Thu . 18 Nov 2018

Cell (biology)

cell biology international, cell biology pdf
The cell from Latin cella, meaning "small room" is the basic structural, functional, and biological unit of all known living organisms A cell is the smallest unit of life that can replicate independently, and cells are often called the "building blocks of life" The study of cells is called cell biology

Cells consist of cytoplasm enclosed within a membrane, which contains many biomolecules such as proteins and nucleic acids Organisms can be classified as unicellular consisting of a single cell; including bacteria or multicellular including plants and animals While the number of cells in plants and animals varies from species to species, humans contain more than 10 trillion 1012 cells Most plant and animal cells are visible only under a microscope, with dimensions between 1 and 100 micrometres

The cell was discovered by Robert Hooke in 1665, who named the biological unit for its resemblance to cells inhabited by Christian monks in a monastery Cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all living organisms, that all cells come from preexisting cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells Cells emerged on Earth at least 35 billion years ago


  • 1 Anatomy
    • 11 Prokaryotic cells
    • 12 Eukaryotic cells
  • 2 Subcellular components
    • 21 Membrane
    • 22 Cytoskeleton
    • 23 Genetic material
    • 24 Organelles
      • 241 Eukaryotic
      • 242 Eukaryotic and prokaryotic
  • 3 Structures outside the cell membrane
    • 31 Cell wall
    • 32 Prokaryotic
      • 321 Capsule
      • 322 Flagella
      • 323 Fimbria
  • 4 Cellular processes
    • 41 Growth and metabolism
    • 42 Replication
    • 43 Protein synthesis
    • 44 Movement or motility
  • 5 Multicellularity
    • 51 Cell specialization
    • 52 Origin of multicellularity
  • 6 Origins
    • 61 Origin of the first cell
    • 62 Origin of eukaryotic cells
  • 7 History of research
  • 8 See also
  • 9 References
  • 10 Bibliography
  • 11 External links
    • 111 Textbooks


Comparison of features of prokaryotic and eukaryotic cells
Prokaryotes Eukaryotes
Typical organisms bacteria, archaea protists, fungi, plants, animals
Typical size ~ 1–5 µm ~ 10–100 µm
Type of nucleus nucleoid region; no true nucleus true nucleus with double membrane
DNA circular usually linear molecules chromosomes with histone proteins
RNA/protein synthesis coupled in the cytoplasm RNA synthesis in the nucleus
protein synthesis in the cytoplasm
Ribosomes 50S and 30S 60S and 40S
Cytoplasmic structure very few structures highly structured by endomembranes and a cytoskeleton
Cell movement flagella made of flagellin flagella and cilia containing microtubules; lamellipodia and filopodia containing actin
Mitochondria none one to several thousand
Chloroplasts none in algae and plants
Organization usually single cells single cells, colonies, higher multicellular organisms with specialized cells
Cell division binary fission simple division mitosis fission or budding
Chromosomes single chromosome more than one chromosome
Membranes cell membrane Cell membrane and membrane-bound organelles

Cells are of two types, eukaryotic, which contain a nucleus, and prokaryotic, which do not Prokaryotes are single-celled organisms, while eukaryotes can be either single-celled or multicellular

Prokaryotic cells

Main article: Prokaryote Structure of a typical prokaryotic cell

Prokaryotic cells were the first form of life on Earth, characterised by having vital biological processes including cell signaling and being self-sustaining They are simpler and smaller than eukaryotic cells, and lack membrane-bound organelles such as the nucleus Prokaryotes include two of the domains of life, bacteria and archaea The DNA of a prokaryotic cell consists of a single chromosome that is in direct contact with the cytoplasm The nuclear region in the cytoplasm is called the nucleoid Most prokaryotes are the smallest of all organisms ranging from 05 to 20 µm in diameter

A prokaryotic cell has three architectural regions:

