CELL BIOLOGY PRACTICAL REPORT-Ukoro Frank (original) (raw)
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Cell biology also known as cytology. It deals with cells and its organelles. Inside this document you find curious of yours about cells and how they act like independent livings within bodies of living organisms. Preparation of this lecture notes has took much effort as needs high understanding in science of biology. Cells are important parts of life and without them life can be impossible. Understanding sciences like cytology, histology, genetics, biochemistry, molecular biology, are essential sciences to know are linked to knowledge of cells. During preparation of this lecture notes, content of module of cell biology taught in biomedical sciences courses in INES-Ruhengeri at undergraduate level has been used. A part from this content different source has been used to study each topic with much attention. Books of cytology, molecular biology, medical genetics, biochemistry, and different journals related to this module have been contributed to produce this lecture notes. This lecture notes can be a good asset in different areas of biological and biomedical sciences. They can help biomedical laboratory scientists to understand the role of cell in life of living things. Ideal International E-Publication www.isca.co.in iv Lecture notes: Cell Biology -Dr. Callixte Yadufashije
Cell Division in Spirogyra. II. Cytokinesis
Journal of Phycology, 1969
Cytokinesis in cells of Spirogyra sp. was studied with both light and electron microscopes. Early formation of the cross wall was achieved by annular ingrowth of a septum; the cross wall was completed by a phragmoplast containing Golgi vesicles, longitudinally aligned microtubules, and associated electron-dense material. Spirogyra may represent an intermediate stage in the evolution of the phragmoplast seen in higher plants.
Cell Division: The process through which new cells are formed from pre-existing cells.in other words division of chromosomes and cytoplasm of cell into two daughter cells. Cell division is process of cell multiplication.it is an important process for growth and development of organism and repair of damaged parts of an organism. The cell undergoing cell division is called parental cell and one which is result of cell division is called daughter cell. In prokaryotes, Cell division occurs by a binary fission. In eukaryotes, cell division is divided into two stages ie., mitosis and meiosis. Types of cell division: three types cell division observed are binary fission, mitosis and meiosis Events of cell division: Karyokinesis and Cytokinesis Karyokinesis refers to division of nucleus, it is the division of chromosomes of cell into two groups which give rises to two daughter nuclei. This term was coined by Schleicher in 1878. Cytokinesis refers to the division of cytoplasm into two halves to produce two daughter cells. Definition of Cell cycle: The sequence of events by which a cell duplicates its genome, synthesises the other constituents of the cell and eventually divides into two daughter cells is termed cell cycle. It can be defined as the entire sequence of events happening from the end one nuclear division to the beginning of the next. Howard and Pelec (1953) classified cell cycle into four stages. Phases of cell cycle: Interphase: The term was coined by Lundergardh in 1912, it usually longest part of the cell cycle. In this phase cell mass increases, number of cytoplasmic components doubles and DNA is duplicated. Each chromosome replicates to produce two sister chromatids, which remains attached each other at centromere. Centrioles replicate in animal cells and it's a metabolically active stage. Interphase is divided into 3shorter stages. G1 (First gap), S (Synthesis) and G2 (Second gap).