure 4.6 A Coupled Reaction
Coupled Reactions
Many reactions have a positive DG°′
Free energy values are additive in a reaction
sequence
If a net DG°′ is sufficiently negative, forming the
product(s) is an exergonic process
Section 4.2: Free Energy
The Hydrophobic Effect Revisited
Understanding the spontaneous aggregation of
nonpolar substances is enhanced by understanding
thermodynamic principles
The aggregation decreases the surface area of their
contact with water, increasing its entropy
The free energy of the process is negative; therefore,
it proceeds spontaneously
Spontaneous exclusion of water is important in
membrane formation and protein folding
Section 4.3: The Role of ATP
Figure 4.7 Hydrolysis
of ATP
Adenosine triphosphate is a nucleotide that plays
an extraordinarily important role in living cells
Hydrolysis of ATP  ADP + Pi provides free energy
Section 4.3: The Role of ATP
Drives reactions of
several types:
1. Biosynthesis of
biomolecules
2. Active transport
across membranes
3. Mechanical work
such as muscle
contraction
Figure 4.8 The Role of ATP
Section 4.3: The Role of ATP
Structure of ATP is ideally
suited for its role as
universal energy currency
Its two terminal
phosphoryl groups are
linked by
phosphoanhydride bonds
Specific enzymes
facilitate ATP hydrolysis
Figure 4.9 Structure of ATP
Section 4.3: The Role of ATP
Figure 4.10 Transfer of
Phosphoryl Groups
The tendency of ATP to undergo hydrolysis is an
example of its phosphoryl group transfer potential
ATP acts as energy currency, because it can carry
phosphoryl groups from high-energy compounds to
low-energy compounds
Section 4.3: The Role of ATP
Section 4.3: The Role of ATP
Figure 4.11 Contributing Structure of the Resonance Hybrid of Phosphate
Several factors need to be considered to understand
why ATP is so exergonic:
1. At physiological pH, ATP has multiple negative charges
2. Because of resonance stabilization, the products of ATP
hydrolysis are more stable than resonance-restricted ATP
Resonance is when a molecule has two or more
alternative structures that differ only in the position of
their electrons
3. Hydrolysis products of ATP are more easily solvated
4. Increase in disorder with more molecules