  • Enclosing the cell is the cell envelope – generally consisting of a plasma membrane covered by a cell wall which, for some bacteria, may be further covered by a third layer called a capsule Though most prokaryotes have both a cell membrane and a cell wall, there are exceptions such as Mycoplasma bacteria and Thermoplasma archaea which only possess the cell membrane layer The envelope gives rigidity to the cell and separates the interior of the cell from its environment, serving as a protective filter The cell wall consists of peptidoglycan in bacteria, and acts as an additional barrier against exterior forces It also prevents the cell from expanding and bursting cytolysis from osmotic pressure due to a hypotonic environment Some eukaryotic cells plant cells and fungal cells also have a cell wall
  • Inside the cell is the cytoplasmic region that contains the genome DNA, ribosomes and various sorts of inclusions The genetic material is freely found in the cytoplasm Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular Linear bacterial plasmids have been identified in several species of spirochete bacteria, including members of the genus Borrelia notably Borrelia burgdorferi, which causes Lyme disease Though not forming a nucleus, the DNA is condensed in a nucleoid Plasmids encode additional genes, such as antibiotic resistance genes
  • On the outside, flagella and pili project from the cell's surface These are structures not present in all prokaryotes made of proteins that facilitate movement and communication between cells

Eukaryotic cells

Main article: Eukaryote Structure of a typical animal cell Structure of a typical plant cell

Plants, animals, fungi, slime moulds, protozoa, and algae are all eukaryotic These cells are about fifteen times wider than a typical prokaryote and can be as much as a thousand times greater in volume The main distinguishing feature of eukaryotes as compared to prokaryotes is compartmentalization: the presence of membrane-bound organelles compartments in which specific metabolic activities take place Most important among these is a cell nucleus, an organelle that houses the cell's DNA This nucleus gives the eukaryote its name, which means "true kernel nucleus" Other differences include:

  • The plasma membrane resembles that of prokaryotes in function, with minor differences in the setup Cell walls may or may not be present
  • The eukaryotic DNA is organized in one or more linear molecules, called chromosomes, which are associated with histone proteins All chromosomal DNA is stored in the cell nucleus, separated from the cytoplasm by a membrane Some eukaryotic organelles such as mitochondria also contain some DNA
  • Many eukaryotic cells are ciliated with primary cilia Primary cilia play important roles in chemosensation, mechanosensation, and thermosensation Cilia may thus be "viewed as a sensory cellular antennae that coordinates a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary motility or alternatively to cell division and differentiation"
  • Motile cells of eukaryotes can move using motile cilia or flagella Motile cells are absent in conifers and flowering plants Eukaryotic flagella are less complex than those of prokaryotes

Subcellular components

Illustration depicting major structures inside a eukaryotic animal cell

All cells, whether prokaryotic or eukaryotic, have a membrane that envelops the cell, regulates what moves in and out selectively permeable, and maintains the electric potential of the cell Inside the membrane, the cytoplasm takes up most of the cell's volume All cells except red blood cells which lack a cell nucleus and most organelles to accommodate maximum space for hemoglobin possess DNA, the hereditary material of genes, and RNA, containing the information necessary to build various proteins such as enzymes, the cell's primary machinery There are also other kinds of biomolecules in cells This article lists these primary components of the cell, then briefly describes their function


Main article: Cell membrane

The cell membrane, or plasma membrane, is a biological membrane that surrounds the cytoplasm of a cell In animals, the plasma membrane is the outer boundary of the cell, while in plants and prokaryotes it is usually covered by a cell wall This membrane serves to separate and protect a cell from its surrounding environment and is made mostly from a double layer of phospholipids, which are amphiphilic partly hydrophobic and partly hydrophilic Hence, the layer is called a phospholipid bilayer, or sometimes a fluid mosaic membrane Embedded within this membrane is a variety of protein molecules that act as channels and pumps that move different molecules into and out of the cell The membrane is said to be 'semi-permeable', in that it can either let a substance molecule or ion pass through freely, pass through to a limited extent or not pass through at all Cell surface membranes also contain receptor proteins that allow cells to detect external signaling molecules such as hormones


Main article: Cytoskeleton A fluorescent image of an endothelial cell Nuclei are stained blue, mitochondria are stained red, and microfilaments are stained green

The cytoskeleton acts to organize and maintain the cell's shape; anchors organelles in place; helps during endocytosis, the uptake of external materials by a cell, and cytokinesis, the separation of daughter cells after cell division; and moves parts of the cell in processes of growth and mobility The eukaryotic cytoskeleton is composed of microfilaments, intermediate filaments and microtubules There are a great number of proteins associated with them, each controlling a cell's structure by directing, bundling, and aligning filaments The prokaryotic cytoskeleton is less well-studied but is involved in the maintenance of cell shape, polarity and cytokinesis The subunit protein of microfilaments is a small, monomeric protein called actin The subunit of microtubules is a dimeric molecule called tubulin Intermediate filaments are heteropolymers whose subunits vary among the cell types in different tissues But some of the subunit protein of intermediate filaments include vimentin, desmin, lamin lamins A, B and C, keratin multiple acidic and basic keratins, neurofilament proteins NF - L, NF - M

