book

force” it is not a subject to studies by usual, immediate observation and
experiments, i.e. it is regarded as incognizable.
The view of the incognoscibility of life is greatly expanded in the
philosophy of science and is known as “agnosticism” (Greek: a — not and
gnosius — knowledge). The term has been introduced by the English
physician and scientist Th. Huxley (1825—1895). This understanding of
life is not shared by the great German writer, poet and natural
philosopher J. W. Goethe (1749—1832). In a letter to one of his
numerous friends he has written:

“Behold: Nature is a living book not understood, but not ununderstandable”.

The followers of the materialistic concept place a state to the material
essence of life, development and alterations of matter and its capacity to be
changed in shape and to pass from one quality into another. According to
them life is a qualitatively new form of the existence of non-living matter,
having cropped up as a result of its evolution under certain circumstances.
The mechanistic understanding of life also undergoes a considerable
development. Its supporters, materialistic in principle, tend to ignore the
qualitatively new properties of the emerged living matter and downsize life
phenomena to purely mechanical, physical and chemical processes. In this
train of thought they strive to liken living organisms to complicated
mechanisms, and in the different epochs and depending on the
achievements of technical sciences their models for comparison have been
different: the exquisitely constructed clocks of the town municipalities, the
steam engines, and in the last few decades — electronic computers which
according to their views can completly replace the human being.
The concept set forward by a considerable number of people that man
can be substituted by cybernetic machines provokes a certain interest from
a biological point of view. At the beginning of the 1960s the “artificial
intellect” project was launched, and after the 1970s the “expert systems”
capable of giving intellectual advices and be the decision-makers
expressing themselves in different languages and dialects (see Alty,
Coombs, 1987; Pierce, Hohne, 1988) have come into fashion.
In its core this trend deserves complete support, since it is on the right
path and helps a lot for the scientific and technical advancement.
Nevertheless a question is raised: is it possible for cybernetic machines, no
matter how complex and perfect they are to make up for the human in an
intellectual respect, i.e. would they be capable of thinking process?
The answer to this question is predetermined by the now existing view
that conclusions and decisions can only be made by computers on the basis
of the information preliminarily encoded in them by their creator — the man.
If, by any chance the new computer generations begin “to think” without
human help, then we would be forced to make a reevaluation of the concept
of the qualitative difference between living and non-living nature.

Origin of Life. Early Ideas

Section 1.2. Man has always been entwined in interrelationships with surrounding nature. At the very dawn of his conscious existence he had contemplated it and with the course of time had got convinced of the presence of non-living, lifeless matter and a stunning variety of animals and plants. This objective reality has urged him to think about where all this has come from, who has created it and at a later stage to make a distinction between the common and the different of these two forms from which the material world is made. At that time microorganisms not only were unknown to man, but he did not even have any suspicion of their existence. He got knowledge of them only after discovery of the microscope.

The common between these two forms is that they are material. This is an undisputed fact that no rational human can deny. More important prove to be the differences between them which have become the reason to accept the notions of the living and non-living matter. What in fact is living matter and what is its origin? This question is of particular importance, and without a scientifically based answer to it, no realistic idea about the objective reality in which living organisms have emerged and are existing can be obtained. The problem of the essence of life and its emergence has occupied mankind since ancient times. At the top of the pyramid of the evolutionary development of living organisms, having become conscious of his own self man could not have bypassed it without taking an interest in its clarification. He is an already thinking being. And the more his knowledge of nature has broadened and his practical capacities have increased with the development of science, the more his interest in this problem has been increasing aiming at its clarification. In ancient times Heraclitus (540—483 B. C.), the Greek materialist and founder of dialectics and later Aristotle (384—322 B. C.) have taught that the essence of things can be understood only when their origin and development are known. The essence of life has more of a philosophical interpretation. It is hardly possible for one to give an exact and thorough definition of the notion of “life” the way the term “matter” has not yet been defined. For the present as most adequate is accepted the one given by V. I. Lenin that “the matter is a philosophical category for designating objective reality existing outside and independently of our consciousness”. As more important here emerges the point of view from which it is perceived. The differences in the point of view have engendered two basic philosophical concepts — the idealistic and the materialistic, which because of their important historical role for the development and clarification of this problem cannot be ignored. The followers of the idealistic concept with all its variations discern in the essence of life a certain “meta-material principle” or “life force” (vis vitalis), and matter is considered only a substance from which living entities are made. And since life is “meta-material” incorporating a “God-like” or “life

