In addition, each of these proteins acts to block the other specifically, Dpp is a negative transcription factor for Wg, while Wg interferes with the translation of Dpp. Interestingly, Wg (wingless) protein acts in the anterior wing cells just as Dpp acts in the posterior ones. Dpp is thus essential for growth of the wing cells and patterning beyond the central domain.
CONCENTRATION GRADIENT DEFINITION BIOLOGY CODE
The Dpp transcription factor induces the production of a host of target genes, including genes that code for other transcription factors, and it also activates pathways that result in expansion of the wing pattern. The product of engrailed, along with a partner substance, forms a transcription factor that induces a regulatory protein known as hedgehog (Hh), which, in turn, induces expression of Dpp in the P compartment along the D/V axis and diffuses a short distance into the A compartment, where it controls the pattern of the central domain of the wing. P compartment cells are identified by the expression of the selector gene called engrailed ( en). This disc is subdivided into compartments, with an anterior/posterior (A/P) axis and dorsal/ventral (D/V) axis. In fruit flies, the wing forms from a structure called the larval imaginal disc, which is a sac of epithelial cells that are reserved for future wing development. In fact, this substance is essential for the growth of wing cells. For instance, one good example of a transcription factor regulated by morphogen gradients is decapentaplegic (Dpp), which is expressed in developing wings of fruit flies (Tabata, 2001). This information has yielded several powerful insights. To learn more about the role of morphogens in bilaterian development, scientists have collected data on the genetics of these proteins in insects, particularly the fruit fly Drosophila melanogaster. Gradient systems are believed to be an economical way for cells to define body patterning, as they make use of a small number of signal molecules to make various cell types, without requiring novel signaling systems for each type.
![concentration gradient definition biology concentration gradient definition biology](https://files.askiitians.com/cdn1/cms-content/biologytransport-in-plantsosmosis-and-diffusion_1.jpg)
For example, the expression of such gradients controls how long your fingers should be, where your nose is on your face, and other specifics about body structure.
CONCENTRATION GRADIENT DEFINITION BIOLOGY SERIES
Based on the concentration of the regulatory protein in each particular cell, a series of subsequent signals (cascades) and responses to them dictate the direction and extent of cell growth and development (Figure 2). As a result, concentration gradients of important regulatory proteins form across the developmental field of an embryo, which defines a positioning value for each cell. Different concentrations of the morphogen result in the induction or inhibition of gene expression of other genes (Figure 1). These molecules are extracellular and are believed to influence tissue morphogenesis by diffusing along the surfaces of cells from a concentrated source. The specific signaling molecules that are involved in this process are called morphogens. Relatively speaking, only a small number of genes are involved in determining body patterns during development (Tabata, 2001). Indeed, even with the complex mechanisms of gene expression that determine cell differentiation patterns, bilateralism would not occur unless there were additional signals being transmitted during embryogenesis to establish this body pattern.
![concentration gradient definition biology concentration gradient definition biology](https://image.slidesharecdn.com/bdiffusionandosmosis-090420075154-phpapp02/95/b-diffusion-and-osmosis-9-728.jpg)
![concentration gradient definition biology concentration gradient definition biology](https://geteducationcrunch.com/wp-content/uploads/2020/11/Concentration-Gradient.png)
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Somehow, during early embryonic development, cellular signals dictate that all bilaterian organisms (i.e., those with mirror-image halves) should be built with two similar sides, a top and a bottom, and a front and a back (Peel et al., 2005).