Genetic material

Two different kinds of genetic material exist: deoxyribonucleic acid DNA and ribonucleic acid RNA Cells use DNA for their long-term information storage The biological information contained in an organism is encoded in its DNA sequence RNA is used for information transport eg, mRNA and enzymatic functions eg, ribosomal RNA Transfer RNA tRNA molecules are used to add amino acids during protein translation

Prokaryotic genetic material is organized in a simple circular DNA molecule the bacterial chromosome in the nucleoid region of the cytoplasm Eukaryotic genetic material is divided into different, linear molecules called chromosomes inside a discrete nucleus, usually with additional genetic material in some organelles like mitochondria and chloroplasts see endosymbiotic theory

A human cell has genetic material contained in the cell nucleus the nuclear genome and in the mitochondria the mitochondrial genome In humans the nuclear genome is divided into 46 linear DNA molecules called chromosomes, including 22 homologous chromosome pairs and a pair of sex chromosomes The mitochondrial genome is a circular DNA molecule distinct from the nuclear DNA Although the mitochondrial DNA is very small compared to nuclear chromosomes, it codes for 13 proteins involved in mitochondrial energy production and specific tRNAs

Foreign genetic material most commonly DNA can also be artificially introduced into the cell by a process called transfection This can be transient, if the DNA is not inserted into the cell's genome, or stable, if it is Certain viruses also insert their genetic material into the genome


Main article: Organelle

Organelles are parts of the cell which are adapted and/or specialized for carrying out one or more vital functions, analogous to the organs of the human body such as the heart, lung, and kidney, with each organ performing a different function Both eukaryotic and prokaryotic cells have organelles, but prokaryotic organelles are generally simpler and are not membrane-bound

There are several types of organelles in a cell Some such as the nucleus and golgi apparatus are typically solitary, while others such as mitochondria, chloroplasts, peroxisomes and lysosomes can be numerous hundreds to thousands The cytosol is the gelatinous fluid that fills the cell and surrounds the organelles


Human cancer cells with nuclei specifically the DNA stained blue The central and rightmost cell are in interphase, so the entire nuclei are labeled The cell on the left is going through mitosis and its DNA has condensed
  • Cell nucleus: A cell's information center, the cell nucleus is the most conspicuous organelle found in a eukaryotic cell It houses the cell's chromosomes, and is the place where almost all DNA replication and RNA synthesis transcription occur The nucleus is spherical and separated from the cytoplasm by a double membrane called the nuclear envelope The nuclear envelope isolates and protects a cell's DNA from various molecules that could accidentally damage its structure or interfere with its processing During processing, DNA is transcribed, or copied into a special RNA, called messenger RNA mRNA This mRNA is then transported out of the nucleus, where it is translated into a specific protein molecule The nucleolus is a specialized region within the nucleus where ribosome subunits are assembled In prokaryotes, DNA processing takes place in the cytoplasm
  • Mitochondria and Chloroplasts: generate energy for the cell Mitochondria are self-replicating organelles that occur in various numbers, shapes, and sizes in the cytoplasm of all eukaryotic cells Respiration occurs in the cell mitochondria, which generate the cell's energy by oxidative phosphorylation, using oxygen to release energy stored in cellular nutrients typically pertaining to glucose to generate ATP Mitochondria multiply by binary fission, like prokaryotes Chloroplasts can only be found in plants and algae, and they capture the sun's energy to make carbohydrates through photosynthesis
Diagram of an endomembrane system
  • Endoplasmic reticulum: The endoplasmic reticulum ER is a transport network for molecules targeted for certain modifications and specific destinations, as compared to molecules that float freely in the cytoplasm The ER has two forms: the rough ER, which has ribosomes on its surface that secrete proteins into the ER, and the smooth ER, which lacks ribosomes The smooth ER plays a role in calcium sequestration and release
  • Golgi apparatus: The primary function of the Golgi apparatus is to process and package the macromolecules such as proteins and lipids that are synthesized by the cell
  • Lysosomes and Peroxisomes: Lysosomes contain digestive enzymes acid hydrolases They digest excess or worn-out organelles, food particles, and engulfed viruses or bacteria Peroxisomes have enzymes that rid the cell of toxic peroxides The cell could not house these destructive enzymes if they were not contained in a membrane-bound system
  • Centrosome: the cytoskeleton organiser: The centrosome produces the microtubules of a cell – a key component of the cytoskeleton It directs the transport through the ER and the Golgi apparatus Centrosomes are composed of two centrioles, which separate during cell division and help in the formation of the mitotic spindle A single centrosome is present in the animal cells They are also found in some fungi and algae cells
  • Vacuoles: Vacuoles sequester waste products and in plant cells store water They are often described as liquid filled space and are surrounded by a membrane Some cells, most notably Amoeba, have contractile vacuoles, which can pump water out of the cell if there is too much water The vacuoles of plant cells and fungal cells are usually larger than those of animal cells

