Mary K. Campbell
Shawn O. Farrell
http://academic.cengage.com/chemistry/campbell
Chapter One
Biochemistry and the Organization of Cells
Paul D. Adams • University of Arkansas
Some Basic Themes
• All living things make use of the same types of ___________,
and all use _____________
• as a result, all living things can be studied using the
methods of ____________________________
• The fundamental similarity of cells of all types makes it
interesting to speculate on the origins of life
• both cells and the biomolecules of which they are made
must have arisen ultimately from very simple molecules,
such as ______________________________________
• Field of Biochemistry draws many disciplines
• allows us to answer questions related to _____________
Biomolecules
• Organic chemistry: the study of the compounds of
____________________
• the cellular apparatus of living organisms is made up
of ____________________ compounds
• ___________________ are part of the subject matter
of organic chemistry
• the reactions of ___________________ can be
described by the methods of organic chemistry
• The experiment of Friedrich Wöhler in 1828
Levels of Structural Organization in the
Human Body
Biomolecules (Cont’d)
• _________________________: an atom or group of atoms
that shows characteristic physical and chemical properties
ATP and The Reactions for its Formation
Origins of Life
• The “_________________” theory
• all matter was originally confined in a very small space
• as the result of an explosion, it started to expand with great
force; temperature approx. 15x109 K
• the average temperature of the universe has been decreasing
ever since
• in the earliest stages of the universe, the only elements present
were H, He, and Li
• other elements were formed by
• thermonuclear reactions in stars
• explosions of stars
• the action of cosmic rays outside the stars
Relative Abundance of Important Elements
Biomolecules (Cont’d)
• Gases present in the atmosphere of the early earth included
NH3, H2S, CO, CO2, CH4, N2, H2, and H2O but not _______
• Experiments have demonstrated that important biomolecules,
such as proteins and nucleic acids, could have arisen under
____________ (nonliving) conditions from reactions of these
simple compounds
• in the earth’s oceans
• on the surface of clay particles
Biomolecules (Cont’d)
• Living cells include very large molecules, such as
•
•
•
•
________________________ ______________________
________________________ ______________________
These are polymers (Greek: poly+meros, many+parts)
Derived from monomers (Greek: mono+meros, single+part)
--amino acids --> proteins
--nucleotides --> nucleic acids
--monosaccharides --> polysaccharides
--glycerol and 3 fatty acids --> lipids
Oops! Identify the mistake above!
Informational Macromolecules
Biomolecules (Cont’d)
• _______________: a class of proteins that are biocatalysts
• the catalytic effectiveness of a given enzyme depends on its
_______________________________________
• Genetic code: the relationship between the nucleotide
sequence in nucleic acids and the amino acid sequence in
proteins
• theories of the origin of life speculate on how such a coding
system might have arisen
Biomolecules (Cont’d)
• Which came first…the chicken or the egg?
• catalytic activity associated with _______________
• coding associated with ____________________
• It has been discovered recently that certain types of RNA have
catalytic activity (ribozymes) and are capable of catalyzing
their own further processing (See Figure 1.7 p.12)
• RNA is now considered by many scientists to have been
the original _____________________________
• it still serves this function in ________________
The “RNA World”
• The appearance of a form of RNA capable of coding
for its own replication was the pivotal point in the
origin of life
• This original RNA both encoded for and catalyzed its
own replication
• In time, this system evolved to encode for the
synthesis of protein catalysts
• Even later, DNA became the primary genetic
material, and RNA took on only an intermediary role
in the synthesis of proteins
• Question: What is the empirical evidence to support
this?
Stages in the Evolution of Self-replicating
RNA Molecules
Theories on the Origin of Life
• A key point in the development of living cells is the
formation of membranes that separate cells from their
environment
• Some theories of the origin of life focus on proteins
• according to one model, proteinoids aggregated to
form microspheres
• Double-Origin theory: the development of a coding
system and the development of catalysis came about
separately
• a combination of the two later in time produced life as
we know it.
• Question: What is the empirical evidence to support
this?
Prokaryotes and Eukaryotes
• ______________: Greek derivation meaning “before
the nucleus”
• single-celled organisms
• include bacteria and cyanobacteria
• _______________: Greek derivation meaning “true
nucleus”
• contain a well-defined nucleus surrounded by a
nuclear membrane
• can be single celled, such as yeasts and Paramecium,
or multicellular, such as animals and plants
Comparison of Prokaryotes and Eukaryotes
A Comparison of a typical animal cell, plant
cell, and prokaryotic cell
• Important organelles
listed in table 1.3
Comparison of Prokaryotes and Eukaryotes
Five Kingdoms, Three Domains
• 5-kingdom system takes into account differences
between prokaryotes and eukaryotes
• Provides classification for eukaryotes that are neither
plants nor animals
• Kingdoms are:
1. _________________________________
2. _________________________________
3. _________________________________
4. _________________________________
5. _________________________________
Five Kingdoms, Three Domains
What is source of energy in cells?
• _______________________ is the ultimate source of
energy for all life on earth
• photosynthetic organisms use ____________ to drive
the energy-requiring synthesis of carbohydrates
• non-photosynthetic organisms consume these
carbohydrates and use them as __________________
• The __________________ of a chemical reaction
• if the change in free energy is _________ (free energy
decreases), the reaction is spontaneous as written
• if the change in ___________ (free energy increases),
the reaction will not occur as written unless energy is
supplied from an external source
How are energy changes measured?
Thermodynamics- branch of science that answers questions
about processes that are energetically favorable
Spontaneity in biochemical reactions
• Free Energy of a System
 G < 0 spontaneous exergonic- energy released
 G= 0 Equilibrium
 G > 0 Nonspontaneous endergonic- energy required
• Life and Thermodynamics
 G=H-TS
 H is heat of a reaction at constant pressure
 S is the change in entropy
 G is the change in free energy
• T is the temperature