Cell biology: Wikis

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From Wikipedia, the free encyclopedia

Cell biology (formerly cytology, from the Greek kytos, "container") is an academic discipline that studies cells – 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 encompasses both the great diversity of single-celled organisms like bacteria and protozoa, as well as the many specialized cells in multicellular organisms like humans.

Knowing the components of cells and how cells work is fundamental to all biological sciences. Appreciating the similarities and differences between cell types is particularly important to the fields of cell and molecular biology as well as to biomedical fields such as cancer research and developmental biology. These fundamental similarities and differences provide a unifying theme, sometimes allowing the principles learned from studying one cell type to be extrapolated and generalized to other cell types. Hence, research in cell biology is closely related to genetics, biochemistry, molecular biology, Immunology, and developmental biology.

Understanding cells in terms of their molecular components.

Contents

Processes

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Movement of proteins

Endothelial cells under the microscope. Nuclei are stained blue with DAPI, microtubles are marked green by an antibody and actin filaments are labelled red with phalloidin.

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 (known as membrane proteins), are transported into the "rough" endoplasmic reticulum (ER) during synthesis. This process can be followed by transportation and processing 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

Internal cellular structures

Electron micrograph.

Techniques used to study cells

Drosophila m oogenesis.png

Cells may be observed under the microscope. This includes the Optical Microscope, Transmission Electron Microscope, Scanning Electron Microscope, Fluorescence Microscope, and by Confocal Microscopy.

Several different techniques exist to study cells.

  • Cell culture is the basic technique of growing cells in a laboratory independent of an organism.
  • Immunostaining, also known as immunohistochemistry, is a specialized histological method used to localize proteins in cells or tissue slices. Unlike regular histology, which uses stains to identify cells, cellular components or protein classes, immunostaining requires the reaction of an antibody directed against the protein of interest within the tissue or cell. Through the use of proper controls and published protocols (need to add reference links here), specificity of the antibody-antigen reaction can be achieved. Once this complex is formed, it is identified via either a "tag" attached directly to the antibody, or added in an additional technical step. Commonly used "tags" include fluorophores or enzymes. In the case of the former, detection of the location of the "immuno-stained" protein occurs via fluorescence microscopy. With an enzymatic tag, such as horse radish peroxidase, a chemical reaction is carried out that results in a dark color in the location of the protein of interest. This darkened pattern is then detected using light microscopy.
  • Computational genomics is used to find patterns in genomic information [1]
  • DNA microarrays identify changes in transcript levels between different experimental conditions.
  • Gene knockdown mutates a selected gene.
  • In situ hybridization shows which cells are expressing a particular RNA transcript.
  • PCR can be used to determine how many copies of a gene are present in a cell.
  • Transfection introduces a new gene into a cell, usually an expression construct

Purification of cells and their parts Purification may be performed using the following methods:

See also

Notable cell biologists

References

  1. ^ Cristianini, N. and Hahn, M. Introduction to Computational Genomics, Cambridge University Press, 2006. (ISBN 9780521671910 | ISBN 0521671914)

External links


Study guide

Up to date as of January 14, 2010
(Redirected to Cell Biology article)

From Wikiversity

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Contents

Introduction

Welcome!

This is the main page for the Cell Biology course, in the Department of Cell Biology. Cell biology is typically one of the specialized courses taken by students after they have had a more general introduction to modern biology. A basic introduction to biology, as can be gained from Michael McDarby's Online Introduction to Biology or the General Biology textbook at Wikibooks, is a possible prerequisite. Chemistry is the backbone of Cellular Biology so some knowledge of Biochemistry is necessary for the concepts. Check out these sites for more information chemistry or biochemistry. However, Cell Biology is fundamental to all of biology, and can serve as a reasonable starting point for students exploring the field.

It seems that many people checking out this page are looking to supplement their coursework. Which was what I was looking for too when I found this site. I have added lectures that are the equivalent to the college course normally offered a junior or senior level. It correlates with the free video lectures available on ITunes U. I would love for someone to post additional resources, notes or comments. This can be a resource that will help other students share information for years to come. As you can tell from below, there are lectures with a more general aim and then the lectures that delve more deeply into the subject and require a greater knowledge of biochemistry.

For YOU!