Eukaryotic and prokaryotic

  • Ribosomes: The ribosome is a large complex of RNA and protein molecules They each consist of two subunits, and act as an assembly line where RNA from the nucleus is used to synthesise proteins from amino acids Ribosomes can be found either floating freely or bound to a membrane the rough endoplasmatic reticulum in eukaryotes, or the cell membrane in prokaryotes

Structures outside the cell membrane

Life timeline view • discuss • edit -4500 — – -4000 — – -3500 — – -3000 — – -2500 — – -2000 — – -1500 — – -1000 — – -500 — – 0 — water Single-celled
photosynthesis Eukaryotes Multicellular
Land life Dinosaurs     Mammals Flowers   ← Earliest Earth -4540 ← Earliest water ← Earliest life
-4100 ← LHB meteorites ← Earliest oxygen ← Atmospheric oxygenOxygen Crisis ← Earliest sexual reproduction ← Cambrian explosion ← Earliest humans P


n H
n Axis scale: millions of years
Also see: Human timeline & Nature timeline

Many cells also have structures which exist wholly or partially outside the cell membrane These structures are notable because they are not protected from the external environment by the semipermeable cell membrane In order to assemble these structures, their components must be carried across the cell membrane by export processes

Cell wall

Many types of prokaryotic and eukaryotic cells have a cell wall The cell wall acts to protect the cell mechanically and chemically from its environment, and is an additional layer of protection to the cell membrane Different types of cell have cell walls made up of different materials; plant cell walls are primarily made up of cellulose, fungi cell walls are made up of chitin and bacteria cell walls are made up of peptidoglycan



A gelatinous capsule is present in some bacteria outside the cell membrane and cell wall The capsule may be polysaccharide as in pneumococci, meningococci or polypeptide as Bacillus anthracis or hyaluronic acid as in streptococci Capsules are not marked by normal staining protocols and can be detected by India ink or methyl blue; which allows for higher contrast between the cells for observation:87


Flagella are organelles for cellular mobility The bacterial flagellum stretches from cytoplasm through the cell membranes and extrudes through the cell wall They are long and thick thread-like appendages, protein in nature A different type of flagellum is found in archaea and a different type is found in eukaryotes


A fimbria also known as a pilus is a short, thin, hair-like filament found on the surface of bacteria Fimbriae, or pili are formed of a protein called pilin antigenic and are responsible for attachment of bacteria to specific receptors of human cell cell adhesion There are special types of specific pili involved in bacterial conjugation

Cellular processes

Growth and metabolism

Main articles: Cell growth and Metabolism

Between successive cell divisions, cells grow through the functioning of cellular metabolism Cell metabolism is the process by which individual cells process nutrient molecules Metabolism has two distinct divisions: catabolism, in which the cell breaks down complex molecules to produce energy and reducing power, and anabolism, in which the cell uses energy and reducing power to construct complex molecules and perform other biological functions Complex sugars consumed by the organism can be broken down into simpler sugar molecules called monosaccharides such as glucose Once inside the cell, glucose is broken down to make adenosine triphosphate ATP, a molecule that possesses readily available energy, through two different pathways


Bacteria divide by binary fission, while eukaryotes divide by mitosis or meiosis Main article: Cell division

