Signaling in Yeast

Yeasts are single-celled eukaryotes; therefore, they have a nucleus and organelles characteristic of more complex life forms. Comparisons of the genomes of yeasts, nematode worms, fruit flies, and humans illustrate the evolution of increasingly-complex signaling systems that allow for the efficient inner workings that keep humans and other complex life forms functioning correctly.

The components and processes found in yeast signals are similar to those of cell-surface receptor signals in multicellular organisms. Budding yeasts are able to participate in a process that is similar to sexual reproduction that entails two haploid cells combining to form a diploid cell . In order to find another haploid yeast cell that is prepared to mate, budding yeasts secrete a signaling molecule called mating factor. When mating factor binds to cell-surface receptors in other yeast cells that are nearby, they stop their normal growth cycles and initiate a cell signaling cascade that includes protein kinases and GTP-binding proteins that are similar to G-proteins.

Identify the difference between the graph of a linear equation and linear inequality

Recall that solutions to linear inequalities are whole sets of numbers, rather than just one number, like you find with solutions to equalities (equations).

Here is an example from the section on solving linear inequalities:

Solve for p. [latex]4p+5<29[/latex]

[latex] \displaystyle \begin{array}{l}4p+5<\,\,\,29\\\underline{\,\,\,\,\,\,\,\,\,-5\,\,\,\,\,\,\,-5}\\\underline{4p}\,\,\,\,\,\,\,\,<\,\,\underline{24}\,\,\\4\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,4\\\,\,\,\,\,\,\,\,\,\,\,p<6\end{array}[/latex]

You can interpret the solution as p can be any number less than six. Now recall that we can graph equations of lines by defining the outputs, y, and the inputs, x, and writing an equation.