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First Edition: 2021 ISBN: 978-93-88901-16-1 Copyright reserved by the author Publication, Distribution and Promotion Rights reserved by Bhumi Publishing, Nigave Khalasa, Kolhapur Despite every effort, there may still be chances for some errors and omissions to have crept in inadvertently. No part of this publication may be reproduced in any form or by any means, electronically, mechanically, by photocopying, recording or otherwise, without the prior permission of the publishers. The views and results expressed in various articles are those of the authors and not of editors or publisher of the book. Published by: Bhumi Publishing, Nigave Khalasa, Kolhapur 416207, Maharashtra, India Website: www.bhumipublishing.com E-mail: [email protected] Book Available online at: https://www.bhumipublishing.com/books/ Preface to the first edition Cytogenetics, in cell biology, field that deals with chromosomes and their inheritance, particularly as applied to medical genetics. Chromosomes are microscopic structures found in cells, and malformations associated with them lead to numerous genetic diseases. Chromosomal analysis has steadily improved in precision and resolution, and that has led to improvements in the diagnosis of various genetic diseases in all areas of medicine. The study of chromosomes begins with the extraction of intact chromosomes from live cells. Chromosomal analyses often make use of white blood cells (T-lymphocytes), which multiply quickly under cell culture conditions. Chromosomes may also be extracted from skin cells, bone marrow cells, or fetal cells (by amniocentesis or chorionic villus sampling). The book is written in simple language so that the students can easily grasp the matter. Some important terms has been incorporated, so that the students may search the useful related for competitive examinations. In the recent years included in the syllabus of almost all Indian Universities in various subjects of Biology or Life Sciences as an independent evergreen subject. Exponential growth in many areas of basic fundamentals made it necessary in some cases to write several chapters on the same topic which was covered in a single chapter in the earlier book. Similarly, in the present volume, separate new chapters have been written on topics which in the earlier title either did not figure at all or were each covered very briefly as a part of a chapter. In the present book, for instance in separate chapters have been written on new topics. The students of Biology at the post graduate (P.G.) under graduate (U.G.) levels needed to the recent Global changes and developments. This book is intended to be an accessible introduction to the cell biology and cytogenetics for junior or senior undergraduate students who have already had an introduction to biological sciences. This engaging and stimulating text focuses on detailed aspects in cell biology. - Dr. Mandaloju Venkateshwarlu ACKNOWLEDGEMENT The world is a better place thanks to people who want to develop and lead others. What makes it even better are people who share the gift of their time to mentor future leaders. Thank you to everyone who strives to grow and help others grow. It is the business version of The Lion King song, “Circle of Life.” To all the individuals I have had the opportunity to lead, be led by, or watch their leadership from afar, I want to say thank you for being the inspiration and foundation for The Leadership Kakatiya University, Botany Department. Without the experiences and support from my peers and team at Ultimate Software, this book would not exist. You have given me the opportunity to lead a great group of individuals—to be a leader of great leaders is a blessed place to be. Thank you to friends and colleagues of my Department of Botany, Kakatiya university. Several of my students in the laboratory helped me either in writing some of the chapters or in preparing the list of references and appendix given at the end of this volume. There may also be errors and omissions of technical nature, since in a vast and fast expanding subject like Botany Biotechnology; one cannot claim to have known everything, despite his best efforts. I am thankful to Department Head, BOS, Staff and Research Scholars (Botany) my family members, inspiration and cooperation my wife and children’s (M. Hamsini) Teachers, Friends, Students and Well-Wishers (Dursheti Sai Charan, M.B.A., Certified Microsoft Office and Windows Specialist). I hope that this book will be useful to students in Life Sciences. Having an idea and turning it into a book is as hard as it sounds. The experience is both internally challenging and rewarding. I especially want to thank the individuals that helped make this happen. Complete thanks to Family members and relatives who have supported in making the book. - Dr. Mandaloju Venkateshwarlu No. Title Page No. 1 Plant Cell 1 – 10 2 Nucleus Structure 11 – 42 3 Chromosome Morphology 43 – 59 4 Special Types of Chromosomes 60 – 64 5 Cell Division 65 – 77 6 Mendel’s Laws 78 – 101 7 Linkages 102 – 118 8 Mutations 119 – 