Cell division involves a single cell called a mother cell dividing into two daughter cells This leads to growth in multicellular organisms the growth of tissue and to procreation vegetative reproduction in unicellular organisms Prokaryotic cells divide by binary fission, while eukaryotic cells usually undergo a process of nuclear division, called mitosis, followed by division of the cell, called cytokinesis A diploid cell may also undergo meiosis to produce haploid cells, usually four Haploid cells serve as gametes in multicellular organisms, fusing to form new diploid cells

DNA replication, or the process of duplicating a cell's genome, always happens when a cell divides through mitosis or binary fission This occurs during the S phase of the cell cycle

In meiosis, the DNA is replicated only once, while the cell divides twice DNA replication only occurs before meiosis I DNA replication does not occur when the cells divide the second time, in meiosis II Replication, like all cellular activities, requires specialized proteins for carrying out the job

Protein synthesis

An overview of protein synthesis
Within the nucleus of the cell light blue, genes DNA, dark blue are transcribed into RNA This RNA is then subject to post-transcriptional modification and control, resulting in a mature mRNA red that is then transported out of the nucleus and into the cytoplasm peach, where it undergoes translation into a protein mRNA is translated by ribosomes purple that match the three-base codons of the mRNA to the three-base anti-codons of the appropriate tRNA Newly synthesized proteins black are often further modified, such as by binding to an effector molecule orange, to become fully active Main article: Protein biosynthesis

Cells are capable of synthesizing new proteins, which are essential for the modulation and maintenance of cellular activities This process involves the formation of new protein molecules from amino acid building blocks based on information encoded in DNA/RNA Protein synthesis generally consists of two major steps: transcription and translation

Transcription is the process where genetic information in DNA is used to produce a complementary RNA strand This RNA strand is then processed to give messenger RNA mRNA, which is free to migrate through the cell mRNA molecules bind to protein-RNA complexes called ribosomes located in the cytosol, where they are translated into polypeptide sequences The ribosome mediates the formation of a polypeptide sequence based on the mRNA sequence The mRNA sequence directly relates to the polypeptide sequence by binding to transfer RNA tRNA adapter molecules in binding pockets within the ribosome The new polypeptide then folds into a functional three-dimensional protein molecule

Movement or motility

Main article: Motility

Unicellular organisms can move in order to find food or escape predators Common mechanisms of motion include flagella and cilia

In multicellular organisms, cells can move during processes such as wound healing, the immune response and cancer metastasis For example, in wound healing in animals, white blood cells move to the wound site to kill the microorganisms that cause infection Cell motility involves many receptors, crosslinking, bundling, binding, adhesion, motor and other proteins The process is divided into three steps – protrusion of the leading edge of the cell, adhesion of the leading edge and de-adhesion at the cell body and rear, and cytoskeletal contraction to pull the cell forward Each step is driven by physical forces generated by unique segments of the cytoskeleton


Main article: Multicellular organism

Cell specialization

Staining of a Caenorhabditis elegans which highlights the nuclei of its cells

Multicellular organisms are organisms that consist of more than one cell, in contrast to single-celled organisms

In complex multicellular organisms, cells specialize into different cell types that are adapted to particular functions In mammals, major cell types include skin cells, muscle cells, neurons, blood cells, fibroblasts, stem cells, and others Cell types differ both in appearance and function, yet are genetically identical Cells are able to be of the same genotype but of different cell type due to the differential expression of the genes they contain

Most distinct cell types arise from a single totipotent cell, called a zygote, that differentiates into hundreds of different cell types during the course of development Differentiation of cells is driven by different environmental cues such as cell–cell interaction and intrinsic differences such as those caused by the uneven distribution of molecules during division

Origin of multicellularity

Multicellularity has evolved independently at least 25 times, including in some prokaryotes, like cyanobacteria, myxobacteria, actinomycetes, Magnetoglobus multicellularis or Methanosarcina However, complex multicellular organisms evolved only in six eukaryotic groups: animals, fungi, brown algae, red algae, green algae, and plants It evolved repeatedly for plants Chloroplastida, once or twice for animals, once for brown algae, and perhaps several times for fungi, slime molds, and red algae Multicellularity may have evolved from colonies of interdependent organisms, from cellularization, or from organisms in symbiotic relationships

