Chapter One Biochemistry and the Organization of Cells

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: _________________________________

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