166 9 Gene Expression 167 – 194 10 Extra Nuclear Genes 195 – 211 Cell Biology and Cytogenetics (Volume – 1) (ISBN: 978-93-88901-16-1) Ultra structure of cell wall Presence of cell wall is an identifying character of plant cell as it is absent in animal cell. This wall may be absent in some lower plants and cells taking part in the reproduction. For example, cell wall is not found in gametes and zoospores, in lower fungi (slime moulds) as Synchitrium which causes wart disease of potato, and Plasmodiophore. Bacteria and fungi are placed in plant kingdom because they contain cell wall. Cell wall is not found in Mycoplasma.Cell wall is outermost, non living rigid and freely permeable structure. Figure 1.1: Structure of an animal cell. In this generalized diagram of an animal cell, the plasma membrane encases the cell, which contains the cytoskeleton and various cell organelles and interior structures suspended in a semifluid matrix called the cytoplasm. Some kinds of animal cells possess fingerlike projections called microvilli. Other types of eukaryotic cells- for example, many protist cells-may possess flagella, which aid in movement, or cilia, which can have many different functions During cytokinesis in vesicles of Golgi complex become aligned at the equatorial plate or cell plate or phragmoplast (spindle fibre complex). The cell plate forms when Golgi vesicles and endoplasmic reticulum cisternae aggregate in the spindle mid zone area of a dividing cell. The aggregation is organized by the phragmoplast; a complex assembly of microtubules, membranes and the vesicles that form during late anaphase or early telophase. The membranes of the vesicles fuse with each other and with the lateral plasma membrane, to become the new plasma membrane separating the daughter cells. By some physical and chemical changes in cell plate an intercellular amorphous substance functions as cementing material 1 Bhumi Publishing, India between two cells. It is made up of calcium and magnesium pectate. This layer is called middle lamella. Middle lamella is the outermost layer of the cell wall. Plane of cell wall formation is determined by microtubules. The cell formation is always perpendicular to spindle fibres (Fig. 1.4). The characteristic softening of fruit during ripening is mainly due to increase in the solubility of middle lamella. Primary cell wall Protoplasm deposit some substance on the middle lamella due to which a soft delicate plastic wall is formed.This is called primary cell wall. Primary wall occurs just below the middle lamella and it appears first in the ontogeny along with the middle lamella. The primary wall consists of cellulose micro- fibrils which are embedded in a highly hydrated amorphous matrix. Approximately 100 long chains of cellulose make up an elementary fibril or micelle. Approximately 20 elementary fibrils constitute a micro fibril. 250 micro-fibrils are interwoven to form a fibril and these fibrils form a network. The matrix consists of two major groups of polysaccharides usually called hemicellulose and pectins plus a small amount of structural proteins (Fig. 1.3). Cellulose micro-fibrils are relatively stiff structure that contributes to the strength and structural bias of the cell wall. Cell wall is very stable and only breaks down at specific times in development, such as senescence and abscission. Cellulose has high tensile strength, equivalent that of steel. It is insoluble, chemically stable and relatively imrnune to chemical and enzymatic attack. These properties make cellulose an excellent structural material for building a strong cell wall. Cellulose micro-fibrils are synthesized by large ordered protein complexes called particles rosettes or terminal complexes that are embedded in the plasma membrane. These structures are believed to contain many units of cellulose synthase. In fungi, fibrils are made up of chitin. Hemicelluloses are a heterogenous group of polysaccharides and are flexible, in primary cell wall of dicotyledons; the most abundant hemicellulose is xyloglucan. In cereal grasses it is β- D-glucan and arbinoxylon. Cellulose Micelle Micro-fibril Fibrils Network Like the hemicelluloses, pectins constitute a heterogenous group of polysaccharides, characteristically containing acidic sugars such as galacturonic acid and neutral sugars such as rhamnose, galactose and arabinose. Pectins are the most soluble of the wall polysaccharides, they can be extracted with hot water or with calcium chelators. Pectin forms hydrated gels in which the charged carboxyl groups [COO-] of neighbouring pectin molecules are ionically linked together via Ca++. 2 Cell Biology and Cytogenetics (Volume – 1) (ISBN: 978-93-88901-16-1) Figure 1.2: Structure of a plant cell. Most mature plant cells contain large central vacuoles, which occupy a major portion of the internal volume of the cell, and organelles called chloroplasts, withinwhichphotosynthesis takes place. The cells of plants, fungi, and some protists have cell walls, although thecomposition of the walls varies among the groups.

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