The first evidence of multicellularity is from cyanobacteria-like organisms that lived between 3 and 35 billion years ago Other early fossils of multicellular organisms include the contested Grypania spiralis and the fossils of the black shales of the Palaeoproterozoic Francevillian Group Fossil B Formation in Gabon

The evolution of multicellularity from unicellular ancestors has been replicated in the laboratory, in evolution experiments using predation as the selective pressure


Main article: Evolutionary history of life

The origin of cells has to do with the origin of life, which began the history of life on Earth

Origin of the first cell

Stromatolites are left behind by cyanobacteria, also called blue-green algae They are the oldest known fossils of life on Earth This one-billion-year-old fossil is from Glacier National Park in the United States Further information: Abiogenesis and Evolution of cells

There are several theories about the origin of small molecules that led to life on the early Earth They may have been carried to Earth on meteorites see Murchison meteorite, created at deep-sea vents, or synthesized by lightning in a reducing atmosphere see Miller–Urey experiment There is little experimental data defining what the first self-replicating forms were RNA is thought to be the earliest self-replicating molecule, as it is capable of both storing genetic information and catalyzing chemical reactions see RNA world hypothesis, but some other entity with the potential to self-replicate could have preceded RNA, such as clay or peptide nucleic acid

Cells emerged at least 35 billion years ago The current belief is that these cells were heterotrophs The early cell membranes were probably more simple and permeable than modern ones, with only a single fatty acid chain per lipid Lipids are known to spontaneously form bilayered vesicles in water, and could have preceded RNA, but the first cell membranes could also have been produced by catalytic RNA, or even have required structural proteins before they could form

Origin of eukaryotic cells

Further information: Evolution of sexual reproduction

The eukaryotic cell seems to have evolved from a symbiotic community of prokaryotic cells DNA-bearing organelles like the mitochondria and the chloroplasts are descended from ancient symbiotic oxygen-breathing proteobacteria and cyanobacteria, respectively, which were endosymbiosed by an ancestral archaean prokaryote

There is still considerable debate about whether organelles like the hydrogenosome predated the origin of mitochondria, or vice versa: see the hydrogen hypothesis for the origin of eukaryotic cells

History of research

Main article: Cell theory
  • 1632–1723: Antonie van Leeuwenhoek teaches himself to make lenses, constructs basic optical microscopes and draws protozoa, such as Vorticella from rain water, and bacteria from his own mouth
  • 1665: Robert Hooke discovers cells in cork, then in living plant tissue using an early compound microscope He coins the term cell from Latin cella, meaning "small room" in his book Micrographia 1665
  • 1839: Theodor Schwann and Matthias Jakob Schleiden elucidate the principle that plants and animals are made of cells, concluding that cells are a common unit of structure and development, and thus founding the cell theory
  • 1855: Rudolf Virchow states that new cells come from pre-existing cells by cell division omnis cellula ex cellula
  • 1859: The belief that life forms can occur spontaneously generatio spontanea is contradicted by Louis Pasteur 1822–1895 although Francesco Redi had performed an experiment in 1668 that suggested the same conclusion
  • 1931: Ernst Ruska builds the first transmission electron microscope TEM at the University of Berlin By 1935, he has built an EM with twice the resolution of a light microscope, revealing previously unresolvable organelles
  • 1953: Watson and Crick made their first announcement on the double helix structure of DNA on February 28
  • 1981: Lynn Margulis published Symbiosis in Cell Evolution detailing the endosymbiotic theory

See also

  • Cell cortex
  • Cell culture
  • Cellular component
  • Cellular model
  • Cytorrhysis
  • Cytotoxicity
  • Lipid raft
  • Plasmolysis
  • Stem cell
  • Syncytium
  • Topic outline of cell biology
  • Vault organelle


