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Chapter 1Chapter 1
The Molecular Logic of LifeThe Molecular Logic of Life Biochemistry explains diverse formsBiochemistry explains diverse forms
of life in unifying chemical terms.of life in unifying chemical terms.
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figure 1-1Some characteristics of
living matter.
Chemical complexity;
Use energy;
Biological reproduction
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gure -
Diverse living
organisms sharecommon chemical
features.Same basic
structural units(cells)
Same kinds ofmacromolecules
(DNA, RNA,proteins)
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figurel-3Monomeric
subunits in linearsequences can
spell infinitelycomplex message
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All macromolecules are constructedAll macromolecules are constructed
from a few simple compoundsfrom a few simple compounds All living organism build moleculesAll living organism build molecules
from the same kinds offrom the same kinds of monomericmonomericsubunits.subunits.
The structure of a macromoleculesThe structure of a macromoleculesdetermines specific biological function.determines specific biological function.
Each genus and species is defined byEach genus and species is defined byits distinctive set of macromolecules.its distinctive set of macromolecules.
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Energy production andEnergy production and
consumption in metabolismconsumption in metabolism
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figure 1-4
Living organisms are
not at equilibriumwith their
surroundings.
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he dynamic steady state. A dynamic steady state
sults when the rate of appearance of a cellular
omponent is exactly matched by the rate of its
figure l-5
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Organisms transform energy andOrganisms transform energy and
matter from their surroundingmatter from their surrounding BioenergeticsBioenergetics
Universe: system and surroundingsUniverse: system and surroundings System: closed, isolated, openSystem: closed, isolated, open
A living organism is an open system.A living organism is an open system.
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Living organisms create and maintainLiving organisms create and maintain
their complex, orderly structurestheir complex, orderly structuresusing energy extracted from fuels orusing energy extracted from fuels or
sunlight.sunlight.
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figure l-6
During metabolic
transductions, the
randomness of the system
plus surroundings(expressed quantitatively
as entropy) increases as
the potential energy ofcomplex nutrient
molecules decreases.
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The first law of thermodynamicsThe first law of thermodynamics
In any physical or chemical change, theIn any physical or chemical change, the
total amount of energy in the universetotal amount of energy in the universeremains constant, although the form of theremains constant, although the form of the
energy may change.energy may change.
Th fl f l id
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The flow of electrons providesThe flow of electrons provides
energy for organismsenergy for organisms
-
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Sunlight is the ultimate source of
all biological energy.Thermonuclear reactions in the su
produce helium from hydrogen an
release electromagnetic energy,
which is transmitted to the earth a
light and converted into chemicalenergy by plants and some algae
and bacteria.
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figure l-8
hotosynthetic organisms are the ultimate providers of
- - -
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Energy coupling
in mechanical
and chemical
processes.
figure 1-9
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Free energy (G):Free energy (G): the amount of energythe amount of energy
available to do workavailable to do work Free Energy Change (G): is the
portion of the total energy change whichis available to do work as a reaction
proceeds to equilibrium at constanttemperature and pressure.
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The sign of the free energy change in a process
tells us whether that process or its reverse isthermodynamically favorable.
G
0 exergonic reaction G0 endergonic reaction
G of a spontaneously reacting system is
always negative
At equilibriumG0
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denosine triphosphate (ATP). The removal ofe terminal phosphoryl of ATP (shaded pink) is
ighly exergonic, and this reaction is coupled toany endergonic reactions in the cell as in the
figure l-10
nzymes promote sequences of chemical reactions
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ner y chan es durin a chemical reaction.
gure 1-11
nzymes promote sequences of chemical reactions
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n enzyme increases the rate of a specific chemicalaction.
figure l-12
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A linear metabolic pathway.
figure 1-13
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ATP is the shared
chemical intermediatelinking energy- releasing
to energy-requiring cell
processes.
figure l-14
Metabolism is regulated to achieve balance and
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eedback inhibition. Regulation byeedback inhibition in a typical
ynthetic (anabolic) pathway.
figure l-15
Metabolism is regulated to achieve balance and
economy
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Biological Information TransferBiological Information Transfer
Genetic continuity is vested in DNAGenetic continuity is vested in DNA
molecules.molecules. The structure of DNA allows for its repairThe structure of DNA allows for its repair
and replication with nearand replication with near--perfect fidelity.perfect fidelity. Changes in the hereditary instructionsChanges in the hereditary instructions
allow evolution.allow evolution.
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The complementary
structure of DNA.Complementarity between
the two strands accounts
for the accurate replicationessential for genetic
continuity.
figure 1-17
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gure 1-18
ole of mutation in evolution. The gradual accumulation
f mutations overlong periods of time results in new
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figure l-19
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figure l 19
The linear
sequence in DNA
encodes proteins
with three-
dimensional
structures.
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NoncovalentNoncovalent interactionsinteractions
stabilize threestabilize three--dimensionaldimensionalstructuresstructures