“Long ago it became evident that the
key to every biological problem must
finally be sought in the cell; for every
living organism is, or at some time has
been, a cell”.

E. B. Wilson
(The Cell in Development and
Heredity. 3rd ed. Macmillan Inc.,
New York, 1925).

ORIGIN AND EVOLUTION OF THE CELL
CHAPTER 1

The Cell — Life Link
Section 1.1.With the development of biology the view that all living
organisms inhabiting the planet Earth, man including are
independently existing cells or are built up from cells has been finally
confirmed and widely spread. In its universal scope and significance this
achievement can be undisputedly accepted as a pinnacle in biology in
particular and in human knowledge as a whole.
The path leading to that peak was long and extremely hard. It was
marked by embittered battles between various opinions, hypotheses and
theories, proved and refuted by courageous scientific experiments and
decisions which in the end led to its conquering.
The origin of cell is closely related to the generation and evolution of
living matter, i.e. — life, as this unique phenomenon is called. To this
interrelated process in its development in nature and its study by man is
devoted the present Chapter of the book.
It is necessary to state from the very beginning that the formation of
modern concepts of the origin of life, its development and evolution from
lower to higher forms of existence results from the efforts of a great number
of very far-seeing sagacious human minds (thinkers, philosophers,
astronomers, natural scientists, astrophysicists, geochemists, biologists,
cytologists, chemists, biochemists, cosmologists, etc.) since ancient times
till our day. They are so numerous that it is practically impossible all their
names and tributes to be mentioned in only one book, very limited in
volume. That is why only the names of the ones that have played a
significant and at times most decisive role in the process of elucidation of
this exceptionally important problem for humanity will be quoted.

Chapter 4 is of retrospective and perspective character. The aim is to
show how through integration of single cells multicellular organisms have
been formed, as well as how through cloning of separate somatic cells from
multicellular organisms developed in tissue and cell cultures many-cell
organisms can be reproduced.
The unclarified key problems in the study of the cell up to now such as
the pre-cell evolution, protein synthesis (especially in the early stages of life
emergence), the genetic code evolution, the problem of the relationships
between proteins and nucleic acids in the chromosomes, gene expression,
the causes for triggering or retention of cell division, molecular bases of
mutation changes and the in vivo organization of the cell organelles are
symbolically designated as “white spots” in biology. This is to show how far
from solving these problems we are at present though not in the least
intending to say that there are no intensive studies going on in these fields.
On some issues I have expressed opinions differing from the officially
accepted ones, sometimes unsupported by experimental data. This will
inevitably cause disapproval and disagreement by some readers,
predominantly experts in the given field. Although I place the experiment
above all, I admit that scientific knowledge can be supplemented by
speculative suppositions when it is based on solid logic in the interpretation
of the results obtained before. I do share the said of Albert Einstein that
“Science can progress on the basis of error as long as it is not trivial” (cited
by Koshland, 1988).
The problems in the book encompass a long historical period — from
ancient times till our day. Because of this, some of the early publications
with considerable contributions whose authors have acquired great publicity
are cited from the literature. Everything of course was subjected to most
precise scrutiny.
The book is designed for a broad range of readers — biologists,
cytologists, geneticists, biochemists, young scientists, students, etc. It
would also be of help to anyone interested in his/her origin, evolution and
position in nature. I would be very grateful for all objective and well-intended remarks.

Institute of Genetics, Sofia Nicolay Nicolov
September 1999

PREFACE

At the end of XX century biology is a very well-developed science. The
information flux in this field of human knowledge has attained such
dimensions that it is hard to encompass, systematize and analyze it even
by the help of modern computer systems. The links among the numerous
biological branches have been considerably weakened regarding the
general biological problems as a result from the narrow specialization of
studies which sometimes leads to erroneous conclusions and concepts.
The idea to write a book giving a generalized notion of the great
achievements and unclarified problems in biology related to the conditions and
prerequisites for the origination of living matter, the formation of the cell as a
biological unit, its chemical and organization structure, various functions,
modes and mechanisms of self-reproduction, heredity and variability, its
participation in the building of the multicellular organisms, cloning, etc. has not
abandoned me for more than a decade. It lay for a long time buried deep in my
consciousness unrealized because of the risks and difficulties its practical
realization poses, since a lot of the treated problems are still not clarified to the
full and have caused “exacerbated” debates.
The book comprises 4 chapters. The problems treated in them are laid
out and considered (as much as it is possible) in an evolutionary and
historical aspect corresponding to their natural development and their study
by man.
Chapter 1 is devoted to the origin and evolution of the cell which has
consolidated itself as a mode and form for the survival of the living matter
already arisen. Such issues as its transfer from space (the ,,panspermia”
hypothesis), the attempts for abiogenic synthesis of organic compounds in
laboratory conditions, the more significant findings of fossils of unicellular
organisms in earth layers and finally the question of whether we are alone
in the Universe are treated in this chapter.
Chapter 2 considers the cell as the basic structural and functional
biological unit. It starts from its discovery by man, the initial and latest
concepts for its essence, structure and functions. Special attention is paid
to the major building compounds of the cells — proteins (polypeptides),
nucleic acids (polynucleotides) and carbohydrates (polysaccharides), the
transfer of heredity in the offspring, cell organelles, mutation changes and
the endosymbiotic organization of the eukaryotic cells.
Chapter 3 treats the discovery, biological essence, modes and types
of cell division, i.e. self-reproduction of the cells. A major role in this
process is played by the nucleus or its equivalent (the nucleoid), and also
by the division spindle which is the phenomenon making the difference
between the eukaryotic and prokaryotic cells. The problems of biological
aging and neoplasms are not bypassed.

FOREWORD

I hope sincerely that the book “Cell and Cell Division”, kindly offered
to your attention, will rouse interest in many readers, mostly
biologists, cytologists, geneticists, biochemists, scientists, students,
and others. Grounds for this give its subjects as a whole. The book is
well arranged, the topics are logically connected and the ideas, which
the author has considered, are set out and examined from
evolutionary and historical point of view representing their
development in the nature and the human knowledge of them.
In this way the book presents a generalized scientific notion
about the conditions and prerequisites which have brought about the
emergence of living matter, its formation, evolution and development
in cellular structures, i.e. cells – the basic structural and functional
biological units from which, via integration, multicellular organisms
were developed. Besides, an explanation is given how multicellular
organisms can be reproduced by means of cloning of single
vegetative cells, grown in tissue and cellular cultures. Since the
question about life’s origin and its existence is of exceptional interest
the author has searched for an answer in the results from the
researches on coacewate drops, the experiments on abiogenic
synthesis of organic compounds in laboratory conditions, the more
essential finds of fossils in the earth layers, the space flights in the
Solar system, and the possibility of its conveyance by other celestial
bodies.