  1. ^ a b "Cell" Online Etymology Dictionary Retrieved 31 December 2012 
  2. ^ Cell Movements and the Shaping of the Vertebrate Body in Chapter 21 of Molecular Biology of the Cell fourth edition, edited by Bruce Alberts 2002 published by Garland Science
    The Alberts text discusses how the "cellular building blocks" move to shape developing embryos It is also common to describe small molecules such as amino acids as "molecular building blocks"
  3. ^ Alberts, p 2
  4. ^ Campbell, Neil A; Brad Williamson; Robin J Heyden 2006 Biology: Exploring Life Boston, Massachusetts: Pearson Prentice Hall ISBN 0-13-250882-6 
  5. ^ Karp, Gerald 19 October 2009 Cell and Molecular Biology: Concepts and Experiments John Wiley & Sons p 2 ISBN 9780470483374 Hooke called the pores cells because they re- minded him of the cells inhabited by monks living in a monastery 
  6. ^ Alan Chong Tero 1990 Achiever's Biology Allied Publishers p 36 ISBN 9788184243697 In 1665, an Englishman, Robert Hooke observed a thin slice of" cork under a simple microscope A simple microscope is a microscope with only one biconvex lens, rather like a magnifying glass He saw many small box like structures These reminded him of small rooms called "cells" in which Christian monks lived and meditated 
  7. ^ Maton, Anthea 1997 Cells Building Blocks of Life New Jersey: Prentice Hall ISBN 0-13-423476-6 
  8. ^ a b Schopf, JW, Kudryavtsev, AB, Czaja, AD, and Tripathi, AB 2007 Evidence of Archean life: Stromatolites and microfossils Precambrian Research 158:141-155
  9. ^ a b Schopf, JW 2006 Fossil evidence of Archaean life Philos Trans R Soc Lond B Biol Sci 29;3611470:869-85
  10. ^ a b Peter Hamilton Raven; George Brooks Johnson 2002 Biology McGraw-Hill Education p 68 ISBN 978-0-07-112261-0 Retrieved 7 July 2013 
  11. ^ a b Campbell Biology—Concepts and Connections Pearson Education 2009 p 320 
  12. ^ Microbiology : Principles and Explorations By Jacquelyn G Black
  13. ^ European Bioinformatics Institute, Karyn's Genomes: Borrelia burgdorferi, part of 2can on the EBI-EMBL database Retrieved 5 August 2012
  14. ^ Satir, Peter; Christensen, ST; Søren T Christensen 2008-03-26 "Structure and function of mammalian cilia" Histochemistry and Cell Biology Springer Berlin/Heidelberg 129 6: 687–693 doi:101007/s00418-008-0416-9 PMC 2386530 PMID 18365235 1432-119X Retrieved 2009-09-12 
  15. ^ PH Raven , Evert RF, Eichhorm SE 1999 Biology of Plants, 6th edition WH Freeman, New York
  16. ^ Michie K, Löwe J 2006 "Dynamic filaments of the bacterial cytoskeleton" Annu Rev Biochem 75: 467–92 doi:101146/annurevbiochem75103004142452 PMID 16756499 
  17. ^ Ménétret JF, Schaletzky J, Clemons WM, et al December 2007 "Ribosome binding of a single copy of the SecY complex: implications for protein translocation" Mol Cell 28 6: 1083–92 doi:101016/jmolcel200710034 PMID 18158904 
  18. ^ Prokaryotes Newnes Apr 11, 1996 ISBN 9780080984735 
  19. ^ Campbell Biology—Concepts and Connections Pearson Education 2009 p 138 
  20. ^ Revathi Ananthakrishnan; Allen Ehrlicher "The Forces Behind Cell Movement" Biolsciorg Retrieved 2009-04-17 
  21. ^ Alberts B, Johnson A, Lewis J et al Molecular Biology of the Cell, 4e Garland Science 2002
  22. ^ Ananthakrishnan, R; Ehrlicher, A 2007 "The Forces Behind Cell Movement" Int J Biol Sci 3 5: 303–317 doi:107150/ijbs3303 PMC 1893118 PMID 17589565 
  23. ^ Becker, Wayne M; et al 2009 The world of the cell Pearson Benjamin Cummings p 480 ISBN 978-0-321-55418-5 
  24. ^ a b c Grosberg RK, Strathmann RR The evolution of multicellularity: A minor major transition Annu Rev Ecol Evol Syst 2007;38:621–654
  25. ^ http://publicwsuedu/~lange-m/Documnets/Teaching2011/Popper2011pdf
  26. ^ Bonner, John Tyler 1998 "The Origins of Multicellularity" PDF Integrative Biology: Issues, News, and Reviews 1 1: 27–36 doi:101002/SICI1520-660219981:1<27::AID-INBI4>30CO;2-6 ISSN 1093-4391 Archived from the original PDF, 02 MB on March 8, 2012 
  27. ^ El Albani A, Bengtson S, Canfield DE, Bekker A, Macchiarelli R, Mazurier A, Hammarlund EU, Boulvais P, Dupuy JJ, Fontaine C, Fürsich FT, Gauthier-Lafaye F, Janvier P, Javaux E, Ossa FO, Pierson-Wickmann AC, Riboulleau A, Sardini P, Vachard D, Whitehouse M, Meunier A 1 July 2010 "Large colonial organisms with coordinated growth in oxygenated environments 21 Gyr ago" Nature 466 7302: 100–104 Bibcode:2010Natur466100A doi:101038/nature09166 ISSN 0028-0836 PMID 20596019 
  28. ^ Orgel LE 1998 "The origin of life--a review of facts and speculations" Trends Biochem Sci 23 12: 491–5 doi:101016/S0968-00049801300-0 PMID 9868373 
  29. ^ Griffiths G December 2007 "Cell evolution and the problem of membrane topology" Nature reviews Molecular cell biology 8 12: 1018–24 doi:101038/nrm2287 PMID 17971839 
  30. ^ " I could exceedingly plainly perceive it to be all perforated and porous, much like a Honey-comb, but that the pores of it were not regular these pores, or cells, were indeed the first microscopical pores I ever saw, and perhaps, that were ever seen, for I had not met with any Writer or Person, that had made any mention of them before this " – Hooke describing his observations on a thin slice of cork Robert Hooke
  •  This article incorporates public domain material from the NCBI document "Science Primer"


