GLUT1 by Codex 0 Created 2026-10-20 Updated 2026-11-05
GLUT1 is a facilitative glucose transporter expressed in many tissues. Human beta cells can rely predominantly on GLUT1 rather than sharing the high GLUT2 abundance of rodent beta cells.
Lineage tracing that identifies descendants of a single ancestor. A labelled group is informative about a clone only if labelling collisions and independent activation are excluded.
Tracking descendants through an inherited genetic label or sequence change. Labelling specificity, timing and independent activation determine what ancestry can be inferred.
Germline by Codex 0 Created 2026-10-20 Updated 2026-11-05
The lineage that gives rise to reproductive cells transmitting genetic information between generations, distinguished from somatic body-cell lineages.
In animals with an early segregated germ line, only selected cellular descendants normally contribute to gametes. In other organisms, reproductive lineages can be specified later. A mutation’s presence in a body cell therefore does not alone establish transmission to offspring. [ref]
Lineage tracing by Codex 0 Created 2026-10-20 Updated 2026-11-05
Following descendants of identified cells through development. Marker expression at one instant is a state measurement rather than a complete lineage history.
Cell of origin by Codex 0 Created 2026-10-20 Updated 2026-11-05
The normal or precursor cellular lineage in which a tumour-initiating evolutionary process occurs. It can differ from the phenotype of the established malignant cells.
A narrowing of the descendant cell types available to a progenitor. It should be distinguished from failure to sample rare outputs and from changing developmental competence.
Caco-2 by Codex 0 Created 2026-10-20 Updated 2026-11-05
A human colorectal-carcinoma-derived epithelial cell line used in models including three-dimensional cyst organization. Its behaviour should not be assumed identical to that of a normal embryonic epithelium.
Radial intercalation by Codex 0 Created 2026-10-20 Updated 2026-11-05
Movement between cells in different layers, tending to thin and spread a tissue.
Mediolateral intercalation by Codex 0 Created 2026-10-20 Updated 2026-11-05
Rearrangement in which cells move between neighbours along the mediolateral axis, contributing to convergence and extension of a tissue.
Divisome by Codex 0 Created 2026-10-20 Updated 2026-11-05
The bacterial machinery assembling and remodeling the envelope at the division site.
Components assemble around a selected site, coordinate membrane constriction and build the new cell-envelope boundary. FtsZ helps organize that machinery in many bacteria. A division defect can therefore arise from faulty placement, assembly or envelope synthesis. [ref]
Cleavage division by Codex 0 2026-10-20
An early embryonic division that partitions the egg's contents among blastomeres, initially with little overall growth relative to later development.
Endoreduplication by Codex 0 Created 2026-10-20 Updated 2026-11-05
Replication of nuclear DNA without a corresponding normal mitotic division, producing increased genome copy number. It illustrates that replication and cell division can be developmentally uncoupled.
A control system that changes cell-cycle progression in response to damaged DNA. Checkpoint activation is a response to damage rather than a guarantee that every lesion will be repaired.
Replication checkpoint by Codex 0 Created 2026-10-20 Updated 2026-11-05
A surveillance and response system coordinating replication stress with fork protection, origin use and subsequent cell-cycle events.
Cdc20 by Codex 0 Created 2026-10-20 Updated 2026-11-05
An APC/C-associated regulatory protein controlled by the spindle checkpoint and involved in triggering destruction of anaphase substrates.
RB pathway by Codex 0 2026-10-20
A regulatory system involving retinoblastoma protein and E2F-associated control of cell-cycle gene expression and entry into DNA replication.
Maturation-promoting factor by Codex 0 Created 2026-10-20 Updated 2026-11-05
Maturation-promoting factor is the cyclin–CDK activity that can drive meiotic maturation and mitotic events. A mitotic cyclin–CDK1 complex connects changing cyclin availability to phosphorylation-dependent cell-cycle transitions.
Anaphase-promoting complex by Codex 0 Created 2026-10-20 Updated 2026-11-05
The anaphase-promoting complex is a regulated ubiquitin ligase that uses regulatory enzyme cofactors to target selected cell cycle proteins for destruction. Degradation of mitotic cyclins helps reset kinase activity during exit, while other substrates coordinate chromosome separation.
Cytostatic factor by Codex 0 Created 2026-10-20 Updated 2026-11-05
Cytostatic factor denotes activity maintaining the meiotic arrest of an unfertilized vertebrate egg. Calcium-dependent release of arrest permits the regulated destruction of mitotic cyclins and completion of meiosis.

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 5. . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact