Download Analyzing Cell Communication 2016

Analyzing Cell Communication
Diagram #1
1. Epinephrine is a protein hormone, used in the fight or flight response, that stimulates the breakdown of the storage
of glycogen into glucose within liver cells. The glucose will then be released into the bloodstream or used by the cell.
What is the role that epinephrine plays in this pathway?
2. Phosphorylase is the enzyme that hydrolyzes glycogen into glucose. How does the enzyme become functional?
3. If you mixed epinephrine with phosphorylase and glycogen in a test tube, would glucose be generated? Why or why
not?
Diagram #2
1. Why is a cell-surface receptor protein not required for this
hormone to enter the cell?
2. How does the estradiol hormone affect the cell?
3. How would the response be affected if the receptor protein
was mutated and could not bind to estradiol?
Diagram #3
1. What is a protein kinase and what is its role in a signal transduction pathway?
2. What would happen if a mutation in protein kinase 3 made it incapable to being phosphorylated?
3. Phosphatases are enzymes that dephosphorylate protein kinases. Some human diseases are associated with
malfunctioning phosphatases. How would such proteins affect signaling pathways?
Diagram #4
A death signal is received when a molecule called Fas binds its cell-surface receptor. The binding of many Fas molecules
to receptors causes the receptors to cluster together. The intracellular regaions of the receptors, when together, bind
to proteins called adaptor proteins. These in turn bind to inactive molecules of caspase-8, which become activated and
then activate caspase-3. Once activated, caspase-3 initiate apoptosis. Make a drawing of this apoptotic pathway that
operates in human immune cells.
Diagram #5
1. What is the difference between a protein kinase and a second messenger?
2. How many 2nd messengers are in the pathway of De-etiolation?
3. How would the response be affected if a tomato plant was injected with cGMP but not given sunlight?
Diagram #6
1. At what point in the pathway is it turned into a cascade?
2. Phosphodiesterase is the enzyme that inactivates cAMP by changing it to AMP. What would happen if a molecule
that inactivated phosphodiesterase was introduced into the cell?
3. When a signal transduction pathway involves a phosphorylation cascade, how does the cell’s response get turned
off?
Diagram #7
1.When phospholipase C is activated by the binding of a ligand to a receptor, how is the IP3-gated calcium channels
affected?
2. Besides the G protein receptor, how else can this pathway be initiated?
3. If the calmodulin protein was mutated, how would that affect the second messenger calcium?
Diagram 8
1. When a yeast cell binds mating factor molecules from a cell of the opposite mating type, a signaling pathway causes it
to grow a projection toward the potential mate. The cell with the projection is called a “shmoo”. How does the
projection get made?
2. What role does the Formin have in the pathway?
3. What prediction could be made if the yeast had a mutation that prevented the G protein from binding GTP?