bio361week11

Week 11

Major concept goals

-Positive feedback leads to rapid activation of MPF

-MPF promotes M-phase through its kinase activity

-How MPF directly controls nuclear envelope breakdown and APC activation

-The stages of M-phase: prophase, metaphase, anaphase, telophase

-How initiation of anaphase is controlled through APC activation, inhibition of securin, and activation of separase that degrades cohesin

-How DNA is segregated during anaphase

-Degradation of cyclin and inhibition of MPF activity leads to telophase and re-entry into interphase

-The logic of cell-cell signaling

-Receptors always transform the signal into a new response

-What happens to cause glucose release into the bloodstream during the fight or flight response

-How a signal can be amplified within a cell

Overview of content

I. What happens when MPF is activated--after it activates more MPF!

    A. Nuclear envelope breakdown so that microtubules in the cytoplasm can interact with DNA at kinetochores

    B. APC activation by MPF activity and inhibition of the spindle assembly checkpoint in metphase

    C. The activation of APC leads to sister chromatid separation and anaphase

    D. During anaphase kinetochore microtubules shorten leading to the separation and segregation  of chromosomes

    E. Telophase is a reversal of prophse due to the degradation of cyclin and loss of MPF activity

II. How do cells communicate 

    A. Yeast mating as an example of cell to cell communication

    B. What are signals?

    C. What are receptors and where are they localized?

III. An example of 7TM (GPCR) signaling

    A. The fight or flight response is caused by the adrenaline signal

    B. How 7-TM receptors are activated

    C. Activated 7-TM receptors act as a GEF for heterotrimeric G-proteins

    D. G protein activation and downstream steps in the signaling cascade to breakdown glycogen to produce glucose

    E. How this pathway amplifies the signal