Illustration of "cell sorting-out".

Why is this course different from all other courses?

  1. All other courses have clearly distinct students and instructors; in this one, the students help serve as instructors (and vice versa).
  2. All other courses meet at a set time, and have set deadlines; this one is designed for anyone, anytime, anywhere and can be completed (or not) at any rate.
  3. This course is equivalent to a college course and you can learn the material at home for free!

What should you do?

  • Read through the existing lessons. Feel free to edit and improve them.
  • You can pick a topic in Cell Biology that fascinates you and start reading. As you discover interesting information, add what you have learned to a wiki page about the topic you are learning. Keep a record of what you read and what you write.
  • The present instructors have found that the best way to learn is create lessons of your own.
  • If you have another idea of what to do or would like to design a plan of study, feel free to discuss it with an instructor (such as JWSchmidt) or sign up as one! This course is a collaborative effort between students and instructors.
  • A format has been set up and links to video lectures have been put in. Please help by adding your own notes and supplemental resources you have found.
  • Construction of new course materials would be a big help in Wikiversity's Cell Biology Improvement Drive! You're welcome to join the Improvement Drive in additional ways, including creating or revising other cell biology pages. For example, the Wikibooks Cell Biology textbook needs more work.

Existing Lessons

Lesson 1: Introduction to Cell Biology

Lesson 2: Membrane Structure: Lipids

Lesson 3: Membrane Structure: Proteins

Lesson 4: Membrane Structure: Dynamics

Lesson 5: Membrane Transport: Permeases and Channels

Lesson 6: Membrane Transport: Nucleocytoplasmic Exchange

Lesson 7: Membrane Assembly: Signal Hypothesis

Lesson 8: Membrane Assembly: Mechanism

Lesson 9: Membrane Assembly: Topography

Lesson 10: Cholesterol Regulation

Lesson 11: Membrane Vesicular Transport

Lesson 12: Lysosomal Protein Transport

Lesson 13: Action Potential

Lesson 14: Synaptic Transmission

Lesson 15: Membrane Fusion

Lesson 16: Visualizing Cells: Principles of Microscopy

Lesson 17: Actin Filaments: Structural and Dynamic Properties

Lesson 18: Actin-binding Proteins and Cell Migration

Lesson 19: Actin and Myosin in Skeletal Muscle Contraction

Lesson 20: Regulation of Contraction in Muscle and Nonmuscle Cells

Lesson 21: Cell Adhesion, Motility and Division

Lesson 22: Intermediate Filaments and Septins

Lesson 23: Microtubules: Structure and Dynamic Properties

Lesson 24: Regulation of Microtubule Organization and Motility

Lesson 25: Nuclear and Chromatin Structure

Lesson 26: Mitosis and Cell Division

Lesson 27: Mitotic Spindle Assembly and Function

Lesson 28: Meiosis

Lesson 29: Cell Communication: Ligand and Receptors

Lesson 30: Receptors

Lesson 31: G-Protein Coupled Receptor Signaling I

Lesson 32: G-Protein Coupled Receptor Signaling II

Lesson 33: Receptor Tyrosine Kinase Signaling

Lesson 34: The Ras-MAP Kinase Pathway

Lesson 35: Regulation of Cell Growth

Lesson 36: The Cell Cycle I

Lesson 37: The Cell Cycle II

Lesson 38: The Cell Cycle III

Lesson 39: Checkpoints

Lesson 40: Apoptosis

Lesson 41: Cancer

Lesson 42: Cancer Review

Writing Your Own Lesson

Wikiversity offers instructions for how to write a page using the wiki language, and how to create useful content specifically for Wikiversity.

Resources

On Wikiversity

Elsewhere on the Web

Wikipedia articles

Wikipedia categories

Participants

If you are a student in this course, please sign in so that we can try to develop a community. Hopefully, there can be group projects.

