CELL SIGNALING

“Real Life” Cell Communication: Flight or Fight Response While watching the movie clip,

record at least TWO responses cells have to signals.

Pathways with Friends

Handout

Diagram

Steps of Cell Signaling

1. Reception

2. Signal Transduction

3. Cellular Response

Reception

1. G-Protein

2. Tyrosine Kinase

3. Ligand-Gated Ion Channel

4. Intracellular Receptor

Online Simulation:http://media.pearsoncmg.com/bc/bc_campbell_biology_7/media/interactivemedia/activities/load.html?11&B

1. Molecule the receptor binds to?

2. Action of the receptor?

Signal Transduction

Second Messengers

a. Cyclic AMP

b. Calcium ions

c. Protein kinases

Online Simulation:http://media.pearsoncmg.com/bc/bc_campbell_biology_7/media/interactivemedia/activities/load.html?11&C

1. Receptor/s the messenger works with

2. Action of the messenger

Cellular ResponsesExamples

a. Testosterone (intracellular receptors)

b. Cell Reproduction/Cancer (kinase messengers)

c. Cholera, Viagra (cAMP secondary messengers)

d. Muscle Contraction (Ca2+ secondary messengers)

Online Simulation:

http://media.pearsoncmg.com/bc/bc_c

ampbell_biology_7/media/interactive

media/activities/load.html?11&D

Cell Cycle

Cell Cycle Animations

1) Stages of the Cell Cycle

2) Mitosis Movie

Regulation of Mitosis

Cyclins - Their levels in the cell rise and fall with the stages of the cell cycle.

Cyclin-dependent kinases (Cdks) G1 (Cdk4)  S-phase (Cdk2)  M-phase (Cdk1)

- Levels in the cell remain fairly stable, but each must bind the appropriate cyclin (whose levels fluctuate) in order to be activated.

Anaphase-promoting complex (APC) or cyclosome (APC/C)

allows the sister chromatids to separate degrades the mitotic cyclins

Role of Cyclin & Cdks

Protein kinase + Cyclin = Cdks (Cyclin Dependent Kinases)

Advance the cell at G1 and G2 stages MPF is a type of Cdk + Cyclin

1. MPF signals mitosis to begin

2. Cyclin begins

to degrad

e

3. Mitosis ends

4. Cdk portion recycled

5. Cyclins build up

and trigger mitosis again

Cancer

HHMI Video Clip

http://www.hhmi.org/biointeractive/cancer/lectures.html

p53 gene affects production of Cdk2 and apoptosis