  • Alberts, Bruce; Johnson, Alexander; Lewis, Julian; Morgan, David; Raff, Martin; Roberts, Keith; Walter, Peter 2015 Molecular Biology of the Cell 6th ed Garland Science p 2 ISBN 978-0815344322 

External links

  • MBInfo - Descriptions on Cellular Functions and Processes
  • MBInfo - Cellular Organization
  • Inside the Cell - a science education booklet by National Institutes of Health, in PDF and ePub
  • Cells Alive!
  • Cell Biology in "The Biology Project" of University of Arizona
  • Centre of the Cell online
  • The Image & Video Library of The American Society for Cell Biology, a collection of peer-reviewed still images, video clips and digital books that illustrate the structure, function and biology of the cell
  • HighMag Blog, still images of cells from recent research articles
  • New Microscope Produces Dazzling 3D Movies of Live Cells, March 4, 2011 - Howard Hughes Medical Institute
  • WormWeborg: Interactive Visualization of the C elegans Cell lineage - Visualize the entire cell lineage tree of the nematode C elegans
  • Cell Photomicrographs


  • Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P 2014 Molecular Biology of the Cell 6th ed Garland ISBN 9780815344322 ; The fourth edition is freely available from National Center for Biotechnology Information Bookshelf
  • Lodish H, Berk A, Matsudaira P, Kaiser CA, Krieger M, Scott MP, Zipurksy SL, Darnell J 2004 Molecular Cell Biology 5th ed WH Freeman: New York, NY ISBN 978-0-7167-4366-8 
  • Cooper GM 2000 The cell: a molecular approach 2nd ed Washington, DC: ASM Press ISBN 0-87893-102-3 

cell biology and genetics, cell biology animation, cell biology for kids, cell biology international, cell biology journal, cell biology notes, cell biology pdf, cell biology quiz, cell biology syllabus, cell biology textbook

Cell (biology) Information about

Cell (biology)

  • user icon

    Cell (biology) beatiful post thanks!


Cell (biology)
Cell (biology)
Cell (biology) viewing the topic.
Cell (biology) what, Cell (biology) who, Cell (biology) explanation

There are excerpts from wikipedia on this article and video

Random Posts



A book is a set of written, printed, illustrated, or blank sheets, made of ink, paper, parchment, or...
Boston Renegades

Boston Renegades

Boston Renegades was an American women’s soccer team, founded in 2003 The team was a member of the U...
Sa Caleta Phoenician Settlement

Sa Caleta Phoenician Settlement

Sa Caleta Phoenician Settlement can be found on a rocky headland about 10 kilometers west of Ibiza T...

Bodybuildingcom is an American online retailer based in Boise, Idaho, specializing in dietary supple...