  • Lazyquasar 05:36, 29 November 2005 (UTC) Weak preparation. Interested in fundamentals. May shift abrubtly to lower level course or drop as personal activities progress.
    • Personally, I think one of the most interesting things about cells is how they make it possible for us to learn. I'd suggest that you try to identify some aspect of biology that is of particulat interest to you, all the "fundamentals" can be learned about in the context of what you find most interesting about life/behavior/biology. --JWSurf 22:51, 30 November 2005 (UTC)
  • JedOs 02:26, 9 December 2005 (UTC) I am Biology major student at college working on my Bachealors in Biology. I am hard worker yet I have areas of frustration. I'm not sure how this free course thing works, so please tell me at my talk page, http://en.wikipedia.org/wiki/User:JedOs
  • Lukner 16:15, 19 February 2006 (UTC). I am a second-career pre-med student at the University of Texas at Austin. I have a Ph.D. in Chemical Engineering, and I'm taking a few classes to satisfy my pre-med requirements. I am taking a Cell Biology course at UT, and this online course might provide some additional material to supplement the course I'm already taking.
    • What biology/medicine topics are you interested in? --JWSurf 04:13, 17 March 2006 (UTC)
  • Srinivas 06:13, 7 April 2006 (UTC) I am interested in learning molecular cell biology. I have post graduate degree in computer science and mathematics. I am using my long term cancer treatment (vacation!) time in learning new subjects. Thank you for maintaining this free course. I have high school knowledge of biology. Hopefully as I progress, I will find out which fundamental concepts I need to refresh in order to catch up with the course.
  • PJC 12:54, 10 May 2006 (UTC) I'm a third year Biochemistry student at the University of Nottingham (UK). I'm interested in how cells participate to form the brain (as mentioned above), particularly the role of the ubiquitin-proteasome system (UBS). I'm also interested in the regulation of transcription by the SRE-SRF-TCF complex; and the cellular basis of cancer.

(note: all of the above were added when this page existed at Wikibooks)

  • Davichito 00:26, 27 September 2008 (UTC). I am a self-taught computer programmer who is very interested in biology and has read some chapters of Curtis' biology book. I hope to understand biology because I think life is the great mystery in the universe; also the most complex one.
  • User:JWSchmidt - See: Cell Biology/JWSchmidt for my thoughts about cell biology and learning.
  • Steven Fruitsmaak
  • Soft.tofu 14:26, 5 October 2006 (UTC) I am a BSEE doing IT work for scientific product distributor. I hope to understand medicine a little more. Starting from scratch, I guess, with basic biology background. My wife is dying from metastatic gastric cancer, signet ring cell. If nothing else, this is a response to her oncologist saying "Read some medical books."
  • Joshoisasleep 00:00, 4 November 2006 (UTC) I have a personal interest and would like to learn more before going on to brick and mortar study...
  • AFriedman 07:10, 18 December 2008 (UTC) I perform research on Wikiversity (see my Userpage for details) and stumbled upon this page while trying to add materials to a course I'm developing in neuroscience. Neuroscience is a field that also needs content development, perhaps even more desperately.
  • ObubbledO 01:30pm, 25 February 2009

Wikibooks

Up to date as of January 23, 2010
(Redirected to Cell Biology article)

From Wikibooks, the open-content textbooks collection

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Contents

Keratin in epithelial cells

Resources

Meta


Simple English

Cell biology is the study of how living cells work. This includes the structure and function of the cell organelles, and the carbon-based molecules which cells produce. The most important molecules are DNA, RNA and proteins.[1]

The most important structures in the cell are the nucleus and the chromosomes, but there are many others. The structure of eukaryotic cells is much more complex than prokaryotic cells. This is because endosymbiosis has occurred: some or all of the eukaryote organelles are former prokaryotes. Examples are mitochondria and plastids.[2][3]

The most important function of cells is to divide by mitosis or meiosis. Cells in a multicellular organism also specialise in different functions, and the different types may look quite to each other.

  • Cytology is mostly about the appearance and structure of cells.

References

  1. Gall JG & McIntosh JR eds 2001. Landmark papers in cell biology. Bethesda, MD and Cold Spring Harbor, NY: The American Society for Cell Biology and Cold Spring Harbor Laboratory Press.
  2. Alberts B, Johnson A. Lewis J. Raff M. Roberts K. Walter P. 2008. Molecular biology of the cell, 5th ed. Garland.
  3. Lodish H. Berk A. Matsudaira P. Kaiser CA. Krieger M. Scott MP. Zipurksy SL. Darnell J. 2004. Molecular cell biology, 5th ed. WH Freeman: NY.



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