Great attention is paid to the basic components which take part in
the construction and functioning of cells, transference of hereditary
traits to the next generations, cellular organelles, mutation changes,
endosymbiotic organization of eukaryotic cells, biological aging and
neoplasms, cloning, and others.
Special attention is paid to the cell division as a mechanism for
self-reproduction of cells and for ensuring the succession in living
organisms existence. The key to elucidation of this problem has been
sought in revealing the modes of its realization at a time. In this
respect a contribution of the author is the established by him
asynchronous nuclear and cell division as natural biological process,
which until recently were thought to be “exceptions” or “unusual”
phenomena contradicting the generally accepted rule of synchronous
division

Along with the many remarkable discoveries, presented in
objective way, and great achievements in biology and genetics, the
author has brought up a lot of intricate and tangled questions in this
field of the human knowledge. He has sought for answers to some of
them and given his own opinions which differ from the widely
accepted and prevalent ones. This approach in searching for
scientific truth deserves approval because it rouses thoughts which
could help its elucidation.

A. Mehandjiev

2.8. Structural Organization of Cells and Cell Organelles
Cell Wall and Cell Envelope
Nucleus
Cell Centre
Endoplasmic Reticulum
Golgi Apparatus (Complex)
Mitochondria
Chloroplasts
Ribosomes
Cytoskeleton
2.9. Mutation Changes — Basic Mechanism for Augmentation of the
Gene Fund and Diversity of Living Organisms
Prerequisites for Generation of Idea of the Mutation Changes
Mutation Theory
Classification of the Mutations
Molecular Bases and Mechanisms of the Mutation Changes
Reparation Processes
2.10. Endosymbiotic Organization of the Eukaryotic Cells
2.11. Are the Viruses Cells?
CHAPTER 3. CELL DIVISION
3.1. Biological Essence and Importance of Cell Division
3.2. Discovery and Insight in the Essence of Cell Division
3.3. The Nucleus or the Nuclear Equivalent (Nucleoid) — Obligatory and
Irreplaceable Component of Each Cell
3.4. Modes and Types of Cell Division
3.5. Causes for Starting or Stopping the Cell Division
3.6. Biological Aging and Neoplasms
CHAPTER 4. FROM SINGLE CELLS TO MULTICELLULAR ORGANISMS. CLONING
CONCLUSION
Appendix 1
Appendix 2
REFERENCES
SUBJECT INDEX
AUTHOR INDEX

CONTENTS

PREFACE
CHAPTER 1. ORIGIN AND EVOLUTION OF THE CELL
1.1. The Cell — Life Link
1.2. Origin of Life. Early Ideas
1.3. Formation of Scientific Consepts on the Origin of Life
1.4. Attempts for Abiogenic Synthesis of Organic Compounds
1.5. The “Panspermia” Hypothesis
1.6. Evolution of the Cell
Pre-Cell Evolution
Can Proteins Self-Reproduce?
Is the Genetic Code Universal and Invariable?
Metabolism
1.7. Tracing Life on the Earth
1.8. Are We Alone in the Universe?
CHAPTER 2. THE CELL — BASIC STRUCTURAL AND FUNCTIONAL BIOLOGICAL SYSTEM
2.1. Discovery of the Cell and First Notions of Its Essence and Structure
2.2. Cell Theory
2.3. Later Concepts on the Structural Organization of the Cell.
Discovery of Some Its Organelles
2.4. Discovery of the Discrete Factors of Heredity. The Experiments
of Gregor Mendel
Monohybrid Crossing
Dihybrid Crossing
Intermediary Inheritance of the Features
Polyhybrid Crossing
2.5. Discovery of Nuclein and Elucidation of the Biological Role of
Nucleic Acids
2.6. Chromosome Theory of the Heredity and Organization of the
Genome
2.7. Modern Concepts About the Structure, Functions and Self-Reproduction of Cells
Proteins
Nucleic Acids
The Watson and Crick Model
Some Deviations from the Watson and Crick Model
Carbohydrates

This book is dedicated to the scientific truth and to all my
friends, colleagues and readers, who believe that I have
made efforts to present objectively the problems and
facts found place in it

Nicolay N. Nicolov

CELL and CELL DIVISION

English Translation from the Bulgarian Edition by Orlin Ivanov, D. Sc.

Sofia. 2001

Professor Marin Drinov Academic Publishing House