(Redirected from Cytology)
'Cell biology' (also called 'cellular biology' or formerly 'cytology', from the
Greek ''kytos'', "container") is an
academic discipline that studies
cells. This includes their
physiological properties, their structure, the
organelles they contain, interactions with their environment, their
life cycle,
division and
death. This is done both on a
microscopic and
molecular level.
Cell biology research extends to both the great diversity of single-celled organisms like
bacteria and the many specialized cells in multicellular
organisms like
humans.
Knowing the composition of cells and how cells work is fundamental to all of the
biological sciences. Appreciating the similarities and differences between cell types is particularly important to the fields of cell and
molecular biology. These fundamental similarities and differences provide a unifying theme, allowing the
principles learned from studying one cell type to be extrapolated and generalized to other cell types.
Research in cell biology is closely related to
genetics,
biochemistry,
molecular biology and
developmental biology.
Understanding cells in terms of their molecular components.
Processes
Movement of proteins
Proteins (red and green stain) at different locations in a cell.
Every cell typically contains hundreds of different kinds of
macromolecules that function together to generate the behavior of the cell. Each type of
protein is usually sent to a particular part of the cell. An important part of cell biology is the investigation of molecular mechanisms by which proteins are moved to different places inside cells or secreted from cells.
Most
proteins are synthesized by
ribosomes in the
cytoplasm. This process is also known as
protein biosynthesis or simply
protein translation. Some proteins, such as those to be incorporated in membranes
membrane proteins, are transported into the ER or
endoplasmic reticulum during synthesis and further processed in the
Golgi apparatus. From the Golgi, membrane proteins can move to the
plasma membrane, to other subcellular compartments or they can be secreted from the cell. The ER and Golgi can be thought of as the "membrane protein synthesis compartment" and the "membrane protein processing compartment", respectively. There is a semi-constant flux of proteins through these compartments. ER and Golgi-resident proteins associate with other proteins but remain in their respective compartments. Other proteins "flow" through the ER and Golgi to the plasma membrane.
Motor proteins transport membrane protein-containing vesicles along
cytoskeletal tracks to distant parts of cells such as
axon terminals.
Some proteins that are made in the cytoplasm contain
structural features that target them for transport into
mitochondria or the
nucleus. Some mitochondrial proteins are made inside mitochondria and are coded for by mitochondrial DNA. In plants,
chloroplasts also make some cell proteins.
Extracellular and cell surface proteins destined to be degraded can move back into intracellular compartments upon being incorporated into
endocytosed vesicles. Some of these vesicles fuse with
lysosomes where the proteins are broken down to their individual
amino acids. The degradation of some membrane proteins begins while still at the cell surface when they are cleaved by
secretases. Proteins that function in the cytoplasm are often degraded by
proteasomes.
Other cellular processes
★
Cell division - The origin of new cells.
★
Cell signaling - Regulation of cell behavior by signals from outside.
★
Active transport and
Passive transport - Movement of molecules into and out of cells.
★
Adhesion - Holding together cells and tissues.
★
Transcription and
mRNA splicing - gene expression.
★ Cell movement:
Chemotaxis,
Contraction,
cilia and
flagella
★
DNA repair and
Cell death
★
Metabolism:
Glycolysis,
respiration,
Photosynthesis
★
Autophagy - The process whereby cells "eat" their own internal components or microbial invaders.
Techniques
★
Microscopy and
Immunostaining
★
Gene knockdown and
Transfection
★
Cell culture and
Radioactive tracers
★
PCR and
In situ hybridization
★
DNA microarray screens of gene expression
★
Computational genomics approaches are used to find patterns in genomic information
[1]
Purification of cells and their parts
Purification of cells and their parts is achieved in the following ways:
★
Flow cytometry
★
Cell fractionation
★
★ Release of cellular organelles by disruption of cells.
★
★ Separation of different organelles by
centrifugation.
★ Proteins extracted from
cell membranes by
detergents and
salts or other kinds of chemicals.
★
Immunoprecipitation
Some structures inside cells
Electronmicrograph.
★
Organelle - term used for major subcellular structures
★
Chloroplast - key
organelle for
photosynthesis
★
Cilia - motile
microtubule-containing structures of
eukaryotes
★
Cytoplasm - contents of the main fluid-filled space inside cells
★
Cytoskeleton - protein filaments inside cells
★
Ribosome -
RNA and protein complex required for protein synthesis in cells
★
Endoplasmic reticulum - major site of membrane
protein synthesis
★
Flagella - motile structures of
bacteria,
archaea and eukaryotes
★
Golgi apparatus - site of protein
glycosylation in the
endomembrane system
★
Membrane lipid and
protein barrier
★
Lipid bilayer - fundamental organizational structure of
cell membranes
★
Vesicle - small membrane-bounded spheres inside cells
★
Mitochondrion - major energy-producing organelle
★
Nucleus - holds most of the
DNA of eukaryotic cells
See also
★
Cell disruption
★
Important publications in cell biology
★
Institute of Molecular and Cell Biology
★
The American Society for Cell Biology
Notable cell biologists
★
Anton van Leeuwenhoek
★
Günter Blobel
★
Marc Kirschner
★
Peter Agre
★
Keith R. Porter
★
Ira Mellman
★
Paul Nurse
★
H. Robert Horvitz
★
Christian de Duve
★
Edmund Beecher Wilson
★
Peter D. Mitchell
★
Michael Swann
★
George Emil Palade
★
Geoffrey M. Cooper
References
★
1. Cristianini, N. and Hahn, M. ''Introduction to Computational Genomics'', Cambridge University Press, 2006. (ISBN-13: 9780521671910 | ISBN-10: 0521671914)
External links
★
American Society for Cell Biology
★
British Society for Cell Biology
★
Cells Alive
★
BMC Cell Biology - online journal, open access
★
Journal of Cell Biology - older issues free
★
Journal of Cell Science - older issues free
★
Cell Biology - School and University - graphics
★
Nature Reviews Molecular Cell Biology (
journal home)
★
The Virtual Library of Biochemistry and Cell Biology
★
Centre of the Cell online resource
Wikiversity
has learning resources related to this subject:''''
Online cell biology textbooks
★ ''
Molecular Biology of the Cell'' fourth edition, edited by Bruce Alberts (2002) published by Garland Science.
★ ''
Molecular Cell Biology'' fourth edition, edited by Harvey Lodish (2000) published by W. H. Freeman and Company.
★ ''
The Cell - A Molecular Approach'' second edition, by Geoffrey M. Cooper (2000) published by Sinauer Associates.
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